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/jvmtiThreadState.inline.hpp"
47 #include "prims/resolvedMethodTable.hpp"
48 #include "prims/methodComparator.hpp"
49 #include "runtime/deoptimization.hpp"
50 #include "runtime/relocator.hpp"
51 #include "utilities/bitMap.inline.hpp"
52 #include "utilities/events.hpp"
53
54 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
55 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
56 Method** VM_RedefineClasses::_matching_old_methods = NULL;
57 Method** VM_RedefineClasses::_matching_new_methods = NULL;
58 Method** VM_RedefineClasses::_deleted_methods = NULL;
59 Method** VM_RedefineClasses::_added_methods = NULL;
60 int VM_RedefineClasses::_matching_methods_length = 0;
61 int VM_RedefineClasses::_deleted_methods_length = 0;
62 int VM_RedefineClasses::_added_methods_length = 0;
63 Klass* VM_RedefineClasses::_the_class = NULL;
64
65
66 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
67 const jvmtiClassDefinition *class_defs,
68 JvmtiClassLoadKind class_load_kind) {
69 _class_count = class_count;
70 _class_defs = class_defs;
71 _class_load_kind = class_load_kind;
72 _any_class_has_resolved_methods = false;
73 _res = JVMTI_ERROR_NONE;
74 }
75
76 static inline InstanceKlass* get_ik(jclass def) {
77 oop mirror = JNIHandles::resolve_non_null(def);
78 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
79 }
80
81 // If any of the classes are being redefined, wait
82 // Parallel constant pool merging leads to indeterminate constant pools.
83 void VM_RedefineClasses::lock_classes() {
84 MutexLocker ml(RedefineClasses_lock);
85 bool has_redefined;
86 do {
87 has_redefined = false;
88 // Go through classes each time until none are being redefined.
89 for (int i = 0; i < _class_count; i++) {
90 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
91 RedefineClasses_lock->wait();
92 has_redefined = true;
93 break; // for loop
94 }
95 }
96 } while (has_redefined);
97 for (int i = 0; i < _class_count; i++) {
98 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
99 }
100 RedefineClasses_lock->notify_all();
101 }
102
103 void VM_RedefineClasses::unlock_classes() {
104 MutexLocker ml(RedefineClasses_lock);
105 for (int i = 0; i < _class_count; i++) {
106 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
107 "should be being redefined to get here");
108 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
109 }
110 RedefineClasses_lock->notify_all();
111 }
112
113 bool VM_RedefineClasses::doit_prologue() {
114 if (_class_count == 0) {
115 _res = JVMTI_ERROR_NONE;
116 return false;
117 }
118 if (_class_defs == NULL) {
119 _res = JVMTI_ERROR_NULL_POINTER;
120 return false;
121 }
122 for (int i = 0; i < _class_count; i++) {
123 if (_class_defs[i].klass == NULL) {
124 _res = JVMTI_ERROR_INVALID_CLASS;
125 return false;
126 }
127 if (_class_defs[i].class_byte_count == 0) {
128 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
129 return false;
130 }
131 if (_class_defs[i].class_bytes == NULL) {
132 _res = JVMTI_ERROR_NULL_POINTER;
133 return false;
134 }
135
136 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
137 // classes for primitives and arrays and vm anonymous classes cannot be redefined
138 // check here so following code can assume these classes are InstanceKlass
139 if (!is_modifiable_class(mirror)) {
140 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
141 return false;
142 }
143 }
144
145 // Start timer after all the sanity checks; not quite accurate, but
146 // better than adding a bunch of stop() calls.
147 if (log_is_enabled(Info, redefine, class, timer)) {
148 _timer_vm_op_prologue.start();
149 }
150
151 lock_classes();
152 // We first load new class versions in the prologue, because somewhere down the
153 // call chain it is required that the current thread is a Java thread.
154 _res = load_new_class_versions(Thread::current());
155 if (_res != JVMTI_ERROR_NONE) {
156 // free any successfully created classes, since none are redefined
157 for (int i = 0; i < _class_count; i++) {
158 if (_scratch_classes[i] != NULL) {
159 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
160 // Free the memory for this class at class unloading time. Not before
161 // because CMS might think this is still live.
162 InstanceKlass* ik = get_ik(_class_defs[i].klass);
163 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
164 // Don't double-free cached_class_file copied from the original class if error.
165 _scratch_classes[i]->set_cached_class_file(NULL);
166 }
167 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
168 }
169 }
170 // Free os::malloc allocated memory in load_new_class_version.
171 os::free(_scratch_classes);
172 _timer_vm_op_prologue.stop();
173 unlock_classes();
174 return false;
175 }
176
177 _timer_vm_op_prologue.stop();
178 return true;
179 }
180
181 void VM_RedefineClasses::doit() {
182 Thread *thread = Thread::current();
183
184 #if INCLUDE_CDS
185 if (UseSharedSpaces) {
186 // Sharing is enabled so we remap the shared readonly space to
187 // shared readwrite, private just in case we need to redefine
188 // a shared class. We do the remap during the doit() phase of
189 // the safepoint to be safer.
190 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
191 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
192 _res = JVMTI_ERROR_INTERNAL;
193 return;
194 }
195 }
196 #endif
197
198 // Mark methods seen on stack and everywhere else so old methods are not
199 // cleaned up if they're on the stack.
200 MetadataOnStackMark md_on_stack(true);
201 HandleMark hm(thread); // make sure any handles created are deleted
202 // before the stack walk again.
203
204 for (int i = 0; i < _class_count; i++) {
205 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
206 }
207
208 // Clean out MethodData pointing to old Method*
209 // Have to do this after all classes are redefined and all methods that
210 // are redefined are marked as old.
211 MethodDataCleaner clean_weak_method_links;
212 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
213
214 // JSR-292 support
215 if (_any_class_has_resolved_methods) {
216 bool trace_name_printed = false;
217 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
218 }
219
220 // Disable any dependent concurrent compilations
221 SystemDictionary::notice_modification();
222
223 // Set flag indicating that some invariants are no longer true.
224 // See jvmtiExport.hpp for detailed explanation.
225 JvmtiExport::set_has_redefined_a_class();
226
227 // check_class() is optionally called for product bits, but is
228 // always called for non-product bits.
229 #ifdef PRODUCT
230 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
231 #endif
232 log_trace(redefine, class, obsolete, metadata)("calling check_class");
233 CheckClass check_class(thread);
234 ClassLoaderDataGraph::classes_do(&check_class);
235 #ifdef PRODUCT
236 }
237 #endif
238 }
239
240 void VM_RedefineClasses::doit_epilogue() {
241 unlock_classes();
242
243 // Free os::malloc allocated memory.
244 os::free(_scratch_classes);
245
246 // Reset the_class to null for error printing.
247 _the_class = NULL;
248
249 if (log_is_enabled(Info, redefine, class, timer)) {
250 // Used to have separate timers for "doit" and "all", but the timer
251 // overhead skewed the measurements.
252 julong doit_time = _timer_rsc_phase1.milliseconds() +
253 _timer_rsc_phase2.milliseconds();
254 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
255
256 log_info(redefine, class, timer)
257 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
258 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
259 log_info(redefine, class, timer)
260 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
261 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
262 }
263 }
264
265 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
266 // classes for primitives cannot be redefined
267 if (java_lang_Class::is_primitive(klass_mirror)) {
268 return false;
269 }
270 Klass* k = java_lang_Class::as_Klass(klass_mirror);
271 // classes for arrays cannot be redefined
272 if (k == NULL || !k->is_instance_klass()) {
273 return false;
274 }
275
276 // Cannot redefine or retransform an anonymous class.
277 if (InstanceKlass::cast(k)->is_anonymous()) {
278 return false;
279 }
280 return true;
281 }
282
283 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
284 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
285 // direct CP entries, there is just the current entry to append. For
286 // indirect and double-indirect CP entries, there are zero or more
287 // referenced CP entries along with the current entry to append.
288 // Indirect and double-indirect CP entries are handled by recursive
289 // calls to append_entry() as needed. The referenced CP entries are
290 // always appended to *merge_cp_p before the referee CP entry. These
291 // referenced CP entries may already exist in *merge_cp_p in which case
292 // there is nothing extra to append and only the current entry is
293 // appended.
294 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
295 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
296 TRAPS) {
297
298 // append is different depending on entry tag type
299 switch (scratch_cp->tag_at(scratch_i).value()) {
300
301 // The old verifier is implemented outside the VM. It loads classes,
302 // but does not resolve constant pool entries directly so we never
303 // see Class entries here with the old verifier. Similarly the old
304 // verifier does not like Class entries in the input constant pool.
305 // The split-verifier is implemented in the VM so it can optionally
306 // and directly resolve constant pool entries to load classes. The
307 // split-verifier can accept either Class entries or UnresolvedClass
308 // entries in the input constant pool. We revert the appended copy
309 // back to UnresolvedClass so that either verifier will be happy
310 // with the constant pool entry.
311 //
312 // this is an indirect CP entry so it needs special handling
313 case JVM_CONSTANT_Class:
314 case JVM_CONSTANT_UnresolvedClass:
315 {
316 int name_i = scratch_cp->klass_name_index_at(scratch_i);
317 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
318 merge_cp_length_p, THREAD);
319
320 if (new_name_i != name_i) {
321 log_trace(redefine, class, constantpool)
322 ("Class entry@%d name_index change: %d to %d",
323 *merge_cp_length_p, name_i, new_name_i);
324 }
325
326 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
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)++;
333 } break;
334
335 // this is an indirect CP entry so it needs special handling
336 case JVM_CONSTANT_Value:
337 case JVM_CONSTANT_UnresolvedValue:
338 {
339 int name_i = scratch_cp->klass_name_index_at(scratch_i);
340 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
341 merge_cp_length_p, THREAD);
342
343 if (new_name_i != name_i) {
344 log_trace(redefine, class, constantpool)
345 ("Value type entry@%d name_index change: %d to %d",
346 *merge_cp_length_p, name_i, new_name_i);
347 }
348
349 (*merge_cp_p)->temp_unresolved_value_type_at_put(*merge_cp_length_p, new_name_i);
350 if (scratch_i != *merge_cp_length_p) {
351 // The new entry in *merge_cp_p is at a different index than
352 // the new entry in scratch_cp so we need to map the index values.
353 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
354 }
355 (*merge_cp_length_p)++;
356 } break;
357
358 // these are direct CP entries so they can be directly appended,
359 // but double and long take two constant pool entries
360 case JVM_CONSTANT_Double: // fall through
361 case JVM_CONSTANT_Long:
362 {
363 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
364 THREAD);
365
366 if (scratch_i != *merge_cp_length_p) {
367 // The new entry in *merge_cp_p is at a different index than
368 // the new entry in scratch_cp so we need to map the index values.
369 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
370 }
371 (*merge_cp_length_p) += 2;
372 } break;
373
374 // these are direct CP entries so they can be directly appended
375 case JVM_CONSTANT_Float: // fall through
376 case JVM_CONSTANT_Integer: // fall through
377 case JVM_CONSTANT_Utf8: // fall through
378
379 // This was an indirect CP entry, but it has been changed into
380 // Symbol*s so this entry can be directly appended.
381 case JVM_CONSTANT_String: // fall through
382 {
383 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
384 THREAD);
385
386 if (scratch_i != *merge_cp_length_p) {
387 // The new entry in *merge_cp_p is at a different index than
388 // the new entry in scratch_cp so we need to map the index values.
389 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
390 }
391 (*merge_cp_length_p)++;
392 } break;
393
394 // this is an indirect CP entry so it needs special handling
395 case JVM_CONSTANT_NameAndType:
396 {
397 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
398 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
399 merge_cp_length_p, THREAD);
400
401 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
402 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
403 merge_cp_p, merge_cp_length_p,
404 THREAD);
405
406 // If the referenced entries already exist in *merge_cp_p, then
407 // both new_name_ref_i and new_signature_ref_i will both be 0.
408 // In that case, all we are appending is the current entry.
409 if (new_name_ref_i != name_ref_i) {
410 log_trace(redefine, class, constantpool)
411 ("NameAndType entry@%d name_ref_index change: %d to %d",
412 *merge_cp_length_p, name_ref_i, new_name_ref_i);
413 }
414 if (new_signature_ref_i != signature_ref_i) {
415 log_trace(redefine, class, constantpool)
416 ("NameAndType entry@%d signature_ref_index change: %d to %d",
417 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
418 }
419
420 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
421 new_name_ref_i, new_signature_ref_i);
422 if (scratch_i != *merge_cp_length_p) {
423 // The new entry in *merge_cp_p is at a different index than
424 // the new entry in scratch_cp so we need to map the index values.
425 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
426 }
427 (*merge_cp_length_p)++;
428 } break;
429
430 // this is a double-indirect CP entry so it needs special handling
431 case JVM_CONSTANT_Fieldref: // fall through
432 case JVM_CONSTANT_InterfaceMethodref: // fall through
433 case JVM_CONSTANT_Methodref:
434 {
435 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
436 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
437 merge_cp_p, merge_cp_length_p, THREAD);
438
439 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
440 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
441 merge_cp_p, merge_cp_length_p, THREAD);
442
443 const char *entry_name = NULL;
444 switch (scratch_cp->tag_at(scratch_i).value()) {
445 case JVM_CONSTANT_Fieldref:
446 entry_name = "Fieldref";
447 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
448 new_name_and_type_ref_i);
449 break;
450 case JVM_CONSTANT_InterfaceMethodref:
451 entry_name = "IFMethodref";
452 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
453 new_klass_ref_i, new_name_and_type_ref_i);
454 break;
455 case JVM_CONSTANT_Methodref:
456 entry_name = "Methodref";
457 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
458 new_name_and_type_ref_i);
459 break;
460 default:
461 guarantee(false, "bad switch");
462 break;
463 }
464
465 if (klass_ref_i != new_klass_ref_i) {
466 log_trace(redefine, class, constantpool)
467 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
468 }
469 if (name_and_type_ref_i != new_name_and_type_ref_i) {
470 log_trace(redefine, class, constantpool)
471 ("%s entry@%d name_and_type_index changed: %d to %d",
472 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
473 }
474
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_MethodType:
485 {
486 int ref_i = scratch_cp->method_type_index_at(scratch_i);
487 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
488 merge_cp_length_p, THREAD);
489 if (new_ref_i != ref_i) {
490 log_trace(redefine, class, constantpool)
491 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
492 }
493 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
494 if (scratch_i != *merge_cp_length_p) {
495 // The new entry in *merge_cp_p is at a different index than
496 // the new entry in scratch_cp so we need to map the index values.
497 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
498 }
499 (*merge_cp_length_p)++;
500 } break;
501
502 // this is an indirect CP entry so it needs special handling
503 case JVM_CONSTANT_MethodHandle:
504 {
505 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
506 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
507 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
508 merge_cp_length_p, THREAD);
509 if (new_ref_i != ref_i) {
510 log_trace(redefine, class, constantpool)
511 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
512 }
513 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
514 if (scratch_i != *merge_cp_length_p) {
515 // The new entry in *merge_cp_p is at a different index than
516 // the new entry in scratch_cp so we need to map the index values.
517 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
518 }
519 (*merge_cp_length_p)++;
520 } break;
521
522 // this is an indirect CP entry so it needs special handling
523 case JVM_CONSTANT_Dynamic: // fall through
524 case JVM_CONSTANT_InvokeDynamic:
525 {
526 // Index of the bootstrap specifier in the operands array
527 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
528 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
529 merge_cp_length_p, THREAD);
530 // The bootstrap method NameAndType_info index
531 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
532 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
533 merge_cp_length_p, THREAD);
534 if (new_bs_i != old_bs_i) {
535 log_trace(redefine, class, constantpool)
536 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
537 *merge_cp_length_p, old_bs_i, new_bs_i);
538 }
539 if (new_ref_i != old_ref_i) {
540 log_trace(redefine, class, constantpool)
541 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
542 }
543
544 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
545 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
546 else
547 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
548 if (scratch_i != *merge_cp_length_p) {
549 // The new entry in *merge_cp_p is at a different index than
550 // the new entry in scratch_cp so we need to map the index values.
551 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
552 }
553 (*merge_cp_length_p)++;
554 } break;
555
556 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
557 // ClassIndex
558 case JVM_CONSTANT_ClassIndex: // fall through
559 case JVM_CONSTANT_ValueIndex: // fall through
560
561 // Invalid is used as the tag for the second constant pool entry
562 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
563 // not be seen by itself.
