1 /*
2 * Copyright (c) 2003, 2018, 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.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/jniHandles.inline.hpp"
51 #include "runtime/relocator.hpp"
52 #include "utilities/bitMap.inline.hpp"
53 #include "utilities/events.hpp"
54
55 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
56 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
57 Method** VM_RedefineClasses::_matching_old_methods = NULL;
58 Method** VM_RedefineClasses::_matching_new_methods = NULL;
59 Method** VM_RedefineClasses::_deleted_methods = NULL;
60 Method** VM_RedefineClasses::_added_methods = NULL;
61 int VM_RedefineClasses::_matching_methods_length = 0;
62 int VM_RedefineClasses::_deleted_methods_length = 0;
63 int VM_RedefineClasses::_added_methods_length = 0;
64 Klass* VM_RedefineClasses::_the_class = NULL;
65
66
67 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
68 const jvmtiClassDefinition *class_defs,
69 JvmtiClassLoadKind class_load_kind) {
70 _class_count = class_count;
71 _class_defs = class_defs;
72 _class_load_kind = class_load_kind;
73 _any_class_has_resolved_methods = false;
74 _res = JVMTI_ERROR_NONE;
75 }
76
77 static inline InstanceKlass* get_ik(jclass def) {
78 oop mirror = JNIHandles::resolve_non_null(def);
79 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
80 }
81
82 // If any of the classes are being redefined, wait
83 // Parallel constant pool merging leads to indeterminate constant pools.
84 void VM_RedefineClasses::lock_classes() {
85 MutexLocker ml(RedefineClasses_lock);
86 bool has_redefined;
87 do {
88 has_redefined = false;
89 // Go through classes each time until none are being redefined.
90 for (int i = 0; i < _class_count; i++) {
91 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
92 RedefineClasses_lock->wait();
93 has_redefined = true;
94 break; // for loop
95 }
96 }
97 } while (has_redefined);
98 for (int i = 0; i < _class_count; i++) {
99 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
100 }
101 RedefineClasses_lock->notify_all();
102 }
103
104 void VM_RedefineClasses::unlock_classes() {
105 MutexLocker ml(RedefineClasses_lock);
106 for (int i = 0; i < _class_count; i++) {
107 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
108 "should be being redefined to get here");
109 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
110 }
111 RedefineClasses_lock->notify_all();
112 }
113
114 bool VM_RedefineClasses::doit_prologue() {
115 if (_class_count == 0) {
116 _res = JVMTI_ERROR_NONE;
117 return false;
118 }
119 if (_class_defs == NULL) {
120 _res = JVMTI_ERROR_NULL_POINTER;
121 return false;
122 }
123 for (int i = 0; i < _class_count; i++) {
124 if (_class_defs[i].klass == NULL) {
125 _res = JVMTI_ERROR_INVALID_CLASS;
126 return false;
127 }
128 if (_class_defs[i].class_byte_count == 0) {
129 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
130 return false;
131 }
132 if (_class_defs[i].class_bytes == NULL) {
133 _res = JVMTI_ERROR_NULL_POINTER;
134 return false;
135 }
136
137 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
138 // classes for primitives and arrays and vm anonymous classes cannot be redefined
139 // check here so following code can assume these classes are InstanceKlass
140 if (!is_modifiable_class(mirror)) {
141 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
142 return false;
143 }
144 }
145
146 // Start timer after all the sanity checks; not quite accurate, but
147 // better than adding a bunch of stop() calls.
148 if (log_is_enabled(Info, redefine, class, timer)) {
149 _timer_vm_op_prologue.start();
150 }
151
152 lock_classes();
153 // We first load new class versions in the prologue, because somewhere down the
154 // call chain it is required that the current thread is a Java thread.
155 _res = load_new_class_versions(Thread::current());
156 if (_res != JVMTI_ERROR_NONE) {
157 // free any successfully created classes, since none are redefined
158 for (int i = 0; i < _class_count; i++) {
159 if (_scratch_classes[i] != NULL) {
160 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
161 // Free the memory for this class at class unloading time. Not before
162 // because CMS might think this is still live.
163 InstanceKlass* ik = get_ik(_class_defs[i].klass);
164 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
165 // Don't double-free cached_class_file copied from the original class if error.
166 _scratch_classes[i]->set_cached_class_file(NULL);
167 }
168 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
169 }
170 }
171 // Free os::malloc allocated memory in load_new_class_version.