564 case JVM_CONSTANT_Invalid: // fall through
565
566 // At this stage, String could be here, but not StringIndex
567 case JVM_CONSTANT_StringIndex: // fall through
568
569 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be here
570 case JVM_CONSTANT_UnresolvedClassInError: // fall through
571
572 // At this stage JVM_CONSTANT_UnresolvedValueInError should not be here
573 case JVM_CONSTANT_UnresolvedValueInError: // fall through
574
575 default:
576 {
577 // leave a breadcrumb
578 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
579 ShouldNotReachHere();
580 } break;
581 } // end switch tag value
582 } // end append_entry()
583
584
585 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
586 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
587
588 int new_ref_i = ref_i;
589 bool match = (ref_i < *merge_cp_length_p) &&
590 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
591
592 if (!match) {
593 // forward reference in *merge_cp_p or not a direct match
594 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
595 if (found_i != 0) {
596 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
597 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
598 new_ref_i = found_i;
599 map_index(scratch_cp, ref_i, found_i);
600 } else {
601 // no match found so we have to append this entry to *merge_cp_p
602 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
603 // The above call to append_entry() can only append one entry
604 // so the post call query of *merge_cp_length_p is only for
605 // the sake of consistency.
606 new_ref_i = *merge_cp_length_p - 1;
607 }
608 }
609
610 return new_ref_i;
611 } // end find_or_append_indirect_entry()
612
613
614 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
615 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
616 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
617 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
618 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
619
620 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
621 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
622 merge_cp_length_p, THREAD);
623 if (new_ref_i != old_ref_i) {
624 log_trace(redefine, class, constantpool)
625 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
626 }
627
628 Array<u2>* merge_ops = (*merge_cp_p)->operands();
629 int new_bs_i = _operands_cur_length;
630 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
631 // However, the operand_offset_at(0) was set in the extend_operands() call.
632 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
633 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
634 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
635
636 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
637 merge_ops->at_put(new_base++, new_ref_i);
638 merge_ops->at_put(new_base++, argc);
639
640 for (int i = 0; i < argc; i++) {
641 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
642 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
643 merge_cp_length_p, THREAD);
644 merge_ops->at_put(new_base++, new_arg_ref_i);
645 if (new_arg_ref_i != old_arg_ref_i) {
646 log_trace(redefine, class, constantpool)
647 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
648 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
649 }
650 }
651 if (old_bs_i != _operands_cur_length) {
652 // The bootstrap specifier in *merge_cp_p is at a different index than
653 // that in scratch_cp so we need to map the index values.
654 map_operand_index(old_bs_i, new_bs_i);
655 }
656 _operands_cur_length++;
657 } // end append_operand()
658
659
660 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
661 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
662
663 int new_bs_i = old_bs_i; // bootstrap specifier index
664 bool match = (old_bs_i < _operands_cur_length) &&
665 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
666
667 if (!match) {
668 // forward reference in *merge_cp_p or not a direct match
669 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
670 _operands_cur_length, THREAD);
671 if (found_i != -1) {
672 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
673 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
674 new_bs_i = found_i;
675 map_operand_index(old_bs_i, found_i);
676 } else {
677 // no match found so we have to append this bootstrap specifier to *merge_cp_p
678 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
679 new_bs_i = _operands_cur_length - 1;
680 }
681 }
682 return new_bs_i;
683 } // end find_or_append_operand()
684
685
686 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
687 if (merge_cp->operands() == NULL) {
688 return;
689 }
690 // Shrink the merge_cp operands
691 merge_cp->shrink_operands(_operands_cur_length, CHECK);
692
693 if (log_is_enabled(Trace, redefine, class, constantpool)) {
694 // don't want to loop unless we are tracing
695 int count = 0;
696 for (int i = 1; i < _operands_index_map_p->length(); i++) {
697 int value = _operands_index_map_p->at(i);
698 if (value != -1) {
699 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
700 count++;
701 }
702 }
703 }
704 // Clean-up
705 _operands_index_map_p = NULL;
706 _operands_cur_length = 0;
707 _operands_index_map_count = 0;
708 } // end finalize_operands_merge()
709
710
711 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
712 InstanceKlass* the_class,
713 InstanceKlass* scratch_class) {
714 int i;
715
716 // Check superclasses, or rather their names, since superclasses themselves can be
717 // requested to replace.
718 // Check for NULL superclass first since this might be java.lang.Object
719 if (the_class->super() != scratch_class->super() &&
720 (the_class->super() == NULL || scratch_class->super() == NULL ||
721 the_class->super()->name() !=
722 scratch_class->super()->name())) {
723 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
724 }
725
726 // Check if the number, names and order of directly implemented interfaces are the same.
727 // I think in principle we should just check if the sets of names of directly implemented
728 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
729 // .java file, also changes in .class file) should not matter. However, comparing sets is
730 // technically a bit more difficult, and, more importantly, I am not sure at present that the
731 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
732 // rely on it somewhere.
733 Array<Klass*>* k_interfaces = the_class->local_interfaces();
734 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
735 int n_intfs = k_interfaces->length();
736 if (n_intfs != k_new_interfaces->length()) {
737 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
738 }
739 for (i = 0; i < n_intfs; i++) {
740 if (k_interfaces->at(i)->name() !=
741 k_new_interfaces->at(i)->name()) {
742 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
743 }
744 }
745
746 // Check whether class is in the error init state.
747 if (the_class->is_in_error_state()) {
748 // TBD #5057930: special error code is needed in 1.6
749 return JVMTI_ERROR_INVALID_CLASS;
750 }
751
752 // Check whether class modifiers are the same.
753 jushort old_flags = (jushort) the_class->access_flags().get_flags();
754 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
755 if (old_flags != new_flags) {
756 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
757 }
758
759 // Check if the number, names, types and order of fields declared in these classes
760 // are the same.
761 JavaFieldStream old_fs(the_class);
762 JavaFieldStream new_fs(scratch_class);
763 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
764 // access
765 old_flags = old_fs.access_flags().as_short();
766 new_flags = new_fs.access_flags().as_short();
767 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
768 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
769 }
770 // offset
771 if (old_fs.offset() != new_fs.offset()) {
772 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
773 }
774 // name and signature
775 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
776 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
777 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
778 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
779 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
780 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
781 }
782 }
783
784 // If both streams aren't done then we have a differing number of
785 // fields.
786 if (!old_fs.done() || !new_fs.done()) {
787 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
788 }
789
790 // Do a parallel walk through the old and new methods. Detect
791 // cases where they match (exist in both), have been added in
792 // the new methods, or have been deleted (exist only in the
793 // old methods). The class file parser places methods in order
794 // by method name, but does not order overloaded methods by
795 // signature. In order to determine what fate befell the methods,
796 // this code places the overloaded new methods that have matching
797 // old methods in the same order as the old methods and places
798 // new overloaded methods at the end of overloaded methods of
799 // that name. The code for this order normalization is adapted
800 // from the algorithm used in InstanceKlass::find_method().
801 // Since we are swapping out of order entries as we find them,
802 // we only have to search forward through the overloaded methods.
803 // Methods which are added and have the same name as an existing
804 // method (but different signature) will be put at the end of
805 // the methods with that name, and the name mismatch code will
806 // handle them.
807 Array<Method*>* k_old_methods(the_class->methods());
808 Array<Method*>* k_new_methods(scratch_class->methods());
809 int n_old_methods = k_old_methods->length();
810 int n_new_methods = k_new_methods->length();
811 Thread* thread = Thread::current();
812
813 int ni = 0;
814 int oi = 0;
815 while (true) {
816 Method* k_old_method;
817 Method* k_new_method;
818 enum { matched, added, deleted, undetermined } method_was = undetermined;
819
820 if (oi >= n_old_methods) {
821 if (ni >= n_new_methods) {
822 break; // we've looked at everything, done
823 }
824 // New method at the end
825 k_new_method = k_new_methods->at(ni);
826 method_was = added;
827 } else if (ni >= n_new_methods) {
828 // Old method, at the end, is deleted
829 k_old_method = k_old_methods->at(oi);
830 method_was = deleted;
831 } else {
832 // There are more methods in both the old and new lists
833 k_old_method = k_old_methods->at(oi);
834 k_new_method = k_new_methods->at(ni);
835 if (k_old_method->name() != k_new_method->name()) {
836 // Methods are sorted by method name, so a mismatch means added
837 // or deleted
838 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
839 method_was = added;
840 } else {
841 method_was = deleted;
842 }
843 } else if (k_old_method->signature() == k_new_method->signature()) {
844 // Both the name and signature match
845 method_was = matched;
846 } else {
847 // The name matches, but the signature doesn't, which means we have to
848 // search forward through the new overloaded methods.
849 int nj; // outside the loop for post-loop check
850 for (nj = ni + 1; nj < n_new_methods; nj++) {
851 Method* m = k_new_methods->at(nj);
852 if (k_old_method->name() != m->name()) {
853 // reached another method name so no more overloaded methods
854 method_was = deleted;
855 break;
856 }
857 if (k_old_method->signature() == m->signature()) {
858 // found a match so swap the methods
859 k_new_methods->at_put(ni, m);
860 k_new_methods->at_put(nj, k_new_method);
861 k_new_method = m;
862 method_was = matched;
863 break;
864 }
865 }
866
867 if (nj >= n_new_methods) {
868 // reached the end without a match; so method was deleted
869 method_was = deleted;
870 }
871 }
872 }
873
874 switch (method_was) {
875 case matched:
876 // methods match, be sure modifiers do too
877 old_flags = (jushort) k_old_method->access_flags().get_flags();
878 new_flags = (jushort) k_new_method->access_flags().get_flags();
879 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
880 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
881 }
882 {
883 u2 new_num = k_new_method->method_idnum();
884 u2 old_num = k_old_method->method_idnum();
885 if (new_num != old_num) {
886 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
887 if (idnum_owner != NULL) {
888 // There is already a method assigned this idnum -- switch them
889 // Take current and original idnum from the new_method
890 idnum_owner->set_method_idnum(new_num);
891 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
892 }
893 // Take current and original idnum from the old_method
894 k_new_method->set_method_idnum(old_num);
895 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
896 if (thread->has_pending_exception()) {
897 return JVMTI_ERROR_OUT_OF_MEMORY;
898 }
899 }
900 }
901 log_trace(redefine, class, normalize)
902 ("Method matched: new: %s [%d] == old: %s [%d]",
903 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
904 // advance to next pair of methods
905 ++oi;
906 ++ni;
907 break;
908 case added:
909 // method added, see if it is OK
910 new_flags = (jushort) k_new_method->access_flags().get_flags();
911 if ((new_flags & JVM_ACC_PRIVATE) == 0
912 // hack: private should be treated as final, but alas
913 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
914 ) {
915 // new methods must be private
916 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
917 }
918 {
919 u2 num = the_class->next_method_idnum();
920 if (num == ConstMethod::UNSET_IDNUM) {
921 // cannot add any more methods
922 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
923 }
924 u2 new_num = k_new_method->method_idnum();
925 Method* idnum_owner = scratch_class->method_with_idnum(num);
926 if (idnum_owner != NULL) {
927 // There is already a method assigned this idnum -- switch them
928 // Take current and original idnum from the new_method
929 idnum_owner->set_method_idnum(new_num);
930 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
931 }
932 k_new_method->set_method_idnum(num);
933 k_new_method->set_orig_method_idnum(num);
934 if (thread->has_pending_exception()) {
935 return JVMTI_ERROR_OUT_OF_MEMORY;
936 }
937 }
938 log_trace(redefine, class, normalize)
939 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
940 ++ni; // advance to next new method
941 break;
942 case deleted:
943 // method deleted, see if it is OK
944 old_flags = (jushort) k_old_method->access_flags().get_flags();
945 if ((old_flags & JVM_ACC_PRIVATE) == 0
946 // hack: private should be treated as final, but alas
947 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
948 ) {
949 // deleted methods must be private
950 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
951 }
952 log_trace(redefine, class, normalize)
953 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
954 ++oi; // advance to next old method
955 break;
956 default:
957 ShouldNotReachHere();
958 }
959 }
960
961 return JVMTI_ERROR_NONE;
962 }
963
964
965 // Find new constant pool index value for old constant pool index value
966 // by seaching the index map. Returns zero (0) if there is no mapped
967 // value for the old constant pool index.
968 int VM_RedefineClasses::find_new_index(int old_index) {
969 if (_index_map_count == 0) {
970 // map is empty so nothing can be found
971 return 0;
972 }
973
974 if (old_index < 1 || old_index >= _index_map_p->length()) {
975 // The old_index is out of range so it is not mapped. This should
976 // not happen in regular constant pool merging use, but it can
977 // happen if a corrupt annotation is processed.
978 return 0;
979 }
980
981 int value = _index_map_p->at(old_index);
982 if (value == -1) {
983 // the old_index is not mapped
984 return 0;
985 }
986
987 return value;
988 } // end find_new_index()
989
990
991 // Find new bootstrap specifier index value for old bootstrap specifier index
992 // value by seaching the index map. Returns unused index (-1) if there is
993 // no mapped value for the old bootstrap specifier index.
994 int VM_RedefineClasses::find_new_operand_index(int old_index) {
995 if (_operands_index_map_count == 0) {
996 // map is empty so nothing can be found
997 return -1;
998 }
999
1000 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1001 // The old_index is out of range so it is not mapped.
1002 // This should not happen in regular constant pool merging use.
1003 return -1;
1004 }
1005
1006 int value = _operands_index_map_p->at(old_index);
1007 if (value == -1) {
1008 // the old_index is not mapped
1009 return -1;
1010 }
1011
1012 return value;
1013 } // end find_new_operand_index()
1014
1015
1016 // Returns true if the current mismatch is due to a resolved/unresolved
1017 // class pair. Otherwise, returns false.
1018 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
1019 int index1, const constantPoolHandle& cp2, int index2) {
1020
1021 jbyte t1 = cp1->tag_at(index1).value();
1022 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass &&
1023 t1 != JVM_CONSTANT_Value && t1 != JVM_CONSTANT_UnresolvedValue) {
1024 return false; // wrong entry type; not our special case
1025 }
1026
1027 jbyte t2 = cp2->tag_at(index2).value();
1028 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass &&
1029 t2 != JVM_CONSTANT_Value && t2 != JVM_CONSTANT_UnresolvedValue) {
1030 return false; // wrong entry type; not our special case
1031 }
1032
1033 if (t1 == t2) {
1034 return false; // not a mismatch; not our special case
1035 }
1036
1037 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1038 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1039 if (strcmp(s1, s2) != 0) {
1040 return false; // strings don't match; not our special case
1041 }
1042
1043 return true; // made it through the gauntlet; this is our special case
1044 } // end is_unresolved_class_mismatch()
1045
1046
1047 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1048
1049 // For consistency allocate memory using os::malloc wrapper.
1050 _scratch_classes = (InstanceKlass**)
1051 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1052 if (_scratch_classes == NULL) {
1053 return JVMTI_ERROR_OUT_OF_MEMORY;
1054 }
1055 // Zero initialize the _scratch_classes array.
1056 for (int i = 0; i < _class_count; i++) {
1057 _scratch_classes[i] = NULL;
1058 }
1059
1060 ResourceMark rm(THREAD);
1061
1062 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1063 // state can only be NULL if the current thread is exiting which
1064 // should not happen since we're trying to do a RedefineClasses
1065 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1066 for (int i = 0; i < _class_count; i++) {
1067 // Create HandleMark so that any handles created while loading new class
1068 // versions are deleted. Constant pools are deallocated while merging
1069 // constant pools
1070 HandleMark hm(THREAD);
1071 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1072 Symbol* the_class_sym = the_class->name();
1073
1074 log_debug(redefine, class, load)
1075 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1076 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1077
1078 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1079 _class_defs[i].class_byte_count,
1080 "__VM_RedefineClasses__",
1081 ClassFileStream::verify);
1082
1083 // Parse the stream.
1084 Handle the_class_loader(THREAD, the_class->class_loader());
1085 Handle protection_domain(THREAD, the_class->protection_domain());
1086 // Set redefined class handle in JvmtiThreadState class.
1087 // This redefined class is sent to agent event handler for class file
1088 // load hook event.
1089 state->set_class_being_redefined(the_class, _class_load_kind);
1090
1091 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1092 the_class_sym,
1093 the_class_loader,
1094 protection_domain,
1095 &st,
1096 THREAD);
1097 // Clear class_being_redefined just to be sure.
1098 state->clear_class_being_redefined();
1099
1100 // TODO: if this is retransform, and nothing changed we can skip it
1101
1102 // Need to clean up allocated InstanceKlass if there's an error so assign
1103 // the result here. Caller deallocates all the scratch classes in case of
1104 // an error.
1105 _scratch_classes[i] = scratch_class;
1106
1107 if (HAS_PENDING_EXCEPTION) {
1108 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1109 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1110 CLEAR_PENDING_EXCEPTION;
1111
1112 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1113 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1114 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1115 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1116 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1117 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1118 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1119 // The message will be "XXX (wrong name: YYY)"
1120 return JVMTI_ERROR_NAMES_DONT_MATCH;
1121 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1122 return JVMTI_ERROR_OUT_OF_MEMORY;
1123 } else { // Just in case more exceptions can be thrown..
1124 return JVMTI_ERROR_FAILS_VERIFICATION;
1125 }
1126 }
1127
1128 // Ensure class is linked before redefine
1129 if (!the_class->is_linked()) {
1130 the_class->link_class(THREAD);
1131 if (HAS_PENDING_EXCEPTION) {
1132 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1133 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1134 CLEAR_PENDING_EXCEPTION;
1135 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1136 return JVMTI_ERROR_OUT_OF_MEMORY;
1137 } else {
1138 return JVMTI_ERROR_INTERNAL;
1139 }
1140 }
1141 }
1142
1143 // Do the validity checks in compare_and_normalize_class_versions()
1144 // before verifying the byte codes. By doing these checks first, we
1145 // limit the number of functions that require redirection from
1146 // the_class to scratch_class. In particular, we don't have to
1147 // modify JNI GetSuperclass() and thus won't change its performance.
1148 jvmtiError res = compare_and_normalize_class_versions(the_class,
1149 scratch_class);
1150 if (res != JVMTI_ERROR_NONE) {
1151 return res;
1152 }
1153
1154 // verify what the caller passed us
1155 {
1156 // The bug 6214132 caused the verification to fail.
1157 // Information about the_class and scratch_class is temporarily
1158 // recorded into jvmtiThreadState. This data is used to redirect
1159 // the_class to scratch_class in the JVM_* functions called by the
1160 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1161 // description.
1162 RedefineVerifyMark rvm(the_class, scratch_class, state);
1163 Verifier::verify(
1164 scratch_class, Verifier::ThrowException, true, THREAD);
1165 }
1166
1167 if (HAS_PENDING_EXCEPTION) {
1168 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1169 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1170 CLEAR_PENDING_EXCEPTION;
1171 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1172 return JVMTI_ERROR_OUT_OF_MEMORY;
1173 } else {
1174 // tell the caller the bytecodes are bad
1175 return JVMTI_ERROR_FAILS_VERIFICATION;
1176 }
1177 }
1178
1179 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1180 if (HAS_PENDING_EXCEPTION) {
1181 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1182 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1183 CLEAR_PENDING_EXCEPTION;
1184 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1185 return JVMTI_ERROR_OUT_OF_MEMORY;
1186 } else {
1187 return JVMTI_ERROR_INTERNAL;
1188 }
1189 }
1190
1191 if (VerifyMergedCPBytecodes) {
1192 // verify what we have done during constant pool merging
1193 {
1194 RedefineVerifyMark rvm(the_class, scratch_class, state);
1195 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1196 }
1197
1198 if (HAS_PENDING_EXCEPTION) {
1199 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1200 log_info(redefine, class, load, exceptions)
1201 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1202 CLEAR_PENDING_EXCEPTION;
1203 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1204 return JVMTI_ERROR_OUT_OF_MEMORY;
1205 } else {
1206 // tell the caller that constant pool merging screwed up
1207 return JVMTI_ERROR_INTERNAL;
1208 }
1209 }
1210 }
1211
1212 Rewriter::rewrite(scratch_class, THREAD);
1213 if (!HAS_PENDING_EXCEPTION) {
1214 scratch_class->link_methods(THREAD);
1215 }
1216 if (HAS_PENDING_EXCEPTION) {
1217 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1218 log_info(redefine, class, load, exceptions)
1219 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1220 CLEAR_PENDING_EXCEPTION;
1221 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1222 return JVMTI_ERROR_OUT_OF_MEMORY;
1223 } else {
1224 return JVMTI_ERROR_INTERNAL;
1225 }
1226 }
1227
1228 log_debug(redefine, class, load)
1229 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1230 }
1231
1232 return JVMTI_ERROR_NONE;
1233 }
1234
1235
1236 // Map old_index to new_index as needed. scratch_cp is only needed
1237 // for log calls.
1238 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1239 int old_index, int new_index) {
1240 if (find_new_index(old_index) != 0) {
1241 // old_index is already mapped
1242 return;
1243 }
1244
1245 if (old_index == new_index) {
1246 // no mapping is needed
1247 return;
1248 }
1249
1250 _index_map_p->at_put(old_index, new_index);
1251 _index_map_count++;
1252
1253 log_trace(redefine, class, constantpool)
1254 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1255 } // end map_index()
1256
1257
1258 // Map old_index to new_index as needed.
1259 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1260 if (find_new_operand_index(old_index) != -1) {
1261 // old_index is already mapped
1262 return;
1263 }
1264
1265 if (old_index == new_index) {
1266 // no mapping is needed
1267 return;
1268 }
1269
1270 _operands_index_map_p->at_put(old_index, new_index);
1271 _operands_index_map_count++;
1272
1273 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1274 } // end map_index()
1275
1276
1277 // Merge old_cp and scratch_cp and return the results of the merge via
1278 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1279 // merge_cp_length_p. The entries in old_cp occupy the same locations
1280 // in *merge_cp_p. Also creates a map of indices from entries in
1281 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1282 // entries are only created for entries in scratch_cp that occupy a
1283 // different location in *merged_cp_p.
1284 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1285 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1286 int *merge_cp_length_p, TRAPS) {
1287
1288 if (merge_cp_p == NULL) {
1289 assert(false, "caller must provide scratch constantPool");
1290 return false; // robustness
1291 }
1292 if (merge_cp_length_p == NULL) {
1293 assert(false, "caller must provide scratch CP length");
1294 return false; // robustness
1295 }
1296 // Worst case we need old_cp->length() + scratch_cp()->length(),
1297 // but the caller might be smart so make sure we have at least
1298 // the minimum.
1299 if ((*merge_cp_p)->length() < old_cp->length()) {
1300 assert(false, "merge area too small");
1301 return false; // robustness
1302 }
1303
1304 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1305
1306 {
1307 // Pass 0:
1308 // The old_cp is copied to *merge_cp_p; this means that any code
1309 // using old_cp does not have to change. This work looks like a
1310 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1311 // handle one special case:
1312 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1313 // - revert JVM_CONSTANT_Value to JVM_CONSTANT_UnresolvedValue
1314 // This will make verification happy.
1315
1316 int old_i; // index into old_cp
1317
1318 // index zero (0) is not used in constantPools
1319 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1320 // leave debugging crumb
1321 jbyte old_tag = old_cp->tag_at(old_i).value();
1322 switch (old_tag) {
1323 case JVM_CONSTANT_Class:
1324 case JVM_CONSTANT_UnresolvedClass:
1325 // revert the copy to JVM_CONSTANT_UnresolvedClass
1326 // May be resolving while calling this so do the same for
1327 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1328 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1329 old_cp->klass_name_index_at(old_i));
1330 break;
1331
1332 case JVM_CONSTANT_Value:
1333 case JVM_CONSTANT_UnresolvedValue:
1334 // revert the copy to JVM_CONSTANT_UnresolvedValue
1335 // May be resolving while calling this so do the same for
1336 // JVM_CONSTANT_UnresolvedValue (klass_name_at() deals with transition)
1337 (*merge_cp_p)->temp_unresolved_value_type_at_put(old_i,
1338 old_cp->klass_name_index_at(old_i));
1339 break;
1340
1341 case JVM_CONSTANT_Double:
1342 case JVM_CONSTANT_Long:
1343 // just copy the entry to *merge_cp_p, but double and long take
1344 // two constant pool entries
1345 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1346 old_i++;
1347 break;
1348
1349 default:
1350 // just copy the entry to *merge_cp_p
1351 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1352 break;
1353 }
1354 } // end for each old_cp entry
1355
1356 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1357 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1358
1359 // We don't need to sanity check that *merge_cp_length_p is within
1360 // *merge_cp_p bounds since we have the minimum on-entry check above.
1361 (*merge_cp_length_p) = old_i;
1362 }
1363
1364 // merge_cp_len should be the same as old_cp->length() at this point
1365 // so this trace message is really a "warm-and-breathing" message.
1366 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1367
1368 int scratch_i; // index into scratch_cp
1369 {
1370 // Pass 1a:
1371 // Compare scratch_cp entries to the old_cp entries that we have
1372 // already copied to *merge_cp_p. In this pass, we are eliminating
1373 // exact duplicates (matching entry at same index) so we only
1374 // compare entries in the common indice range.
1375 int increment = 1;
1376 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1377 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1378 switch (scratch_cp->tag_at(scratch_i).value()) {
1379 case JVM_CONSTANT_Double:
1380 case JVM_CONSTANT_Long:
1381 // double and long take two constant pool entries
1382 increment = 2;
1383 break;
1384
1385 default:
1386 increment = 1;
1387 break;
1388 }
1389
1390 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1391 scratch_i, CHECK_0);
1392 if (match) {
1393 // found a match at the same index so nothing more to do
1394 continue;
1395 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1396 *merge_cp_p, scratch_i)) {
1397 // The mismatch in compare_entry_to() above is because of a
1398 // resolved versus unresolved class entry at the same index
1399 // with the same string value. Since Pass 0 reverted any
1400 // class entries to unresolved class entries in *merge_cp_p,
1401 // we go with the unresolved class entry.
1402 continue;
1403 }
1404
1405 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1406 CHECK_0);
1407 if (found_i != 0) {
1408 guarantee(found_i != scratch_i,
1409 "compare_entry_to() and find_matching_entry() do not agree");
1410
1411 // Found a matching entry somewhere else in *merge_cp_p so
1412 // just need a mapping entry.
1413 map_index(scratch_cp, scratch_i, found_i);
1414 continue;
1415 }
1416
1417 // The find_matching_entry() call above could fail to find a match
1418 // due to a resolved versus unresolved class or string entry situation
1419 // like we solved above with the is_unresolved_*_mismatch() calls.
1420 // However, we would have to call is_unresolved_*_mismatch() over
1421 // all of *merge_cp_p (potentially) and that doesn't seem to be
1422 // worth the time.
1423
1424 // No match found so we have to append this entry and any unique
1425 // referenced entries to *merge_cp_p.
1426 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1427 CHECK_0);
1428 }
1429 }
1430
1431 log_debug(redefine, class, constantpool)
1432 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1433 *merge_cp_length_p, scratch_i, _index_map_count);
1434
1435 if (scratch_i < scratch_cp->length()) {
1436 // Pass 1b:
1437 // old_cp is smaller than scratch_cp so there are entries in
1438 // scratch_cp that we have not yet processed. We take care of
1439 // those now.
1440 int increment = 1;
1441 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1442 switch (scratch_cp->tag_at(scratch_i).value()) {
1443 case JVM_CONSTANT_Double:
1444 case JVM_CONSTANT_Long:
1445 // double and long take two constant pool entries
1446 increment = 2;
1447 break;
1448
1449 default:
1450 increment = 1;
1451 break;
1452 }
1453
1454 int found_i =
1455 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1456 if (found_i != 0) {
1457 // Found a matching entry somewhere else in *merge_cp_p so
1458 // just need a mapping entry.
1459 map_index(scratch_cp, scratch_i, found_i);
1460 continue;
1461 }
1462
1463 // No match found so we have to append this entry and any unique
1464 // referenced entries to *merge_cp_p.
1465 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1466 CHECK_0);
1467 }
1468
1469 log_debug(redefine, class, constantpool)
1470 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1471 *merge_cp_length_p, scratch_i, _index_map_count);
1472 }
1473 finalize_operands_merge(*merge_cp_p, THREAD);
1474
1475 return true;
1476 } // end merge_constant_pools()
1477
1478
1479 // Scoped object to clean up the constant pool(s) created for merging
1480 class MergeCPCleaner {
1481 ClassLoaderData* _loader_data;
1482 ConstantPool* _cp;
1483 ConstantPool* _scratch_cp;
1484 public:
1485 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1486 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1487 ~MergeCPCleaner() {
1488 _loader_data->add_to_deallocate_list(_cp);
1489 if (_scratch_cp != NULL) {
1490 _loader_data->add_to_deallocate_list(_scratch_cp);
1491 }
1492 }
1493 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1494 };
1495
1496 // Merge constant pools between the_class and scratch_class and
1497 // potentially rewrite bytecodes in scratch_class to use the merged
1498 // constant pool.
1499 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1500 InstanceKlass* the_class, InstanceKlass* scratch_class,
1501 TRAPS) {
1502 // worst case merged constant pool length is old and new combined
1503 int merge_cp_length = the_class->constants()->length()
1504 + scratch_class->constants()->length();
1505
1506 // Constant pools are not easily reused so we allocate a new one
1507 // each time.
1508 // merge_cp is created unsafe for concurrent GC processing. It
1509 // should be marked safe before discarding it. Even though
1510 // garbage, if it crosses a card boundary, it may be scanned
1511 // in order to find the start of the first complete object on the card.
1512 ClassLoaderData* loader_data = the_class->class_loader_data();
1513 ConstantPool* merge_cp_oop =
1514 ConstantPool::allocate(loader_data,
1515 merge_cp_length,
1516 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1517 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1518
1519 HandleMark hm(THREAD); // make sure handles are cleared before
1520 // MergeCPCleaner clears out merge_cp_oop
1521 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1522
1523 // Get constants() from the old class because it could have been rewritten
1524 // while we were at a safepoint allocating a new constant pool.
1525 constantPoolHandle old_cp(THREAD, the_class->constants());
1526 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1527
1528 // If the length changed, the class was redefined out from under us. Return
1529 // an error.
1530 if (merge_cp_length != the_class->constants()->length()
1531 + scratch_class->constants()->length()) {
1532 return JVMTI_ERROR_INTERNAL;
1533 }
1534
1535 // Update the version number of the constant pools (may keep scratch_cp)
1536 merge_cp->increment_and_save_version(old_cp->version());
1537 scratch_cp->increment_and_save_version(old_cp->version());
1538
1539 ResourceMark rm(THREAD);
1540 _index_map_count = 0;
1541 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1542
1543 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1544 _operands_index_map_count = 0;
1545 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1546 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1547
1548 // reference to the cp holder is needed for copy_operands()
1549 merge_cp->set_pool_holder(scratch_class);
1550 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1551 &merge_cp_length, THREAD);
1552 merge_cp->set_pool_holder(NULL);
1553
1554 if (!result) {
1555 // The merge can fail due to memory allocation failure or due
1556 // to robustness checks.
1557 return JVMTI_ERROR_INTERNAL;
1558 }
1559
1560 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1561
1562 if (_index_map_count == 0) {
1563 // there is nothing to map between the new and merged constant pools
1564
1565 if (old_cp->length() == scratch_cp->length()) {
1566 // The old and new constant pools are the same length and the
1567 // index map is empty. This means that the three constant pools
1568 // are equivalent (but not the same). Unfortunately, the new
1569 // constant pool has not gone through link resolution nor have
1570 // the new class bytecodes gone through constant pool cache
1571 // rewriting so we can't use the old constant pool with the new
1572 // class.
1573
1574 // toss the merged constant pool at return
1575 } else if (old_cp->length() < scratch_cp->length()) {
1576 // The old constant pool has fewer entries than the new constant
1577 // pool and the index map is empty. This means the new constant
1578 // pool is a superset of the old constant pool. However, the old
1579 // class bytecodes have already gone through constant pool cache
1580 // rewriting so we can't use the new constant pool with the old
1581 // class.
1582
1583 // toss the merged constant pool at return
1584 } else {
1585 // The old constant pool has more entries than the new constant
1586 // pool and the index map is empty. This means that both the old
1587 // and merged constant pools are supersets of the new constant
1588 // pool.
1589
1590 // Replace the new constant pool with a shrunken copy of the
1591 // merged constant pool
1592 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1593 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1594 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1595 // It can't be cleaned up while there are handles to it.
1596 cp_cleaner.add_scratch_cp(scratch_cp());
1597 }
1598 } else {
1599 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1600 // don't want to loop unless we are tracing
1601 int count = 0;
1602 for (int i = 1; i < _index_map_p->length(); i++) {
1603 int value = _index_map_p->at(i);
1604
1605 if (value != -1) {
1606 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1607 count++;
1608 }
1609 }
1610 }
1611
1612 // We have entries mapped between the new and merged constant pools
1613 // so we have to rewrite some constant pool references.
1614 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1615 return JVMTI_ERROR_INTERNAL;
1616 }
1617
1618 // Replace the new constant pool with a shrunken copy of the
1619 // merged constant pool so now the rewritten bytecodes have
1620 // valid references; the previous new constant pool will get
1621 // GCed.