172 os::free(_scratch_classes);
173 _timer_vm_op_prologue.stop();
174 unlock_classes();
175 return false;
176 }
177
178 _timer_vm_op_prologue.stop();
179 return true;
180 }
181
182 void VM_RedefineClasses::doit() {
183 Thread *thread = Thread::current();
184
185 #if INCLUDE_CDS
186 if (UseSharedSpaces) {
187 // Sharing is enabled so we remap the shared readonly space to
188 // shared readwrite, private just in case we need to redefine
189 // a shared class. We do the remap during the doit() phase of
190 // the safepoint to be safer.
191 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
192 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
193 _res = JVMTI_ERROR_INTERNAL;
194 return;
195 }
196 }
197 #endif
198
199 // Mark methods seen on stack and everywhere else so old methods are not
200 // cleaned up if they're on the stack.
201 MetadataOnStackMark md_on_stack(true);
202 HandleMark hm(thread); // make sure any handles created are deleted
203 // before the stack walk again.
204
205 for (int i = 0; i < _class_count; i++) {
206 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
207 }
208
209 // Clean out MethodData pointing to old Method*
210 // Have to do this after all classes are redefined and all methods that
211 // are redefined are marked as old.
212 MethodDataCleaner clean_weak_method_links;
213 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
214
215 // JSR-292 support
216 if (_any_class_has_resolved_methods) {
217 bool trace_name_printed = false;
218 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
219 }
220
221 // Disable any dependent concurrent compilations
222 SystemDictionary::notice_modification();
223
224 // Set flag indicating that some invariants are no longer true.
225 // See jvmtiExport.hpp for detailed explanation.
226 JvmtiExport::set_has_redefined_a_class();
227
228 // check_class() is optionally called for product bits, but is
229 // always called for non-product bits.
230 #ifdef PRODUCT
231 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
232 #endif
233 log_trace(redefine, class, obsolete, metadata)("calling check_class");
234 CheckClass check_class(thread);
235 ClassLoaderDataGraph::classes_do(&check_class);
236 #ifdef PRODUCT
237 }
238 #endif
239 }
240
241 void VM_RedefineClasses::doit_epilogue() {
242 unlock_classes();
243
244 // Free os::malloc allocated memory.
245 os::free(_scratch_classes);
246
247 // Reset the_class to null for error printing.
248 _the_class = NULL;
249
250 if (log_is_enabled(Info, redefine, class, timer)) {
251 // Used to have separate timers for "doit" and "all", but the timer
252 // overhead skewed the measurements.
253 julong doit_time = _timer_rsc_phase1.milliseconds() +
254 _timer_rsc_phase2.milliseconds();
255 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
256
257 log_info(redefine, class, timer)
258 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
259 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
260 log_info(redefine, class, timer)
261 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
262 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
263 }
264 }
265
266 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
267 // classes for primitives cannot be redefined
268 if (java_lang_Class::is_primitive(klass_mirror)) {
269 return false;
270 }
271 Klass* k = java_lang_Class::as_Klass(klass_mirror);
272 // classes for arrays cannot be redefined
273 if (k == NULL || !k->is_instance_klass()) {
274 return false;
275 }
276
277 // Cannot redefine or retransform an anonymous class.
278 if (InstanceKlass::cast(k)->is_anonymous()) {
279 return false;
280 }
281 return true;
282 }
283
284 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
285 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
286 // direct CP entries, there is just the current entry to append. For
287 // indirect and double-indirect CP entries, there are zero or more
288 // referenced CP entries along with the current entry to append.
289 // Indirect and double-indirect CP entries are handled by recursive
290 // calls to append_entry() as needed. The referenced CP entries are
291 // always appended to *merge_cp_p before the referee CP entry. These
292 // referenced CP entries may already exist in *merge_cp_p in which case
293 // there is nothing extra to append and only the current entry is
294 // appended.
295 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
296 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
297 TRAPS) {
298
299 // append is different depending on entry tag type
300 switch (scratch_cp->tag_at(scratch_i).value()) {
301
302 // The old verifier is implemented outside the VM. It loads classes,
303 // but does not resolve constant pool entries directly so we never
304 // see Class entries here with the old verifier. Similarly the old
305 // verifier does not like Class entries in the input constant pool.
306 // The split-verifier is implemented in the VM so it can optionally
307 // and directly resolve constant pool entries to load classes. The
308 // split-verifier can accept either Class entries or UnresolvedClass
309 // entries in the input constant pool. We revert the appended copy
310 // back to UnresolvedClass so that either verifier will be happy
311 // with the constant pool entry.