1622 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1623 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1624 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1625 // It can't be cleaned up while there are handles to it.
1626 cp_cleaner.add_scratch_cp(scratch_cp());
1627 }
1628
1629 return JVMTI_ERROR_NONE;
1630 } // end merge_cp_and_rewrite()
1631
1632
1633 // Rewrite constant pool references in klass scratch_class.
1634 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1635 TRAPS) {
1636
1637 // rewrite constant pool references in the methods:
1638 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1639 // propagate failure back to caller
1640 return false;
1641 }
1642
1643 // rewrite constant pool references in the class_annotations:
1644 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1645 // propagate failure back to caller
1646 return false;
1647 }
1648
1649 // rewrite constant pool references in the fields_annotations:
1650 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1651 // propagate failure back to caller
1652 return false;
1653 }
1654
1655 // rewrite constant pool references in the methods_annotations:
1656 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1657 // propagate failure back to caller
1658 return false;
1659 }
1660
1661 // rewrite constant pool references in the methods_parameter_annotations:
1662 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1663 THREAD)) {
1664 // propagate failure back to caller
1665 return false;
1666 }
1667
1668 // rewrite constant pool references in the methods_default_annotations:
1669 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1670 THREAD)) {
1671 // propagate failure back to caller
1672 return false;
1673 }
1674
1675 // rewrite constant pool references in the class_type_annotations:
1676 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1677 // propagate failure back to caller
1678 return false;
1679 }
1680
1681 // rewrite constant pool references in the fields_type_annotations:
1682 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1683 // propagate failure back to caller
1684 return false;
1685 }
1686
1687 // rewrite constant pool references in the methods_type_annotations:
1688 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1689 // propagate failure back to caller
1690 return false;
1691 }
1692
1693 // There can be type annotations in the Code part of a method_info attribute.
1694 // These annotations are not accessible, even by reflection.
1695 // Currently they are not even parsed by the ClassFileParser.
1696 // If runtime access is added they will also need to be rewritten.
1697
1698 // rewrite source file name index:
1699 u2 source_file_name_idx = scratch_class->source_file_name_index();
1700 if (source_file_name_idx != 0) {
1701 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1702 if (new_source_file_name_idx != 0) {
1703 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1704 }
1705 }
1706
1707 // rewrite class generic signature index:
1708 u2 generic_signature_index = scratch_class->generic_signature_index();
1709 if (generic_signature_index != 0) {
1710 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1711 if (new_generic_signature_index != 0) {
1712 scratch_class->set_generic_signature_index(new_generic_signature_index);
1713 }
1714 }
1715
1716 return true;
1717 } // end rewrite_cp_refs()
1718
1719 // Rewrite constant pool references in the methods.
1720 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1721 InstanceKlass* scratch_class, TRAPS) {
1722
1723 Array<Method*>* methods = scratch_class->methods();
1724
1725 if (methods == NULL || methods->length() == 0) {
1726 // no methods so nothing to do
1727 return true;
1728 }
1729
1730 // rewrite constant pool references in the methods:
1731 for (int i = methods->length() - 1; i >= 0; i--) {
1732 methodHandle method(THREAD, methods->at(i));
1733 methodHandle new_method;
1734 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1735 if (!new_method.is_null()) {
1736 // the method has been replaced so save the new method version
1737 // even in the case of an exception. original method is on the
1738 // deallocation list.
1739 methods->at_put(i, new_method());
1740 }
1741 if (HAS_PENDING_EXCEPTION) {
1742 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1743 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1744 // Need to clear pending exception here as the super caller sets
1745 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1746 CLEAR_PENDING_EXCEPTION;
1747 return false;
1748 }
1749 }
1750
1751 return true;
1752 }
1753
1754
1755 // Rewrite constant pool references in the specific method. This code
1756 // was adapted from Rewriter::rewrite_method().
1757 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1758 methodHandle *new_method_p, TRAPS) {
1759
1760 *new_method_p = methodHandle(); // default is no new method
1761
1762 // We cache a pointer to the bytecodes here in code_base. If GC
1763 // moves the Method*, then the bytecodes will also move which
1764 // will likely cause a crash. We create a NoSafepointVerifier
1765 // object to detect whether we pass a possible safepoint in this
1766 // code block.
1767 NoSafepointVerifier nsv;
1768
1769 // Bytecodes and their length
1770 address code_base = method->code_base();
1771 int code_length = method->code_size();
1772
1773 int bc_length;
1774 for (int bci = 0; bci < code_length; bci += bc_length) {
1775 address bcp = code_base + bci;
1776 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1777
1778 bc_length = Bytecodes::length_for(c);
1779 if (bc_length == 0) {
1780 // More complicated bytecodes report a length of zero so
1781 // we have to try again a slightly different way.
1782 bc_length = Bytecodes::length_at(method(), bcp);
1783 }
1784
1785 assert(bc_length != 0, "impossible bytecode length");
1786
1787 switch (c) {
1788 case Bytecodes::_ldc:
1789 {
1790 int cp_index = *(bcp + 1);
1791 int new_index = find_new_index(cp_index);
1792
1793 if (StressLdcRewrite && new_index == 0) {
1794 // If we are stressing ldc -> ldc_w rewriting, then we
1795 // always need a new_index value.
1796 new_index = cp_index;
1797 }
1798 if (new_index != 0) {
1799 // the original index is mapped so we have more work to do
1800 if (!StressLdcRewrite && new_index <= max_jubyte) {
1801 // The new value can still use ldc instead of ldc_w
1802 // unless we are trying to stress ldc -> ldc_w rewriting
1803 log_trace(redefine, class, constantpool)
1804 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1805 *(bcp + 1) = new_index;
1806 } else {
1807 log_trace(redefine, class, constantpool)
1808 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1809 // the new value needs ldc_w instead of ldc
1810 u_char inst_buffer[4]; // max instruction size is 4 bytes
1811 bcp = (address)inst_buffer;
1812 // construct new instruction sequence
1813 *bcp = Bytecodes::_ldc_w;
1814 bcp++;
1815 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1816 // See comment below for difference between put_Java_u2()
1817 // and put_native_u2().
1818 Bytes::put_Java_u2(bcp, new_index);
1819
1820 Relocator rc(method, NULL /* no RelocatorListener needed */);
1821 methodHandle m;
1822 {
1823 PauseNoSafepointVerifier pnsv(&nsv);
1824
1825 // ldc is 2 bytes and ldc_w is 3 bytes
1826 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1827 }
1828
1829 // return the new method so that the caller can update
1830 // the containing class
1831 *new_method_p = method = m;
1832 // switch our bytecode processing loop from the old method
1833 // to the new method
1834 code_base = method->code_base();
1835 code_length = method->code_size();
1836 bcp = code_base + bci;
1837 c = (Bytecodes::Code)(*bcp);
1838 bc_length = Bytecodes::length_for(c);
1839 assert(bc_length != 0, "sanity check");
1840 } // end we need ldc_w instead of ldc
1841 } // end if there is a mapped index
1842 } break;
1843
1844 // these bytecodes have a two-byte constant pool index
1845 case Bytecodes::_anewarray : // fall through
1846 case Bytecodes::_checkcast : // fall through
1847 case Bytecodes::_getfield : // fall through
1848 case Bytecodes::_getstatic : // fall through
1849 case Bytecodes::_instanceof : // fall through
1850 case Bytecodes::_invokedynamic : // fall through
1851 case Bytecodes::_invokeinterface: // fall through
1852 case Bytecodes::_invokespecial : // fall through
1853 case Bytecodes::_invokestatic : // fall through
1854 case Bytecodes::_invokevirtual : // fall through
1855 case Bytecodes::_ldc_w : // fall through
1856 case Bytecodes::_ldc2_w : // fall through
1857 case Bytecodes::_multianewarray : // fall through
1858 case Bytecodes::_new : // fall through
1859 case Bytecodes::_putfield : // fall through
1860 case Bytecodes::_putstatic :
1861 {
1862 address p = bcp + 1;
1863 int cp_index = Bytes::get_Java_u2(p);
1864 int new_index = find_new_index(cp_index);
1865 if (new_index != 0) {
1866 // the original index is mapped so update w/ new value
1867 log_trace(redefine, class, constantpool)
1868 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1869 // Rewriter::rewrite_method() uses put_native_u2() in this
1870 // situation because it is reusing the constant pool index
1871 // location for a native index into the ConstantPoolCache.
1872 // Since we are updating the constant pool index prior to
1873 // verification and ConstantPoolCache initialization, we
1874 // need to keep the new index in Java byte order.
1875 Bytes::put_Java_u2(p, new_index);
1876 }
1877 } break;
1878 default:
1879 break;
1880 }
1881 } // end for each bytecode
1882
1883 // We also need to rewrite the parameter name indexes, if there is
1884 // method parameter data present
1885 if(method->has_method_parameters()) {
1886 const int len = method->method_parameters_length();
1887 MethodParametersElement* elem = method->method_parameters_start();
1888
1889 for (int i = 0; i < len; i++) {
1890 const u2 cp_index = elem[i].name_cp_index;
1891 const u2 new_cp_index = find_new_index(cp_index);
1892 if (new_cp_index != 0) {
1893 elem[i].name_cp_index = new_cp_index;
1894 }
1895 }
1896 }
1897 } // end rewrite_cp_refs_in_method()
1898
1899
1900 // Rewrite constant pool references in the class_annotations field.
1901 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1902 InstanceKlass* scratch_class, TRAPS) {
1903
1904 AnnotationArray* class_annotations = scratch_class->class_annotations();
1905 if (class_annotations == NULL || class_annotations->length() == 0) {
1906 // no class_annotations so nothing to do
1907 return true;
1908 }
1909
1910 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1911
1912 int byte_i = 0; // byte index into class_annotations
1913 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1914 THREAD);
1915 }
1916
1917
1918 // Rewrite constant pool references in an annotations typeArray. This
1919 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1920 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1921 //
1922 // annotations_typeArray {
1923 // u2 num_annotations;
1924 // annotation annotations[num_annotations];
1925 // }
1926 //
1927 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1928 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1929
1930 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1931 // not enough room for num_annotations field
1932 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1933 return false;
1934 }
1935
1936 u2 num_annotations = Bytes::get_Java_u2((address)
1937 annotations_typeArray->adr_at(byte_i_ref));
1938 byte_i_ref += 2;
1939
1940 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1941
1942 int calc_num_annotations = 0;
1943 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1944 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1945 byte_i_ref, THREAD)) {
1946 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1947 // propagate failure back to caller
1948 return false;
1949 }
1950 }
1951 assert(num_annotations == calc_num_annotations, "sanity check");
1952
1953 return true;
1954 } // end rewrite_cp_refs_in_annotations_typeArray()
1955
1956
1957 // Rewrite constant pool references in the annotation struct portion of
1958 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1959 // the 2nd-edition of the VM spec:
1960 //
1961 // struct annotation {
1962 // u2 type_index;
1963 // u2 num_element_value_pairs;
1964 // {
1965 // u2 element_name_index;
1966 // element_value value;
1967 // } element_value_pairs[num_element_value_pairs];
1968 // }
1969 //
1970 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1971 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1972 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1973 // not enough room for smallest annotation_struct
1974 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1975 return false;
1976 }
1977
1978 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1979 byte_i_ref, "type_index", THREAD);
1980
1981 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1982 annotations_typeArray->adr_at(byte_i_ref));
1983 byte_i_ref += 2;
1984
1985 log_debug(redefine, class, annotation)
1986 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1987
1988 int calc_num_element_value_pairs = 0;
1989 for (; calc_num_element_value_pairs < num_element_value_pairs;
1990 calc_num_element_value_pairs++) {
1991 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1992 // not enough room for another element_name_index, let alone
1993 // the rest of another component
1994 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1995 return false;
1996 }
1997
1998 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1999 annotations_typeArray, byte_i_ref,
2000 "element_name_index", THREAD);
2001
2002 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2003
2004 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
2005 byte_i_ref, THREAD)) {
2006 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2007 // propagate failure back to caller
2008 return false;
2009 }
2010 } // end for each component
2011 assert(num_element_value_pairs == calc_num_element_value_pairs,
2012 "sanity check");
2013
2014 return true;
2015 } // end rewrite_cp_refs_in_annotation_struct()
2016
2017
2018 // Rewrite a constant pool reference at the current position in
2019 // annotations_typeArray if needed. Returns the original constant
2020 // pool reference if a rewrite was not needed or the new constant
2021 // pool reference if a rewrite was needed.
2022 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2023 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2024 const char * trace_mesg, TRAPS) {
2025
2026 address cp_index_addr = (address)
2027 annotations_typeArray->adr_at(byte_i_ref);
2028 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2029 u2 new_cp_index = find_new_index(old_cp_index);
2030 if (new_cp_index != 0) {
2031 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2032 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2033 old_cp_index = new_cp_index;
2034 }
2035 byte_i_ref += 2;
2036 return old_cp_index;
2037 }
2038
2039
2040 // Rewrite constant pool references in the element_value portion of an
2041 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2042 // the 2nd-edition of the VM spec:
2043 //
2044 // struct element_value {
2045 // u1 tag;
2046 // union {
2047 // u2 const_value_index;
2048 // {
2049 // u2 type_name_index;
2050 // u2 const_name_index;
2051 // } enum_const_value;
2052 // u2 class_info_index;
2053 // annotation annotation_value;
2054 // struct {
2055 // u2 num_values;
2056 // element_value values[num_values];
2057 // } array_value;
2058 // } value;
2059 // }
2060 //
2061 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2062 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2063
2064 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2065 // not enough room for a tag let alone the rest of an element_value
2066 log_debug(redefine, class, annotation)("length() is too small for a tag");
2067 return false;
2068 }
2069
2070 u1 tag = annotations_typeArray->at(byte_i_ref);
2071 byte_i_ref++;
2072 log_debug(redefine, class, annotation)("tag='%c'", tag);
2073
2074 switch (tag) {
2075 // These BaseType tag values are from Table 4.2 in VM spec:
2076 case 'B': // byte
2077 case 'C': // char
2078 case 'D': // double
2079 case 'F': // float
2080 case 'I': // int
2081 case 'J': // long
2082 case 'S': // short
2083 case 'Z': // boolean
2084
2085 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2086 // the VM spec:
2087 case 's':
2088 {
2089 // For the above tag values (including the BaseType values),
2090 // value.const_value_index is right union field.
2091
2092 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2093 // not enough room for a const_value_index
2094 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2095 return false;
2096 }
2097
2098 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2099 annotations_typeArray, byte_i_ref,
2100 "const_value_index", THREAD);
2101
2102 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2103 } break;
2104
2105 case 'e':
2106 {
2107 // for the above tag value, value.enum_const_value is right union field
2108
2109 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2110 // not enough room for a enum_const_value
2111 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2112 return false;
2113 }
2114
2115 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2116 annotations_typeArray, byte_i_ref,
2117 "type_name_index", THREAD);
2118
2119 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2120 annotations_typeArray, byte_i_ref,
2121 "const_name_index", THREAD);
2122
2123 log_debug(redefine, class, annotation)
2124 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2125 } break;
2126
2127 case 'c':
2128 {
2129 // for the above tag value, value.class_info_index is right union field
2130
2131 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2132 // not enough room for a class_info_index
2133 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2134 return false;
2135 }
2136
2137 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2138 annotations_typeArray, byte_i_ref,
2139 "class_info_index", THREAD);
2140
2141 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2142 } break;
2143
2144 case '@':
2145 // For the above tag value, value.attr_value is the right union
2146 // field. This is a nested annotation.
2147 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2148 byte_i_ref, THREAD)) {
2149 // propagate failure back to caller
2150 return false;
2151 }
2152 break;
2153
2154 case '[':
2155 {
2156 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2157 // not enough room for a num_values field
2158 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2159 return false;
2160 }
2161
2162 // For the above tag value, value.array_value is the right union
2163 // field. This is an array of nested element_value.
2164 u2 num_values = Bytes::get_Java_u2((address)
2165 annotations_typeArray->adr_at(byte_i_ref));
2166 byte_i_ref += 2;
2167 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2168
2169 int calc_num_values = 0;
2170 for (; calc_num_values < num_values; calc_num_values++) {
2171 if (!rewrite_cp_refs_in_element_value(
2172 annotations_typeArray, byte_i_ref, THREAD)) {
2173 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2174 // propagate failure back to caller
2175 return false;
2176 }
2177 }
2178 assert(num_values == calc_num_values, "sanity check");
2179 } break;
2180
2181 default:
2182 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2183 return false;
2184 } // end decode tag field
2185
2186 return true;
2187 } // end rewrite_cp_refs_in_element_value()
2188
2189
2190 // Rewrite constant pool references in a fields_annotations field.
2191 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2192 InstanceKlass* scratch_class, TRAPS) {
2193
2194 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2195
2196 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2197 // no fields_annotations so nothing to do
2198 return true;
2199 }
2200
2201 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2202
2203 for (int i = 0; i < fields_annotations->length(); i++) {
2204 AnnotationArray* field_annotations = fields_annotations->at(i);
2205 if (field_annotations == NULL || field_annotations->length() == 0) {
2206 // this field does not have any annotations so skip it
2207 continue;
2208 }
2209
2210 int byte_i = 0; // byte index into field_annotations
2211 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2212 THREAD)) {
2213 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2214 // propagate failure back to caller
2215 return false;
2216 }
2217 }
2218
2219 return true;
2220 } // end rewrite_cp_refs_in_fields_annotations()
2221
2222
2223 // Rewrite constant pool references in a methods_annotations field.
2224 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2225 InstanceKlass* scratch_class, TRAPS) {
2226
2227 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2228 Method* m = scratch_class->methods()->at(i);
2229 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2230
2231 if (method_annotations == NULL || method_annotations->length() == 0) {
2232 // this method does not have any annotations so skip it
2233 continue;
2234 }
2235
2236 int byte_i = 0; // byte index into method_annotations
2237 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2238 THREAD)) {
2239 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2240 // propagate failure back to caller
2241 return false;
2242 }
2243 }
2244
2245 return true;
2246 } // end rewrite_cp_refs_in_methods_annotations()
2247
2248
2249 // Rewrite constant pool references in a methods_parameter_annotations
2250 // field. This "structure" is adapted from the
2251 // RuntimeVisibleParameterAnnotations_attribute described in section
2252 // 4.8.17 of the 2nd-edition of the VM spec:
2253 //
2254 // methods_parameter_annotations_typeArray {
2255 // u1 num_parameters;
2256 // {
2257 // u2 num_annotations;
2258 // annotation annotations[num_annotations];
2259 // } parameter_annotations[num_parameters];
2260 // }
2261 //
2262 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2263 InstanceKlass* scratch_class, TRAPS) {
2264
2265 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2266 Method* m = scratch_class->methods()->at(i);
2267 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2268 if (method_parameter_annotations == NULL
2269 || method_parameter_annotations->length() == 0) {
2270 // this method does not have any parameter annotations so skip it
2271 continue;
2272 }
2273
2274 if (method_parameter_annotations->length() < 1) {
2275 // not enough room for a num_parameters field
2276 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2277 return false;
2278 }
2279
2280 int byte_i = 0; // byte index into method_parameter_annotations
2281
2282 u1 num_parameters = method_parameter_annotations->at(byte_i);
2283 byte_i++;
2284
2285 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2286
2287 int calc_num_parameters = 0;
2288 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2289 if (!rewrite_cp_refs_in_annotations_typeArray(
2290 method_parameter_annotations, byte_i, THREAD)) {
2291 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2292 // propagate failure back to caller
2293 return false;
2294 }
2295 }
2296 assert(num_parameters == calc_num_parameters, "sanity check");
2297 }
2298
2299 return true;
2300 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2301
2302
2303 // Rewrite constant pool references in a methods_default_annotations
2304 // field. This "structure" is adapted from the AnnotationDefault_attribute
2305 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2306 //
2307 // methods_default_annotations_typeArray {
2308 // element_value default_value;
2309 // }
2310 //
2311 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2312 InstanceKlass* scratch_class, TRAPS) {
2313
2314 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2315 Method* m = scratch_class->methods()->at(i);
2316 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2317 if (method_default_annotations == NULL
2318 || method_default_annotations->length() == 0) {
2319 // this method does not have any default annotations so skip it
2320 continue;
2321 }
2322
2323 int byte_i = 0; // byte index into method_default_annotations
2324
2325 if (!rewrite_cp_refs_in_element_value(
2326 method_default_annotations, byte_i, THREAD)) {
2327 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2328 // propagate failure back to caller
2329 return false;
2330 }
2331 }
2332
2333 return true;
2334 } // end rewrite_cp_refs_in_methods_default_annotations()
2335
2336
2337 // Rewrite constant pool references in a class_type_annotations field.
2338 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2339 InstanceKlass* scratch_class, TRAPS) {
2340
2341 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2342 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2343 // no class_type_annotations so nothing to do
2344 return true;
2345 }
2346
2347 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2348
2349 int byte_i = 0; // byte index into class_type_annotations
2350 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2351 byte_i, "ClassFile", THREAD);
2352 } // end rewrite_cp_refs_in_class_type_annotations()
2353
2354
2355 // Rewrite constant pool references in a fields_type_annotations field.
2356 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2357 InstanceKlass* scratch_class, TRAPS) {
2358
2359 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2360 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2361 // no fields_type_annotations so nothing to do
2362 return true;
2363 }
2364
2365 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2366
2367 for (int i = 0; i < fields_type_annotations->length(); i++) {
2368 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2369 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2370 // this field does not have any annotations so skip it
2371 continue;
2372 }
2373
2374 int byte_i = 0; // byte index into field_type_annotations
2375 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2376 byte_i, "field_info", THREAD)) {
2377 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2378 // propagate failure back to caller
2379 return false;
2380 }
2381 }
2382
2383 return true;
2384 } // end rewrite_cp_refs_in_fields_type_annotations()
2385
2386
2387 // Rewrite constant pool references in a methods_type_annotations field.
2388 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2389 InstanceKlass* scratch_class, TRAPS) {
2390
2391 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2392 Method* m = scratch_class->methods()->at(i);
2393 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2394
2395 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2396 // this method does not have any annotations so skip it
2397 continue;
2398 }
2399
2400 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2401
2402 int byte_i = 0; // byte index into method_type_annotations
2403 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2404 byte_i, "method_info", THREAD)) {
2405 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2406 // propagate failure back to caller
2407 return false;
2408 }
2409 }
2410
2411 return true;
2412 } // end rewrite_cp_refs_in_methods_type_annotations()
2413
2414
2415 // Rewrite constant pool references in a type_annotations
2416 // field. This "structure" is adapted from the
2417 // RuntimeVisibleTypeAnnotations_attribute described in
2418 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2419 //
2420 // type_annotations_typeArray {
2421 // u2 num_annotations;
2422 // type_annotation annotations[num_annotations];
2423 // }
2424 //
2425 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2426 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2427 const char * location_mesg, TRAPS) {
2428
2429 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2430 // not enough room for num_annotations field
2431 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2432 return false;
2433 }
2434
2435 u2 num_annotations = Bytes::get_Java_u2((address)
2436 type_annotations_typeArray->adr_at(byte_i_ref));
2437 byte_i_ref += 2;
2438
2439 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2440
2441 int calc_num_annotations = 0;
2442 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2443 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2444 byte_i_ref, location_mesg, THREAD)) {
2445 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2446 // propagate failure back to caller
2447 return false;
2448 }
2449 }
2450 assert(num_annotations == calc_num_annotations, "sanity check");
2451
2452 if (byte_i_ref != type_annotations_typeArray->length()) {
2453 log_debug(redefine, class, annotation)
2454 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2455 byte_i_ref, type_annotations_typeArray->length());
2456 return false;
2457 }
2458
2459 return true;
2460 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2461
2462
2463 // Rewrite constant pool references in a type_annotation
2464 // field. This "structure" is adapted from the
2465 // RuntimeVisibleTypeAnnotations_attribute described in
2466 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2467 //
2468 // type_annotation {
2469 // u1 target_type;
2470 // union {
2471 // type_parameter_target;
2472 // supertype_target;
2473 // type_parameter_bound_target;
2474 // empty_target;
2475 // method_formal_parameter_target;
2476 // throws_target;
2477 // localvar_target;
2478 // catch_target;
2479 // offset_target;
2480 // type_argument_target;
2481 // } target_info;
2482 // type_path target_path;
2483 // annotation anno;
2484 // }
2485 //
2486 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2487 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2488 const char * location_mesg, TRAPS) {
2489
2490 if (!skip_type_annotation_target(type_annotations_typeArray,
2491 byte_i_ref, location_mesg, THREAD)) {
2492 return false;
2493 }
2494
2495 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2496 byte_i_ref, THREAD)) {
2497 return false;
2498 }
2499
2500 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2501 byte_i_ref, THREAD)) {
2502 return false;
2503 }
2504
2505 return true;
2506 } // end rewrite_cp_refs_in_type_annotation_struct()
2507
2508
2509 // Read, verify and skip over the target_type and target_info part
2510 // so that rewriting can continue in the later parts of the struct.
2511 //
2512 // u1 target_type;
2513 // union {
2514 // type_parameter_target;
2515 // supertype_target;
2516 // type_parameter_bound_target;
2517 // empty_target;
2518 // method_formal_parameter_target;
2519 // throws_target;
2520 // localvar_target;
2521 // catch_target;
2522 // offset_target;
2523 // type_argument_target;
2524 // } target_info;
2525 //
2526 bool VM_RedefineClasses::skip_type_annotation_target(
2527 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2528 const char * location_mesg, TRAPS) {
2529
2530 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2531 // not enough room for a target_type let alone the rest of a type_annotation
2532 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2533 return false;
2534 }
2535
2536 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2537 byte_i_ref += 1;
2538 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2539 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2540
2541 // Skip over target_info
2542 switch (target_type) {
2543 case 0x00:
2544 // kind: type parameter declaration of generic class or interface
2545 // location: ClassFile
2546 case 0x01:
2547 // kind: type parameter declaration of generic method or constructor
2548 // location: method_info
2549
2550 {
2551 // struct:
2552 // type_parameter_target {
2553 // u1 type_parameter_index;
2554 // }
2555 //
2556 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2557 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2558 return false;
2559 }
2560
2561 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2562 byte_i_ref += 1;
2563
2564 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2565 } break;
2566
2567 case 0x10:
2568 // kind: type in extends clause of class or interface declaration
2569 // (including the direct superclass of an anonymous class declaration),
2570 // or in implements clause of interface declaration
2571 // location: ClassFile
2572
2573 {
2574 // struct:
2575 // supertype_target {
2576 // u2 supertype_index;
2577 // }
2578 //
2579 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2580 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2581 return false;
2582 }
2583
2584 u2 supertype_index = Bytes::get_Java_u2((address)
2585 type_annotations_typeArray->adr_at(byte_i_ref));
2586 byte_i_ref += 2;
2587
2588 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2589 } break;
2590
2591 case 0x11:
2592 // kind: type in bound of type parameter declaration of generic class or interface
2593 // location: ClassFile
2594 case 0x12:
2595 // kind: type in bound of type parameter declaration of generic method or constructor
2596 // location: method_info
2597
2598 {
2599 // struct:
2600 // type_parameter_bound_target {
2601 // u1 type_parameter_index;
2602 // u1 bound_index;
2603 // }
2604 //
2605 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2606 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2607 return false;
2608 }
2609
2610 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2611 byte_i_ref += 1;
2612 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2613 byte_i_ref += 1;
2614
2615 log_debug(redefine, class, annotation)
2616 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2617 } break;
2618
2619 case 0x13:
2620 // kind: type in field declaration
2621 // location: field_info
2622 case 0x14:
2623 // kind: return type of method, or type of newly constructed object
2624 // location: method_info
2625 case 0x15:
2626 // kind: receiver type of method or constructor
2627 // location: method_info
2628
2629 {
2630 // struct:
2631 // empty_target {
2632 // }
2633 //
2634 log_debug(redefine, class, annotation)("empty_target");
2635 } break;
2636
2637 case 0x16:
2638 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2639 // location: method_info
2640
2641 {
2642 // struct:
2643 // formal_parameter_target {
2644 // u1 formal_parameter_index;
2645 // }
2646 //
2647 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2648 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2649 return false;
2650 }
2651
2652 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2653 byte_i_ref += 1;
2654
2655 log_debug(redefine, class, annotation)
2656 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2657 } break;
2658
2659 case 0x17:
2660 // kind: type in throws clause of method or constructor
2661 // location: method_info
2662
2663 {
2664 // struct:
2665 // throws_target {
2666 // u2 throws_type_index
2667 // }
2668 //
2669 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2670 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2671 return false;
2672 }
2673
2674 u2 throws_type_index = Bytes::get_Java_u2((address)
2675 type_annotations_typeArray->adr_at(byte_i_ref));
2676 byte_i_ref += 2;
2677
2678 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2679 } break;
2680
2681 case 0x40:
2682 // kind: type in local variable declaration
2683 // location: Code
2684 case 0x41:
2685 // kind: type in resource variable declaration
2686 // location: Code
2687
2688 {
2689 // struct:
2690 // localvar_target {
2691 // u2 table_length;
2692 // struct {
2693 // u2 start_pc;
2694 // u2 length;
2695 // u2 index;
2696 // } table[table_length];
2697 // }
2698 //
2699 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2700 // not enough room for a table_length let alone the rest of a localvar_target
2701 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2702 return false;
2703 }
2704
2705 u2 table_length = Bytes::get_Java_u2((address)
2706 type_annotations_typeArray->adr_at(byte_i_ref));
2707 byte_i_ref += 2;
2708
2709 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2710
2711 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2712 int table_size = table_length * table_struct_size;
2713
2714 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2715 // not enough room for a table
2716 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2717 return false;
2718 }
2719
2720 // Skip over table
2721 byte_i_ref += table_size;
2722 } break;
2723
2724 case 0x42:
2725 // kind: type in exception parameter declaration
2726 // location: Code
2727
2728 {
2729 // struct:
2730 // catch_target {
2731 // u2 exception_table_index;
2732 // }
2733 //
2734 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2735 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2736 return false;
2737 }
2738
2739 u2 exception_table_index = Bytes::get_Java_u2((address)
2740 type_annotations_typeArray->adr_at(byte_i_ref));
2741 byte_i_ref += 2;
2742
2743 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2744 } break;
2745
2746 case 0x43:
2747 // kind: type in instanceof expression
2748 // location: Code
2749 case 0x44:
2750 // kind: type in new expression
2751 // location: Code
2752 case 0x45:
2753 // kind: type in method reference expression using ::new
2754 // location: Code
2755 case 0x46:
2756 // kind: type in method reference expression using ::Identifier
2757 // location: Code
2758
2759 {
2760 // struct:
2761 // offset_target {
2762 // u2 offset;
2763 // }
2764 //
2765 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2766 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2767 return false;
2768 }
2769
2770 u2 offset = Bytes::get_Java_u2((address)
2771 type_annotations_typeArray->adr_at(byte_i_ref));
2772 byte_i_ref += 2;
2773
2774 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2775 } break;
2776
2777 case 0x47:
2778 // kind: type in cast expression
2779 // location: Code
2780 case 0x48:
2781 // kind: type argument for generic constructor in new expression or
2782 // explicit constructor invocation statement
2783 // location: Code
2784 case 0x49:
2785 // kind: type argument for generic method in method invocation expression
2786 // location: Code
2787 case 0x4A:
2788 // kind: type argument for generic constructor in method reference expression using ::new
2789 // location: Code
2790 case 0x4B:
2791 // kind: type argument for generic method in method reference expression using ::Identifier
2792 // location: Code
2793
2794 {
2795 // struct:
2796 // type_argument_target {
2797 // u2 offset;
2798 // u1 type_argument_index;
2799 // }
2800 //
2801 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2802 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2803 return false;
2804 }
2805
2806 u2 offset = Bytes::get_Java_u2((address)
2807 type_annotations_typeArray->adr_at(byte_i_ref));
2808 byte_i_ref += 2;
2809 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2810 byte_i_ref += 1;
2811
2812 log_debug(redefine, class, annotation)
2813 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2814 } break;
2815
2816 default:
2817 log_debug(redefine, class, annotation)("unknown target_type");
2818 #ifdef ASSERT
2819 ShouldNotReachHere();
2820 #endif
2821 return false;
2822 }
2823
2824 return true;
2825 } // end skip_type_annotation_target()
2826
2827
2828 // Read, verify and skip over the type_path part so that rewriting
2829 // can continue in the later parts of the struct.
2830 //
2831 // type_path {
2832 // u1 path_length;
2833 // {
2834 // u1 type_path_kind;
2835 // u1 type_argument_index;
2836 // } path[path_length];
2837 // }
2838 //
2839 bool VM_RedefineClasses::skip_type_annotation_type_path(
2840 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2841
2842 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2843 // not enough room for a path_length let alone the rest of the type_path
2844 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2845 return false;
2846 }
2847
2848 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2849 byte_i_ref += 1;
2850
2851 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2852
2853 int calc_path_length = 0;
2854 for (; calc_path_length < path_length; calc_path_length++) {
2855 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2856 // not enough room for a path
2857 log_debug(redefine, class, annotation)
2858 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2859 return false;
2860 }
2861
2862 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2863 byte_i_ref += 1;
2864 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2865 byte_i_ref += 1;
2866
2867 log_debug(redefine, class, annotation)
2868 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2869 calc_path_length, type_path_kind, type_argument_index);
2870
2871 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2872 // not enough room for a path
2873 log_debug(redefine, class, annotation)("inconsistent type_path values");
2874 return false;
2875 }
2876 }
2877 assert(path_length == calc_path_length, "sanity check");
2878
2879 return true;
2880 } // end skip_type_annotation_type_path()
2881
2882
2883 // Rewrite constant pool references in the method's stackmap table.