312 //
313 // this is an indirect CP entry so it needs special handling
314 case JVM_CONSTANT_Class:
315 case JVM_CONSTANT_UnresolvedClass:
316 {
317 int name_i = scratch_cp->klass_name_index_at(scratch_i);
318 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
319 merge_cp_length_p, THREAD);
320
321 if (new_name_i != name_i) {
322 log_trace(redefine, class, constantpool)
323 ("Class entry@%d name_index change: %d to %d",
324 *merge_cp_length_p, name_i, new_name_i);
325 }
326
327 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
328 if (scratch_i != *merge_cp_length_p) {
329 // The new entry in *merge_cp_p is at a different index than
330 // the new entry in scratch_cp so we need to map the index values.
331 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
332 }
333 (*merge_cp_length_p)++;
334 } break;
335
336 // these are direct CP entries so they can be directly appended,
337 // but double and long take two constant pool entries
338 case JVM_CONSTANT_Double: // fall through
339 case JVM_CONSTANT_Long:
340 {
341 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
342 THREAD);
343
344 if (scratch_i != *merge_cp_length_p) {
345 // The new entry in *merge_cp_p is at a different index than
346 // the new entry in scratch_cp so we need to map the index values.
347 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
348 }
349 (*merge_cp_length_p) += 2;
350 } break;
351
352 // these are direct CP entries so they can be directly appended
353 case JVM_CONSTANT_Float: // fall through
354 case JVM_CONSTANT_Integer: // fall through
355 case JVM_CONSTANT_Utf8: // fall through
356
357 // This was an indirect CP entry, but it has been changed into
358 // Symbol*s so this entry can be directly appended.
359 case JVM_CONSTANT_String: // fall through
360 {
361 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
362 THREAD);
363
364 if (scratch_i != *merge_cp_length_p) {
365 // The new entry in *merge_cp_p is at a different index than
366 // the new entry in scratch_cp so we need to map the index values.
367 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
368 }
369 (*merge_cp_length_p)++;
370 } break;
371
372 // this is an indirect CP entry so it needs special handling
373 case JVM_CONSTANT_NameAndType:
374 {
375 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
376 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
377 merge_cp_length_p, THREAD);
378
379 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
380 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
381 merge_cp_p, merge_cp_length_p,
382 THREAD);
383
384 // If the referenced entries already exist in *merge_cp_p, then
385 // both new_name_ref_i and new_signature_ref_i will both be 0.
386 // In that case, all we are appending is the current entry.
387 if (new_name_ref_i != name_ref_i) {
388 log_trace(redefine, class, constantpool)
389 ("NameAndType entry@%d name_ref_index change: %d to %d",
390 *merge_cp_length_p, name_ref_i, new_name_ref_i);
391 }
392 if (new_signature_ref_i != signature_ref_i) {
393 log_trace(redefine, class, constantpool)
394 ("NameAndType entry@%d signature_ref_index change: %d to %d",
395 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
396 }
397
398 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
399 new_name_ref_i, new_signature_ref_i);
400 if (scratch_i != *merge_cp_length_p) {
401 // The new entry in *merge_cp_p is at a different index than
402 // the new entry in scratch_cp so we need to map the index values.
403 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
404 }
405 (*merge_cp_length_p)++;
406 } break;
407
408 // this is a double-indirect CP entry so it needs special handling
409 case JVM_CONSTANT_Fieldref: // fall through
410 case JVM_CONSTANT_InterfaceMethodref: // fall through
411 case JVM_CONSTANT_Methodref:
412 {
413 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
414 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
415 merge_cp_p, merge_cp_length_p, THREAD);
416
417 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
418 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
419 merge_cp_p, merge_cp_length_p, THREAD);
420
421 const char *entry_name = NULL;
422 switch (scratch_cp->tag_at(scratch_i).value()) {
423 case JVM_CONSTANT_Fieldref:
424 entry_name = "Fieldref";
425 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
426 new_name_and_type_ref_i);
427 break;
428 case JVM_CONSTANT_InterfaceMethodref:
429 entry_name = "IFMethodref";
430 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
431 new_klass_ref_i, new_name_and_type_ref_i);
432 break;
433 case JVM_CONSTANT_Methodref:
434 entry_name = "Methodref";
435 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
436 new_name_and_type_ref_i);
437 break;
438 default:
439 guarantee(false, "bad switch");
440 break;
441 }
442
443 if (klass_ref_i != new_klass_ref_i) {
444 log_trace(redefine, class, constantpool)
445 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
446 }
447 if (name_and_type_ref_i != new_name_and_type_ref_i) {
448 log_trace(redefine, class, constantpool)
449 ("%s entry@%d name_and_type_index changed: %d to %d",
450 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
451 }
452
453 if (scratch_i != *merge_cp_length_p) {
454 // The new entry in *merge_cp_p is at a different index than
455 // the new entry in scratch_cp so we need to map the index values.
456 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
457 }
458 (*merge_cp_length_p)++;
459 } break;
460
461 // this is an indirect CP entry so it needs special handling
462 case JVM_CONSTANT_MethodType:
463 {
464 int ref_i = scratch_cp->method_type_index_at(scratch_i);
465 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
466 merge_cp_length_p, THREAD);
467 if (new_ref_i != ref_i) {
468 log_trace(redefine, class, constantpool)
469 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
470 }
471 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
472 if (scratch_i != *merge_cp_length_p) {
473 // The new entry in *merge_cp_p is at a different index than
474 // the new entry in scratch_cp so we need to map the index values.
475 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
476 }
477 (*merge_cp_length_p)++;
478 } break;
479
480 // this is an indirect CP entry so it needs special handling
481 case JVM_CONSTANT_MethodHandle:
482 {
483 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
484 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
485 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
486 merge_cp_length_p, THREAD);
487 if (new_ref_i != ref_i) {
488 log_trace(redefine, class, constantpool)
489 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
490 }
491 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
492 if (scratch_i != *merge_cp_length_p) {
493 // The new entry in *merge_cp_p is at a different index than
494 // the new entry in scratch_cp so we need to map the index values.
495 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
496 }
497 (*merge_cp_length_p)++;
498 } break;
499
500 // this is an indirect CP entry so it needs special handling
501 case JVM_CONSTANT_Dynamic: // fall through
502 case JVM_CONSTANT_InvokeDynamic:
503 {
504 // Index of the bootstrap specifier in the operands array
505 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
506 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
507 merge_cp_length_p, THREAD);
508 // The bootstrap method NameAndType_info index
509 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
510 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
511 merge_cp_length_p, THREAD);
512 if (new_bs_i != old_bs_i) {
513 log_trace(redefine, class, constantpool)
514 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
515 *merge_cp_length_p, old_bs_i, new_bs_i);
516 }
517 if (new_ref_i != old_ref_i) {
518 log_trace(redefine, class, constantpool)
519 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
520 }
521
522 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
523 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
524 else
525 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
526 if (scratch_i != *merge_cp_length_p) {
527 // The new entry in *merge_cp_p is at a different index than
528 // the new entry in scratch_cp so we need to map the index values.
529 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
530 }
531 (*merge_cp_length_p)++;
532 } break;
533
534 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
535 // ClassIndex
536 case JVM_CONSTANT_ClassIndex: // fall through
537
538 // Invalid is used as the tag for the second constant pool entry
539 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
540 // not be seen by itself.
541 case JVM_CONSTANT_Invalid: // fall through
542
543 // At this stage, String could be here, but not StringIndex
544 case JVM_CONSTANT_StringIndex: // fall through
545
546 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
547 // here
548 case JVM_CONSTANT_UnresolvedClassInError: // fall through
549
550 default:
551 {
552 // leave a breadcrumb
553 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
554 ShouldNotReachHere();
555 } break;
556 } // end switch tag value
557 } // end append_entry()
558
559
560 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
561 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
562
563 int new_ref_i = ref_i;
564 bool match = (ref_i < *merge_cp_length_p) &&
565 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
566
567 if (!match) {
568 // forward reference in *merge_cp_p or not a direct match
569 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
570 if (found_i != 0) {
571 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
572 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
573 new_ref_i = found_i;
574 map_index(scratch_cp, ref_i, found_i);
575 } else {
576 // no match found so we have to append this entry to *merge_cp_p
577 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
578 // The above call to append_entry() can only append one entry
579 // so the post call query of *merge_cp_length_p is only for
580 // the sake of consistency.
581 new_ref_i = *merge_cp_length_p - 1;
582 }
583 }
584
585 return new_ref_i;
586 } // end find_or_append_indirect_entry()
587
588
589 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
590 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
591 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
592 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
593 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
594
595 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
596 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
597 merge_cp_length_p, THREAD);
598 if (new_ref_i != old_ref_i) {
599 log_trace(redefine, class, constantpool)
600 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
601 }
602
603 Array<u2>* merge_ops = (*merge_cp_p)->operands();
604 int new_bs_i = _operands_cur_length;
605 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
606 // However, the operand_offset_at(0) was set in the extend_operands() call.