2884 // These "structures" are adapted from the StackMapTable_attribute that
2885 // is described in section 4.8.4 of the 6.0 version of the VM spec
2886 // (dated 2005.10.26):
2887 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2888 //
2889 // stack_map {
2890 // u2 number_of_entries;
2891 // stack_map_frame entries[number_of_entries];
2892 // }
2893 //
2894 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2895 const methodHandle& method, TRAPS) {
2896
2897 if (!method->has_stackmap_table()) {
2898 return;
2899 }
2900
2901 AnnotationArray* stackmap_data = method->stackmap_data();
2902 address stackmap_p = (address)stackmap_data->adr_at(0);
2903 address stackmap_end = stackmap_p + stackmap_data->length();
2904
2905 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2906 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2907 stackmap_p += 2;
2908
2909 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2910
2911 // walk through each stack_map_frame
2912 u2 calc_number_of_entries = 0;
2913 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2914 // The stack_map_frame structure is a u1 frame_type followed by
2915 // 0 or more bytes of data:
2916 //
2917 // union stack_map_frame {
2918 // same_frame;
2919 // same_locals_1_stack_item_frame;
2920 // same_locals_1_stack_item_frame_extended;
2921 // chop_frame;
2922 // same_frame_extended;
2923 // append_frame;
2924 // full_frame;
2925 // }
2926
2927 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2928 u1 frame_type = *stackmap_p;
2929 stackmap_p++;
2930
2931 // same_frame {
2932 // u1 frame_type = SAME; /* 0-63 */
2933 // }
2934 if (frame_type <= 63) {
2935 // nothing more to do for same_frame
2936 }
2937
2938 // same_locals_1_stack_item_frame {
2939 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2940 // verification_type_info stack[1];
2941 // }
2942 else if (frame_type >= 64 && frame_type <= 127) {
2943 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2944 calc_number_of_entries, frame_type, THREAD);
2945 }
2946
2947 // reserved for future use
2948 else if (frame_type >= 128 && frame_type <= 246) {
2949 // nothing more to do for reserved frame_types
2950 }
2951
2952 // same_locals_1_stack_item_frame_extended {
2953 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2954 // u2 offset_delta;
2955 // verification_type_info stack[1];
2956 // }
2957 else if (frame_type == 247) {
2958 stackmap_p += 2;
2959 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2960 calc_number_of_entries, frame_type, THREAD);
2961 }
2962
2963 // chop_frame {
2964 // u1 frame_type = CHOP; /* 248-250 */
2965 // u2 offset_delta;
2966 // }
2967 else if (frame_type >= 248 && frame_type <= 250) {
2968 stackmap_p += 2;
2969 }
2970
2971 // same_frame_extended {
2972 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2973 // u2 offset_delta;
2974 // }
2975 else if (frame_type == 251) {
2976 stackmap_p += 2;
2977 }
2978
2979 // append_frame {
2980 // u1 frame_type = APPEND; /* 252-254 */
2981 // u2 offset_delta;
2982 // verification_type_info locals[frame_type - 251];
2983 // }
2984 else if (frame_type >= 252 && frame_type <= 254) {
2985 assert(stackmap_p + 2 <= stackmap_end,
2986 "no room for offset_delta");
2987 stackmap_p += 2;
2988 u1 len = frame_type - 251;
2989 for (u1 i = 0; i < len; i++) {
2990 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2991 calc_number_of_entries, frame_type, THREAD);
2992 }
2993 }
2994
2995 // full_frame {
2996 // u1 frame_type = FULL_FRAME; /* 255 */
2997 // u2 offset_delta;
2998 // u2 number_of_locals;
2999 // verification_type_info locals[number_of_locals];
3000 // u2 number_of_stack_items;
3001 // verification_type_info stack[number_of_stack_items];
3002 // }
3003 else if (frame_type == 255) {
3004 assert(stackmap_p + 2 + 2 <= stackmap_end,
3005 "no room for smallest full_frame");
3006 stackmap_p += 2;
3007
3008 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3009 stackmap_p += 2;
3010
3011 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3012 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3013 calc_number_of_entries, frame_type, THREAD);
3014 }
3015
3016 // Use the largest size for the number_of_stack_items, but only get
3017 // the right number of bytes.
3018 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3019 stackmap_p += 2;
3020
3021 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3022 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3023 calc_number_of_entries, frame_type, THREAD);
3024 }
3025 }
3026 } // end while there is a stack_map_frame
3027 assert(number_of_entries == calc_number_of_entries, "sanity check");
3028 } // end rewrite_cp_refs_in_stack_map_table()
3029
3030
3031 // Rewrite constant pool references in the verification type info
3032 // portion of the method's stackmap table. These "structures" are
3033 // adapted from the StackMapTable_attribute that is described in
3034 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3035 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3036 //
3037 // The verification_type_info structure is a u1 tag followed by 0 or
3038 // more bytes of data:
3039 //
3040 // union verification_type_info {
3041 // Top_variable_info;
3042 // Integer_variable_info;
3043 // Float_variable_info;
3044 // Long_variable_info;
3045 // Double_variable_info;
3046 // Null_variable_info;
3047 // UninitializedThis_variable_info;
3048 // Object_variable_info;
3049 // Uninitialized_variable_info;
3050 // }
3051 //
3052 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3053 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3054 u1 frame_type, TRAPS) {
3055
3056 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3057 u1 tag = *stackmap_p_ref;
3058 stackmap_p_ref++;
3059
3060 switch (tag) {
3061 // Top_variable_info {
3062 // u1 tag = ITEM_Top; /* 0 */
3063 // }
3064 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3065 case 0: // fall through
3066
3067 // Integer_variable_info {
3068 // u1 tag = ITEM_Integer; /* 1 */
3069 // }
3070 case ITEM_Integer: // fall through
3071
3072 // Float_variable_info {
3073 // u1 tag = ITEM_Float; /* 2 */
3074 // }
3075 case ITEM_Float: // fall through
3076
3077 // Double_variable_info {
3078 // u1 tag = ITEM_Double; /* 3 */
3079 // }
3080 case ITEM_Double: // fall through
3081
3082 // Long_variable_info {
3083 // u1 tag = ITEM_Long; /* 4 */
3084 // }
3085 case ITEM_Long: // fall through
3086
3087 // Null_variable_info {
3088 // u1 tag = ITEM_Null; /* 5 */
3089 // }
3090 case ITEM_Null: // fall through
3091
3092 // UninitializedThis_variable_info {
3093 // u1 tag = ITEM_UninitializedThis; /* 6 */
3094 // }
3095 case ITEM_UninitializedThis:
3096 // nothing more to do for the above tag types
3097 break;
3098
3099 // Object_variable_info {
3100 // u1 tag = ITEM_Object; /* 7 */
3101 // u2 cpool_index;
3102 // }
3103 case ITEM_Object:
3104 {
3105 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3106 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3107 u2 new_cp_index = find_new_index(cpool_index);
3108 if (new_cp_index != 0) {
3109 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3110 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3111 cpool_index = new_cp_index;
3112 }
3113 stackmap_p_ref += 2;
3114
3115 log_debug(redefine, class, stackmap)
3116 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3117 } break;
3118
3119 // Uninitialized_variable_info {
3120 // u1 tag = ITEM_Uninitialized; /* 8 */
3121 // u2 offset;
3122 // }
3123 case ITEM_Uninitialized:
3124 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3125 stackmap_p_ref += 2;
3126 break;
3127
3128 default:
3129 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3130 ShouldNotReachHere();
3131 break;
3132 } // end switch (tag)
3133 } // end rewrite_cp_refs_in_verification_type_info()
3134
3135
3136 // Change the constant pool associated with klass scratch_class to
3137 // scratch_cp. If shrink is true, then scratch_cp_length elements
3138 // are copied from scratch_cp to a smaller constant pool and the
3139 // smaller constant pool is associated with scratch_class.
3140 void VM_RedefineClasses::set_new_constant_pool(
3141 ClassLoaderData* loader_data,
3142 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3143 int scratch_cp_length, TRAPS) {
3144 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3145
3146 // scratch_cp is a merged constant pool and has enough space for a
3147 // worst case merge situation. We want to associate the minimum
3148 // sized constant pool with the klass to save space.
3149 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3150 constantPoolHandle smaller_cp(THREAD, cp);
3151
3152 // preserve version() value in the smaller copy
3153 int version = scratch_cp->version();
3154 assert(version != 0, "sanity check");
3155 smaller_cp->set_version(version);
3156
3157 // attach klass to new constant pool
3158 // reference to the cp holder is needed for copy_operands()
3159 smaller_cp->set_pool_holder(scratch_class);
3160
3161 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3162 if (HAS_PENDING_EXCEPTION) {
3163 // Exception is handled in the caller
3164 loader_data->add_to_deallocate_list(smaller_cp());
3165 return;
3166 }
3167 scratch_cp = smaller_cp;
3168
3169 // attach new constant pool to klass
3170 scratch_class->set_constants(scratch_cp());
3171 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3172
3173 int i; // for portability
3174
3175 // update each field in klass to use new constant pool indices as needed
3176 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3177 jshort cur_index = fs.name_index();
3178 jshort new_index = find_new_index(cur_index);
3179 if (new_index != 0) {
3180 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3181 fs.set_name_index(new_index);
3182 }
3183 cur_index = fs.signature_index();
3184 new_index = find_new_index(cur_index);
3185 if (new_index != 0) {
3186 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3187 fs.set_signature_index(new_index);
3188 }
3189 cur_index = fs.initval_index();
3190 new_index = find_new_index(cur_index);
3191 if (new_index != 0) {
3192 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3193 fs.set_initval_index(new_index);
3194 }
3195 cur_index = fs.generic_signature_index();
3196 new_index = find_new_index(cur_index);
3197 if (new_index != 0) {
3198 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3199 fs.set_generic_signature_index(new_index);
3200 }
3201 } // end for each field
3202
3203 // Update constant pool indices in the inner classes info to use
3204 // new constant indices as needed. The inner classes info is a
3205 // quadruple:
3206 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3207 InnerClassesIterator iter(scratch_class);
3208 for (; !iter.done(); iter.next()) {
3209 int cur_index = iter.inner_class_info_index();
3210 if (cur_index == 0) {
3211 continue; // JVM spec. allows null inner class refs so skip it
3212 }
3213 int new_index = find_new_index(cur_index);
3214 if (new_index != 0) {
3215 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3216 iter.set_inner_class_info_index(new_index);
3217 }
3218 cur_index = iter.outer_class_info_index();
3219 new_index = find_new_index(cur_index);
3220 if (new_index != 0) {
3221 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3222 iter.set_outer_class_info_index(new_index);
3223 }
3224 cur_index = iter.inner_name_index();
3225 new_index = find_new_index(cur_index);
3226 if (new_index != 0) {
3227 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3228 iter.set_inner_name_index(new_index);
3229 }
3230 } // end for each inner class
3231
3232 // Attach each method in klass to the new constant pool and update
3233 // to use new constant pool indices as needed:
3234 Array<Method*>* methods = scratch_class->methods();
3235 for (i = methods->length() - 1; i >= 0; i--) {
3236 methodHandle method(THREAD, methods->at(i));
3237 method->set_constants(scratch_cp());
3238
3239 int new_index = find_new_index(method->name_index());
3240 if (new_index != 0) {
3241 log_trace(redefine, class, constantpool)
3242 ("method-name_index change: %d to %d", method->name_index(), new_index);
3243 method->set_name_index(new_index);
3244 }
3245 new_index = find_new_index(method->signature_index());
3246 if (new_index != 0) {
3247 log_trace(redefine, class, constantpool)
3248 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3249 method->set_signature_index(new_index);
3250 }
3251 new_index = find_new_index(method->generic_signature_index());
3252 if (new_index != 0) {
3253 log_trace(redefine, class, constantpool)
3254 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3255 method->set_generic_signature_index(new_index);
3256 }
3257
3258 // Update constant pool indices in the method's checked exception
3259 // table to use new constant indices as needed.
3260 int cext_length = method->checked_exceptions_length();
3261 if (cext_length > 0) {
3262 CheckedExceptionElement * cext_table =
3263 method->checked_exceptions_start();
3264 for (int j = 0; j < cext_length; j++) {
3265 int cur_index = cext_table[j].class_cp_index;
3266 int new_index = find_new_index(cur_index);
3267 if (new_index != 0) {
3268 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3269 cext_table[j].class_cp_index = (u2)new_index;
3270 }
3271 } // end for each checked exception table entry
3272 } // end if there are checked exception table entries
3273
3274 // Update each catch type index in the method's exception table
3275 // to use new constant pool indices as needed. The exception table
3276 // holds quadruple entries of the form:
3277 // (beg_bci, end_bci, handler_bci, klass_index)
3278
3279 ExceptionTable ex_table(method());
3280 int ext_length = ex_table.length();
3281
3282 for (int j = 0; j < ext_length; j ++) {
3283 int cur_index = ex_table.catch_type_index(j);
3284 int new_index = find_new_index(cur_index);
3285 if (new_index != 0) {
3286 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3287 ex_table.set_catch_type_index(j, new_index);
3288 }
3289 } // end for each exception table entry
3290
3291 // Update constant pool indices in the method's local variable
3292 // table to use new constant indices as needed. The local variable
3293 // table hold sextuple entries of the form:
3294 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3295 int lvt_length = method->localvariable_table_length();
3296 if (lvt_length > 0) {
3297 LocalVariableTableElement * lv_table =
3298 method->localvariable_table_start();
3299 for (int j = 0; j < lvt_length; j++) {
3300 int cur_index = lv_table[j].name_cp_index;
3301 int new_index = find_new_index(cur_index);
3302 if (new_index != 0) {
3303 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3304 lv_table[j].name_cp_index = (u2)new_index;
3305 }
3306 cur_index = lv_table[j].descriptor_cp_index;
3307 new_index = find_new_index(cur_index);
3308 if (new_index != 0) {
3309 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3310 lv_table[j].descriptor_cp_index = (u2)new_index;
3311 }
3312 cur_index = lv_table[j].signature_cp_index;
3313 new_index = find_new_index(cur_index);
3314 if (new_index != 0) {
3315 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3316 lv_table[j].signature_cp_index = (u2)new_index;
3317 }
3318 } // end for each local variable table entry
3319 } // end if there are local variable table entries
3320
3321 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3322 } // end for each method
3323 } // end set_new_constant_pool()
3324
3325
3326 // Unevolving classes may point to methods of the_class directly
3327 // from their constant pool caches, itables, and/or vtables. We
3328 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3329 // to fix up these pointers.
3330
3331 // Adjust cpools and vtables closure
3332 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3333
3334 // This is a very busy routine. We don't want too much tracing
3335 // printed out.
3336 bool trace_name_printed = false;
3337 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3338
3339 // If the class being redefined is java.lang.Object, we need to fix all
3340 // array class vtables also
3341 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3342 k->vtable().adjust_method_entries(the_class, &trace_name_printed);
3343
3344 } else if (k->is_instance_klass()) {
3345 HandleMark hm(_thread);
3346 InstanceKlass *ik = InstanceKlass::cast(k);
3347
3348 // HotSpot specific optimization! HotSpot does not currently
3349 // support delegation from the bootstrap class loader to a
3350 // user-defined class loader. This means that if the bootstrap
3351 // class loader is the initiating class loader, then it will also
3352 // be the defining class loader. This also means that classes
3353 // loaded by the bootstrap class loader cannot refer to classes
3354 // loaded by a user-defined class loader. Note: a user-defined
3355 // class loader can delegate to the bootstrap class loader.
3356 //
3357 // If the current class being redefined has a user-defined class
3358 // loader as its defining class loader, then we can skip all
3359 // classes loaded by the bootstrap class loader.
3360 bool is_user_defined = (_the_class->class_loader() != NULL);
3361 if (is_user_defined && ik->class_loader() == NULL) {
3362 return;
3363 }
3364
3365 // Fix the vtable embedded in the_class and subclasses of the_class,
3366 // if one exists. We discard scratch_class and we don't keep an
3367 // InstanceKlass around to hold obsolete methods so we don't have
3368 // any other InstanceKlass embedded vtables to update. The vtable
3369 // holds the Method*s for virtual (but not final) methods.
3370 // Default methods, or concrete methods in interfaces are stored
3371 // in the vtable, so if an interface changes we need to check
3372 // adjust_method_entries() for every InstanceKlass, which will also
3373 // adjust the default method vtable indices.
3374 // We also need to adjust any default method entries that are
3375 // not yet in the vtable, because the vtable setup is in progress.
3376 // This must be done after we adjust the default_methods and
3377 // default_vtable_indices for methods already in the vtable.
3378 // If redefining Unsafe, walk all the vtables looking for entries.
3379 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3380 || _the_class == SystemDictionary::internal_Unsafe_klass()
3381 || ik->is_subtype_of(_the_class))) {
3382 // ik->vtable() creates a wrapper object; rm cleans it up
3383 ResourceMark rm(_thread);
3384
3385 ik->vtable().adjust_method_entries(the_class, &trace_name_printed);
3386 ik->adjust_default_methods(the_class, &trace_name_printed);
3387 }
3388
3389 // If the current class has an itable and we are either redefining an
3390 // interface or if the current class is a subclass of the_class, then
3391 // we potentially have to fix the itable. If we are redefining an
3392 // interface, then we have to call adjust_method_entries() for
3393 // every InstanceKlass that has an itable since there isn't a
3394 // subclass relationship between an interface and an InstanceKlass.
3395 // If redefining Unsafe, walk all the itables looking for entries.
3396 if (ik->itable_length() > 0 && (_the_class->is_interface()
3397 || _the_class == SystemDictionary::internal_Unsafe_klass()
3398 || ik->is_subclass_of(_the_class))) {
3399 ResourceMark rm(_thread);
3400 ik->itable().adjust_method_entries(the_class, &trace_name_printed);
3401 }
3402
3403 // The constant pools in other classes (other_cp) can refer to
3404 // methods in the_class. We have to update method information in
3405 // other_cp's cache. If other_cp has a previous version, then we
3406 // have to repeat the process for each previous version. The
3407 // constant pool cache holds the Method*s for non-virtual
3408 // methods and for virtual, final methods.
3409 //
3410 // Special case: if the current class is the_class, then new_cp
3411 // has already been attached to the_class and old_cp has already
3412 // been added as a previous version. The new_cp doesn't have any
3413 // cached references to old methods so it doesn't need to be
3414 // updated. We can simply start with the previous version(s) in
3415 // that case.
3416 constantPoolHandle other_cp;
3417 ConstantPoolCache* cp_cache;
3418
3419 if (ik != _the_class) {
3420 // this klass' constant pool cache may need adjustment
3421 other_cp = constantPoolHandle(ik->constants());
3422 cp_cache = other_cp->cache();
3423 if (cp_cache != NULL) {
3424 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3425 }
3426 }
3427
3428 // the previous versions' constant pool caches may need adjustment
3429 for (InstanceKlass* pv_node = ik->previous_versions();
3430 pv_node != NULL;
3431 pv_node = pv_node->previous_versions()) {
3432 cp_cache = pv_node->constants()->cache();
3433 if (cp_cache != NULL) {
3434 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3435 }
3436 }
3437 }
3438 }
3439
3440 // Clean method data for this class
3441 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3442 if (k->is_instance_klass()) {
3443 InstanceKlass *ik = InstanceKlass::cast(k);
3444 // Clean MethodData of this class's methods so they don't refer to
3445 // old methods that are no longer running.
3446 Array<Method*>* methods = ik->methods();
3447 int num_methods = methods->length();
3448 for (int index = 0; index < num_methods; ++index) {
3449 if (methods->at(index)->method_data() != NULL) {
3450 methods->at(index)->method_data()->clean_weak_method_links();
3451 }
3452 }
3453 }
3454 }
3455
3456 void VM_RedefineClasses::update_jmethod_ids() {
3457 for (int j = 0; j < _matching_methods_length; ++j) {
3458 Method* old_method = _matching_old_methods[j];
3459 jmethodID jmid = old_method->find_jmethod_id_or_null();
3460 if (jmid != NULL) {
3461 // There is a jmethodID, change it to point to the new method
3462 methodHandle new_method_h(_matching_new_methods[j]);
3463 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3464 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3465 "should be replaced");
3466 }
3467 }
3468 }
3469
3470 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3471 int emcp_method_count = 0;
3472 int obsolete_count = 0;
3473 int old_index = 0;
3474 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3475 Method* old_method = _matching_old_methods[j];
3476 Method* new_method = _matching_new_methods[j];
3477 Method* old_array_method;
3478
3479 // Maintain an old_index into the _old_methods array by skipping
3480 // deleted methods
3481 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3482 ++old_index;
3483 }
3484
3485 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3486 // The EMCP definition from JSR-163 requires the bytecodes to be
3487 // the same with the exception of constant pool indices which may
3488 // differ. However, the constants referred to by those indices
3489 // must be the same.
3490 //
3491 // We use methods_EMCP() for comparison since constant pool
3492 // merging can remove duplicate constant pool entries that were
3493 // present in the old method and removed from the rewritten new
3494 // method. A faster binary comparison function would consider the
3495 // old and new methods to be different when they are actually
3496 // EMCP.
3497 //
3498 // The old and new methods are EMCP and you would think that we
3499 // could get rid of one of them here and now and save some space.
3500 // However, the concept of EMCP only considers the bytecodes and
3501 // the constant pool entries in the comparison. Other things,
3502 // e.g., the line number table (LNT) or the local variable table
3503 // (LVT) don't count in the comparison. So the new (and EMCP)
3504 // method can have a new LNT that we need so we can't just
3505 // overwrite the new method with the old method.
3506 //
3507 // When this routine is called, we have already attached the new
3508 // methods to the_class so the old methods are effectively
3509 // overwritten. However, if an old method is still executing,
3510 // then the old method cannot be collected until sometime after
3511 // the old method call has returned. So the overwriting of old
3512 // methods by new methods will save us space except for those
3513 // (hopefully few) old methods that are still executing.
3514 //
3515 // A method refers to a ConstMethod* and this presents another
3516 // possible avenue to space savings. The ConstMethod* in the
3517 // new method contains possibly new attributes (LNT, LVT, etc).
3518 // At first glance, it seems possible to save space by replacing
3519 // the ConstMethod* in the old method with the ConstMethod*
3520 // from the new method. The old and new methods would share the
3521 // same ConstMethod* and we would save the space occupied by
3522 // the old ConstMethod*. However, the ConstMethod* contains
3523 // a back reference to the containing method. Sharing the
3524 // ConstMethod* between two methods could lead to confusion in
3525 // the code that uses the back reference. This would lead to
3526 // brittle code that could be broken in non-obvious ways now or
3527 // in the future.
3528 //
3529 // Another possibility is to copy the ConstMethod* from the new
3530 // method to the old method and then overwrite the new method with
3531 // the old method. Since the ConstMethod* contains the bytecodes
3532 // for the method embedded in the oop, this option would change
3533 // the bytecodes out from under any threads executing the old
3534 // method and make the thread's bcp invalid. Since EMCP requires
3535 // that the bytecodes be the same modulo constant pool indices, it
3536 // is straight forward to compute the correct new bcp in the new
3537 // ConstMethod* from the old bcp in the old ConstMethod*. The
3538 // time consuming part would be searching all the frames in all
3539 // of the threads to find all of the calls to the old method.
3540 //
3541 // It looks like we will have to live with the limited savings
3542 // that we get from effectively overwriting the old methods
3543 // when the new methods are attached to the_class.
3544
3545 // Count number of methods that are EMCP. The method will be marked
3546 // old but not obsolete if it is EMCP.
3547 emcp_method_count++;
3548
3549 // An EMCP method is _not_ obsolete. An obsolete method has a
3550 // different jmethodID than the current method. An EMCP method
3551 // has the same jmethodID as the current method. Having the
3552 // same jmethodID for all EMCP versions of a method allows for
3553 // a consistent view of the EMCP methods regardless of which
3554 // EMCP method you happen to have in hand. For example, a
3555 // breakpoint set in one EMCP method will work for all EMCP
3556 // versions of the method including the current one.
3557 } else {
3558 // mark obsolete methods as such
3559 old_method->set_is_obsolete();
3560 obsolete_count++;
3561
3562 // obsolete methods need a unique idnum so they become new entries in
3563 // the jmethodID cache in InstanceKlass
3564 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3565 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3566 if (num != ConstMethod::UNSET_IDNUM) {
3567 old_method->set_method_idnum(num);
3568 }
3569
3570 // With tracing we try not to "yack" too much. The position of
3571 // this trace assumes there are fewer obsolete methods than
3572 // EMCP methods.
3573 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3574 ResourceMark rm;
3575 log_trace(redefine, class, obsolete, mark)
3576 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3577 }
3578 }
3579 old_method->set_is_old();
3580 }
3581 for (int i = 0; i < _deleted_methods_length; ++i) {
3582 Method* old_method = _deleted_methods[i];
3583
3584 assert(!old_method->has_vtable_index(),
3585 "cannot delete methods with vtable entries");;
3586
3587 // Mark all deleted methods as old, obsolete and deleted
3588 old_method->set_is_deleted();
3589 old_method->set_is_old();
3590 old_method->set_is_obsolete();
3591 ++obsolete_count;
3592 // With tracing we try not to "yack" too much. The position of
3593 // this trace assumes there are fewer obsolete methods than
3594 // EMCP methods.
3595 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3596 ResourceMark rm;
3597 log_trace(redefine, class, obsolete, mark)
3598 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3599 }
3600 }
3601 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3602 "sanity check");
3603 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3604 return emcp_method_count;
3605 }
3606
3607 // This internal class transfers the native function registration from old methods
3608 // to new methods. It is designed to handle both the simple case of unchanged
3609 // native methods and the complex cases of native method prefixes being added and/or
3610 // removed.
3611 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3612 //
3613 // This class is used after the new methods have been installed in "the_class".
3614 //
3615 // So, for example, the following must be handled. Where 'm' is a method and
3616 // a number followed by an underscore is a prefix.
3617 //
3618 // Old Name New Name
3619 // Simple transfer to new method m -> m
3620 // Add prefix m -> 1_m
3621 // Remove prefix 1_m -> m
3622 // Simultaneous add of prefixes m -> 3_2_1_m
3623 // Simultaneous removal of prefixes 3_2_1_m -> m
3624 // Simultaneous add and remove 1_m -> 2_m
3625 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3626 //
3627 class TransferNativeFunctionRegistration {
3628 private:
3629 InstanceKlass* the_class;
3630 int prefix_count;
3631 char** prefixes;
3632
3633 // Recursively search the binary tree of possibly prefixed method names.
3634 // Iteration could be used if all agents were well behaved. Full tree walk is
3635 // more resilent to agents not cleaning up intermediate methods.
3636 // Branch at each depth in the binary tree is:
3637 // (1) without the prefix.
3638 // (2) with the prefix.
3639 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3640 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3641 Symbol* signature) {
3642 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3643 if (name_symbol != NULL) {
3644 Method* method = the_class->lookup_method(name_symbol, signature);
3645 if (method != NULL) {
3646 // Even if prefixed, intermediate methods must exist.
3647 if (method->is_native()) {
3648 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3649 return method;
3650 }
3651 if (depth < prefix_count) {
3652 // Try applying further prefixes (other than this one).
3653 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3654 if (method != NULL) {
3655 return method; // found
3656 }
3657
3658 // Try adding this prefix to the method name and see if it matches
3659 // another method name.
3660 char* prefix = prefixes[depth];
3661 size_t prefix_len = strlen(prefix);
3662 size_t trial_len = name_len + prefix_len;
3663 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3664 strcpy(trial_name_str, prefix);
3665 strcat(trial_name_str, name_str);
3666 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3667 signature);
3668 if (method != NULL) {
3669 // If found along this branch, it was prefixed, mark as such
3670 method->set_is_prefixed_native();
3671 return method; // found
3672 }
3673 }
3674 }
3675 }
3676 return NULL; // This whole branch bore nothing
3677 }
3678
3679 // Return the method name with old prefixes stripped away.
3680 char* method_name_without_prefixes(Method* method) {
3681 Symbol* name = method->name();
3682 char* name_str = name->as_utf8();
3683
3684 // Old prefixing may be defunct, strip prefixes, if any.
3685 for (int i = prefix_count-1; i >= 0; i--) {
3686 char* prefix = prefixes[i];
3687 size_t prefix_len = strlen(prefix);
3688 if (strncmp(prefix, name_str, prefix_len) == 0) {
3689 name_str += prefix_len;
3690 }
3691 }
3692 return name_str;
3693 }
3694
3695 // Strip any prefixes off the old native method, then try to find a
3696 // (possibly prefixed) new native that matches it.
3697 Method* strip_and_search_for_new_native(Method* method) {
3698 ResourceMark rm;
3699 char* name_str = method_name_without_prefixes(method);
3700 return search_prefix_name_space(0, name_str, strlen(name_str),
3701 method->signature());
3702 }
3703
3704 public:
3705
3706 // Construct a native method transfer processor for this class.
3707 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3708 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3709
3710 the_class = _the_class;
3711 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3712 }
3713
3714 // Attempt to transfer any of the old or deleted methods that are native
3715 void transfer_registrations(Method** old_methods, int methods_length) {
3716 for (int j = 0; j < methods_length; j++) {
3717 Method* old_method = old_methods[j];
3718
3719 if (old_method->is_native() && old_method->has_native_function()) {
3720 Method* new_method = strip_and_search_for_new_native(old_method);
3721 if (new_method != NULL) {
3722 // Actually set the native function in the new method.
3723 // Redefine does not send events (except CFLH), certainly not this
3724 // behind the scenes re-registration.
3725 new_method->set_native_function(old_method->native_function(),
3726 !Method::native_bind_event_is_interesting);
3727 }
3728 }
3729 }
3730 }
3731 };
3732
3733 // Don't lose the association between a native method and its JNI function.
3734 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3735 TransferNativeFunctionRegistration transfer(the_class);
3736 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3737 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3738 }
3739
3740 // Deoptimize all compiled code that depends on this class.
3741 //
3742 // If the can_redefine_classes capability is obtained in the onload
3743 // phase then the compiler has recorded all dependencies from startup.
3744 // In that case we need only deoptimize and throw away all compiled code
3745 // that depends on the class.
3746 //
3747 // If can_redefine_classes is obtained sometime after the onload
3748 // phase then the dependency information may be incomplete. In that case
3749 // the first call to RedefineClasses causes all compiled code to be
3750 // thrown away. As can_redefine_classes has been obtained then
3751 // all future compilations will record dependencies so second and
3752 // subsequent calls to RedefineClasses need only throw away code
3753 // that depends on the class.
3754 //
3755 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3756 assert_locked_or_safepoint(Compile_lock);
3757
3758 // All dependencies have been recorded from startup or this is a second or
3759 // subsequent use of RedefineClasses
3760 if (JvmtiExport::all_dependencies_are_recorded()) {
3761 CodeCache::flush_evol_dependents_on(ik);
3762 } else {
3763 CodeCache::mark_all_nmethods_for_deoptimization();
3764
3765 ResourceMark rm(THREAD);
3766 DeoptimizationMarker dm;
3767
3768 // Deoptimize all activations depending on marked nmethods
3769 Deoptimization::deoptimize_dependents();
3770
3771 // Make the dependent methods not entrant
3772 CodeCache::make_marked_nmethods_not_entrant();
3773
3774 // From now on we know that the dependency information is complete
3775 JvmtiExport::set_all_dependencies_are_recorded(true);
3776 }
3777 }
3778
3779 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3780 Method* old_method;
3781 Method* new_method;
3782
3783 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3784 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3785 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3786 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3787
3788 _matching_methods_length = 0;
3789 _deleted_methods_length = 0;
3790 _added_methods_length = 0;
3791
3792 int nj = 0;
3793 int oj = 0;
3794 while (true) {
3795 if (oj >= _old_methods->length()) {
3796 if (nj >= _new_methods->length()) {
3797 break; // we've looked at everything, done
3798 }
3799 // New method at the end
3800 new_method = _new_methods->at(nj);
3801 _added_methods[_added_methods_length++] = new_method;
3802 ++nj;
3803 } else if (nj >= _new_methods->length()) {
3804 // Old method, at the end, is deleted
3805 old_method = _old_methods->at(oj);
3806 _deleted_methods[_deleted_methods_length++] = old_method;
3807 ++oj;
3808 } else {
3809 old_method = _old_methods->at(oj);
3810 new_method = _new_methods->at(nj);
3811 if (old_method->name() == new_method->name()) {
3812 if (old_method->signature() == new_method->signature()) {
3813 _matching_old_methods[_matching_methods_length ] = old_method;
3814 _matching_new_methods[_matching_methods_length++] = new_method;
3815 ++nj;
3816 ++oj;
3817 } else {
3818 // added overloaded have already been moved to the end,
3819 // so this is a deleted overloaded method
3820 _deleted_methods[_deleted_methods_length++] = old_method;
3821 ++oj;
3822 }
3823 } else { // names don't match
3824 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3825 // new method
3826 _added_methods[_added_methods_length++] = new_method;
3827 ++nj;
3828 } else {
3829 // deleted method
3830 _deleted_methods[_deleted_methods_length++] = old_method;
3831 ++oj;
3832 }
3833 }
3834 }
3835 }
3836 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3837 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3838 }
3839
3840
3841 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3842 InstanceKlass* scratch_class) {
3843 // Swap annotation fields values
3844 Annotations* old_annotations = the_class->annotations();
3845 the_class->set_annotations(scratch_class->annotations());
3846 scratch_class->set_annotations(old_annotations);
3847 }
3848
3849
3850 // Install the redefinition of a class:
3851 // - house keeping (flushing breakpoints and caches, deoptimizing
3852 // dependent compiled code)
3853 // - replacing parts in the_class with parts from scratch_class
3854 // - adding a weak reference to track the obsolete but interesting
3855 // parts of the_class
3856 // - adjusting constant pool caches and vtables in other classes
3857 // that refer to methods in the_class. These adjustments use the
3858 // ClassLoaderDataGraph::classes_do() facility which only allows
3859 // a helper method to be specified. The interesting parameters
3860 // that we would like to pass to the helper method are saved in
3861 // static global fields in the VM operation.
3862 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3863 InstanceKlass* scratch_class, TRAPS) {
3864
3865 HandleMark hm(THREAD); // make sure handles from this call are freed
3866
3867 if (log_is_enabled(Info, redefine, class, timer)) {
3868 _timer_rsc_phase1.start();
3869 }
3870
3871 InstanceKlass* the_class = get_ik(the_jclass);
3872
3873 // Remove all breakpoints in methods of this class
3874 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3875 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3876
3877 // Deoptimize all compiled code that depends on this class
3878 flush_dependent_code(the_class, THREAD);
3879
3880 _old_methods = the_class->methods();
3881 _new_methods = scratch_class->methods();
3882 _the_class = the_class;
3883 compute_added_deleted_matching_methods();
3884 update_jmethod_ids();
3885
3886 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
3887
3888 // Attach new constant pool to the original klass. The original
3889 // klass still refers to the old constant pool (for now).
3890 scratch_class->constants()->set_pool_holder(the_class);
3891
3892 #if 0
3893 // In theory, with constant pool merging in place we should be able
3894 // to save space by using the new, merged constant pool in place of
3895 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3896 // the klass version we are replacing now and any constant pool(s) in
3897 // previous versions of klass. Nice theory, doesn't work in practice.
3898 // When this code is enabled, even simple programs throw NullPointer
3899 // exceptions. I'm guessing that this is caused by some constant pool
3900 // cache difference between the new, merged constant pool and the
3901 // constant pool that was just being used by the klass. I'm keeping
3902 // this code around to archive the idea, but the code has to remain
3903 // disabled for now.
3904
3905 // Attach each old method to the new constant pool. This can be
3906 // done here since we are past the bytecode verification and
3907 // constant pool optimization phases.
3908 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3909 Method* method = _old_methods->at(i);
3910 method->set_constants(scratch_class->constants());
3911 }
3912
3913 // NOTE: this doesn't work because you can redefine the same class in two
3914 // threads, each getting their own constant pool data appended to the
3915 // original constant pool. In order for the new methods to work when they
3916 // become old methods, they need to keep their updated copy of the constant pool.
3917
3918 {
3919 // walk all previous versions of the klass
3920 InstanceKlass *ik = the_class;
3921 PreviousVersionWalker pvw(ik);
3922 do {
3923 ik = pvw.next_previous_version();
3924 if (ik != NULL) {
3925
3926 // attach previous version of klass to the new constant pool
3927 ik->set_constants(scratch_class->constants());
3928
3929 // Attach each method in the previous version of klass to the
3930 // new constant pool
3931 Array<Method*>* prev_methods = ik->methods();
3932 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3933 Method* method = prev_methods->at(i);
3934 method->set_constants(scratch_class->constants());
3935 }
3936 }
3937 } while (ik != NULL);
3938 }
3939 #endif
3940
3941 // Replace methods and constantpool
3942 the_class->set_methods(_new_methods);
3943 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3944 // and to be able to undo operation easily.
3945
3946 Array<int>* old_ordering = the_class->method_ordering();
3947 the_class->set_method_ordering(scratch_class->method_ordering());
3948 scratch_class->set_method_ordering(old_ordering);
3949
3950 ConstantPool* old_constants = the_class->constants();
3951 the_class->set_constants(scratch_class->constants());
3952 scratch_class->set_constants(old_constants); // See the previous comment.
3953 #if 0
3954 // We are swapping the guts of "the new class" with the guts of "the
3955 // class". Since the old constant pool has just been attached to "the
3956 // new class", it seems logical to set the pool holder in the old
3957 // constant pool also. However, doing this will change the observable
3958 // class hierarchy for any old methods that are still executing. A
3959 // method can query the identity of its "holder" and this query uses
3960 // the method's constant pool link to find the holder. The change in
3961 // holding class from "the class" to "the new class" can confuse
3962 // things.
3963 //
3964 // Setting the old constant pool's holder will also cause
3965 // verification done during vtable initialization below to fail.
3966 // During vtable initialization, the vtable's class is verified to be
3967 // a subtype of the method's holder. The vtable's class is "the
3968 // class" and the method's holder is gotten from the constant pool
3969 // link in the method itself. For "the class"'s directly implemented
3970 // methods, the method holder is "the class" itself (as gotten from
3971 // the new constant pool). The check works fine in this case. The
3972 // check also works fine for methods inherited from super classes.
3973 //
3974 // Miranda methods are a little more complicated. A miranda method is
3975 // provided by an interface when the class implementing the interface
3976 // does not provide its own method. These interfaces are implemented
3977 // internally as an InstanceKlass. These special instanceKlasses
3978 // share the constant pool of the class that "implements" the
3979 // interface. By sharing the constant pool, the method holder of a
3980 // miranda method is the class that "implements" the interface. In a
3981 // non-redefine situation, the subtype check works fine. However, if
3982 // the old constant pool's pool holder is modified, then the check
3983 // fails because there is no class hierarchy relationship between the
3984 // vtable's class and "the new class".
3985
3986 old_constants->set_pool_holder(scratch_class());
3987 #endif
3988
3989 // track number of methods that are EMCP for add_previous_version() call below
3990 int emcp_method_count = check_methods_and_mark_as_obsolete();
3991 transfer_old_native_function_registrations(the_class);
3992
3993 // The class file bytes from before any retransformable agents mucked
3994 // with them was cached on the scratch class, move to the_class.
3995 // Note: we still want to do this if nothing needed caching since it
3996 // should get cleared in the_class too.
3997 if (the_class->get_cached_class_file() == 0) {
3998 // the_class doesn't have a cache yet so copy it
3999 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4000 }
4001 else if (scratch_class->get_cached_class_file() !=
4002 the_class->get_cached_class_file()) {
4003 // The same class can be present twice in the scratch classes list or there
4004 // are multiple concurrent RetransformClasses calls on different threads.
4005 // In such cases we have to deallocate scratch_class cached_class_file.
4006 os::free(scratch_class->get_cached_class_file());
4007 }
4008
4009 // NULL out in scratch class to not delete twice. The class to be redefined
4010 // always owns these bytes.
4011 scratch_class->set_cached_class_file(NULL);
4012
4013 // Replace inner_classes
4014 Array<u2>* old_inner_classes = the_class->inner_classes();
4015 the_class->set_inner_classes(scratch_class->inner_classes());
4016 scratch_class->set_inner_classes(old_inner_classes);
4017
4018 // Initialize the vtable and interface table after
4019 // methods have been rewritten
4020 {
4021 ResourceMark rm(THREAD);
4022 // no exception should happen here since we explicitly
4023 // do not check loader constraints.
4024 // compare_and_normalize_class_versions has already checked:
4025 // - classloaders unchanged, signatures unchanged
4026 // - all instanceKlasses for redefined classes reused & contents updated
4027 the_class->vtable().initialize_vtable(false, THREAD);
4028 the_class->itable().initialize_itable(false, THREAD);
4029 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4030 }
4031
4032 // Leave arrays of jmethodIDs and itable index cache unchanged
4033
4034 // Copy the "source file name" attribute from new class version
4035 the_class->set_source_file_name_index(
4036 scratch_class->source_file_name_index());
4037
4038 // Copy the "source debug extension" attribute from new class version
4039 the_class->set_source_debug_extension(
4040 scratch_class->source_debug_extension(),
4041 scratch_class->source_debug_extension() == NULL ? 0 :
4042 (int)strlen(scratch_class->source_debug_extension()));
4043
4044 // Use of javac -g could be different in the old and the new
4045 if (scratch_class->access_flags().has_localvariable_table() !=
4046 the_class->access_flags().has_localvariable_table()) {
4047
4048 AccessFlags flags = the_class->access_flags();
4049 if (scratch_class->access_flags().has_localvariable_table()) {
4050 flags.set_has_localvariable_table();
4051 } else {
4052 flags.clear_has_localvariable_table();
4053 }
4054 the_class->set_access_flags(flags);
4055 }
4056
4057 swap_annotations(the_class, scratch_class);
4058
4059 // Replace minor version number of class file
4060 u2 old_minor_version = the_class->minor_version();
4061 the_class->set_minor_version(scratch_class->minor_version());
4062 scratch_class->set_minor_version(old_minor_version);
4063
4064 // Replace major version number of class file
4065 u2 old_major_version = the_class->major_version();
4066 the_class->set_major_version(scratch_class->major_version());
4067 scratch_class->set_major_version(old_major_version);
4068
4069 // Replace CP indexes for class and name+type of enclosing method
4070 u2 old_class_idx = the_class->enclosing_method_class_index();
4071 u2 old_method_idx = the_class->enclosing_method_method_index();
4072 the_class->set_enclosing_method_indices(
4073 scratch_class->enclosing_method_class_index(),
4074 scratch_class->enclosing_method_method_index());
4075 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4076
4077 // Replace fingerprint data
4078 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4079 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4080
4081 the_class->set_has_been_redefined();
4082
4083 if (!the_class->should_be_initialized()) {
4084 // Class was already initialized, so AOT has only seen the original version.
4085 // We need to let AOT look at it again.
4086 AOTLoader::load_for_klass(the_class, THREAD);
4087 }
4088
4089 // keep track of previous versions of this class
4090 the_class->add_previous_version(scratch_class, emcp_method_count);
4091
4092 _timer_rsc_phase1.stop();
4093 if (log_is_enabled(Info, redefine, class, timer)) {
4094 _timer_rsc_phase2.start();
4095 }
4096
4097 // Adjust constantpool caches and vtables for all classes
4098 // that reference methods of the evolved class.
4099 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4100 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4101
4102 if (the_class->oop_map_cache() != NULL) {
4103 // Flush references to any obsolete methods from the oop map cache
4104 // so that obsolete methods are not pinned.
4105 the_class->oop_map_cache()->flush_obsolete_entries();
4106 }
4107
4108 increment_class_counter((InstanceKlass *)the_class, THREAD);
4109 {
4110 ResourceMark rm(THREAD);
4111 // increment the classRedefinedCount field in the_class and in any
4112 // direct and indirect subclasses of the_class
4113 log_info(redefine, class, load)
4114 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4115 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4116 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4117 the_class->external_name(),
4118 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4119
4120 }
4121 _timer_rsc_phase2.stop();
4122 } // end redefine_single_class()
4123
4124
4125 // Increment the classRedefinedCount field in the specific InstanceKlass
4126 // and in all direct and indirect subclasses.
4127 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4128 oop class_mirror = ik->java_mirror();
4129 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4130 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4131 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4132
4133 if (class_oop != _the_class) {
4134 // _the_class count is printed at end of redefine_single_class()
4135 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4136 }
4137
4138 for (Klass *subk = ik->subklass(); subk != NULL;
4139 subk = subk->next_sibling()) {
4140 if (subk->is_instance_klass()) {
4141 // Only update instanceKlasses
4142 InstanceKlass *subik = InstanceKlass::cast(subk);
4143 // recursively do subclasses of the current subclass
4144 increment_class_counter(subik, THREAD);
4145 }
4146 }
4147 }
4148
4149 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4150 bool no_old_methods = true; // be optimistic
4151
4152 // Both array and instance classes have vtables.
4153 // a vtable should never contain old or obsolete methods
4154 ResourceMark rm(_thread);
4155 if (k->vtable_length() > 0 &&
4156 !k->vtable().check_no_old_or_obsolete_entries()) {
4157 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4158 log_trace(redefine, class, obsolete, metadata)
4159 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4160 k->signature_name());
4161 k->vtable().dump_vtable();
4162 }
4163 no_old_methods = false;
4164 }
4165
4166 if (k->is_instance_klass()) {
4167 HandleMark hm(_thread);
4168 InstanceKlass *ik = InstanceKlass::cast(k);
4169
4170 // an itable should never contain old or obsolete methods
4171 if (ik->itable_length() > 0 &&
4172 !ik->itable().check_no_old_or_obsolete_entries()) {
4173 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4174 log_trace(redefine, class, obsolete, metadata)
4175 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4176 ik->signature_name());
4177 ik->itable().dump_itable();
4178 }
4179 no_old_methods = false;
4180 }
4181
4182 // the constant pool cache should never contain non-deleted old or obsolete methods
4183 if (ik->constants() != NULL &&
4184 ik->constants()->cache() != NULL &&
4185 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4186 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4187 log_trace(redefine, class, obsolete, metadata)
4188 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4189 ik->signature_name());
4190 ik->constants()->cache()->dump_cache();
4191 }
4192 no_old_methods = false;
4193 }
4194 }
4195
4196 // print and fail guarantee if old methods are found.
4197 if (!no_old_methods) {
4198 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4199 dump_methods();
4200 } else {
4201 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4202 "to see more info about the following guarantee() failure.");
4203 }
4204 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4205 }
4206 }
4207
4208
4209 void VM_RedefineClasses::dump_methods() {
4210 int j;
4211 log_trace(redefine, class, dump)("_old_methods --");
4212 for (j = 0; j < _old_methods->length(); ++j) {
4213 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4214 Method* m = _old_methods->at(j);
4215 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4216 m->access_flags().print_on(&log_stream);
4217 log_stream.print(" -- ");
4218 m->print_name(&log_stream);
4219 log_stream.cr();
4220 }
4221 log_trace(redefine, class, dump)("_new_methods --");
4222 for (j = 0; j < _new_methods->length(); ++j) {
4223 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4224 Method* m = _new_methods->at(j);
4225 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4226 m->access_flags().print_on(&log_stream);
4227 log_stream.print(" -- ");
4228 m->print_name(&log_stream);
4229 log_stream.cr();
4230 }
4231 log_trace(redefine, class, dump)("_matching_methods --");
4232 for (j = 0; j < _matching_methods_length; ++j) {
4233 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4234 Method* m = _matching_old_methods[j];
4235 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4236 m->access_flags().print_on(&log_stream);
4237 log_stream.print(" -- ");
4238 m->print_name();
4239 log_stream.cr();
4240
4241 m = _matching_new_methods[j];
4242 log_stream.print(" (%5d) ", m->vtable_index());
4243 m->access_flags().print_on(&log_stream);
4244 log_stream.cr();
4245 }
4246 log_trace(redefine, class, dump)("_deleted_methods --");
4247 for (j = 0; j < _deleted_methods_length; ++j) {
4248 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4249 Method* m = _deleted_methods[j];
4250 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4251 m->access_flags().print_on(&log_stream);
4252 log_stream.print(" -- ");
4253 m->print_name(&log_stream);
4254 log_stream.cr();
4255 }
4256 log_trace(redefine, class, dump)("_added_methods --");
4257 for (j = 0; j < _added_methods_length; ++j) {
4258 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4259 Method* m = _added_methods[j];
4260 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4261 m->access_flags().print_on(&log_stream);
4262 log_stream.print(" -- ");
4263 m->print_name(&log_stream);
4264 log_stream.cr();
4265 }
4266 }
4267
4268 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4269 VM_Operation::print_on_error(st);
4270 if (_the_class != NULL) {
4271 ResourceMark rm;
4272 st->print_cr(", redefining class %s", _the_class->external_name());
4273 }
4274 }