607 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
608 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
609 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
610
611 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
612 merge_ops->at_put(new_base++, new_ref_i);
613 merge_ops->at_put(new_base++, argc);
614
615 for (int i = 0; i < argc; i++) {
616 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
617 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
618 merge_cp_length_p, THREAD);
619 merge_ops->at_put(new_base++, new_arg_ref_i);
620 if (new_arg_ref_i != old_arg_ref_i) {
621 log_trace(redefine, class, constantpool)
622 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
623 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
624 }
625 }
626 if (old_bs_i != _operands_cur_length) {
627 // The bootstrap specifier in *merge_cp_p is at a different index than
628 // that in scratch_cp so we need to map the index values.
629 map_operand_index(old_bs_i, new_bs_i);
630 }
631 _operands_cur_length++;
632 } // end append_operand()
633
634
635 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
636 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
637
638 int new_bs_i = old_bs_i; // bootstrap specifier index
639 bool match = (old_bs_i < _operands_cur_length) &&
640 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
641
642 if (!match) {
643 // forward reference in *merge_cp_p or not a direct match
644 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
645 _operands_cur_length, THREAD);
646 if (found_i != -1) {
647 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
648 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
649 new_bs_i = found_i;
650 map_operand_index(old_bs_i, found_i);
651 } else {
652 // no match found so we have to append this bootstrap specifier to *merge_cp_p
653 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
654 new_bs_i = _operands_cur_length - 1;
655 }
656 }
657 return new_bs_i;
658 } // end find_or_append_operand()
659
660
661 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
662 if (merge_cp->operands() == NULL) {
663 return;
664 }
665 // Shrink the merge_cp operands
666 merge_cp->shrink_operands(_operands_cur_length, CHECK);
667
668 if (log_is_enabled(Trace, redefine, class, constantpool)) {
669 // don't want to loop unless we are tracing
670 int count = 0;
671 for (int i = 1; i < _operands_index_map_p->length(); i++) {
672 int value = _operands_index_map_p->at(i);
673 if (value != -1) {
674 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
675 count++;
676 }
677 }
678 }
679 // Clean-up
680 _operands_index_map_p = NULL;
681 _operands_cur_length = 0;
682 _operands_index_map_count = 0;
683 } // end finalize_operands_merge()
684
685
686 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
687 InstanceKlass* the_class,
688 InstanceKlass* scratch_class) {
689 int i;
690
691 // Check superclasses, or rather their names, since superclasses themselves can be
692 // requested to replace.
693 // Check for NULL superclass first since this might be java.lang.Object
694 if (the_class->super() != scratch_class->super() &&
695 (the_class->super() == NULL || scratch_class->super() == NULL ||
696 the_class->super()->name() !=
697 scratch_class->super()->name())) {
698 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
699 }
700
701 // Check if the number, names and order of directly implemented interfaces are the same.
702 // I think in principle we should just check if the sets of names of directly implemented
703 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
704 // .java file, also changes in .class file) should not matter. However, comparing sets is
705 // technically a bit more difficult, and, more importantly, I am not sure at present that the
706 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
707 // rely on it somewhere.
708 Array<Klass*>* k_interfaces = the_class->local_interfaces();
709 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
710 int n_intfs = k_interfaces->length();
711 if (n_intfs != k_new_interfaces->length()) {
712 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
713 }
714 for (i = 0; i < n_intfs; i++) {
715 if (k_interfaces->at(i)->name() !=
716 k_new_interfaces->at(i)->name()) {
717 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
718 }
719 }
720
721 // Check whether class is in the error init state.
722 if (the_class->is_in_error_state()) {
723 // TBD #5057930: special error code is needed in 1.6
724 return JVMTI_ERROR_INVALID_CLASS;
725 }
726
727 // Check whether class modifiers are the same.
728 jushort old_flags = (jushort) the_class->access_flags().get_flags();
729 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
730 if (old_flags != new_flags) {
731 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
732 }
733
734 // Check if the number, names, types and order of fields declared in these classes
735 // are the same.
736 JavaFieldStream old_fs(the_class);
737 JavaFieldStream new_fs(scratch_class);
738 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
739 // access
740 old_flags = old_fs.access_flags().as_short();
741 new_flags = new_fs.access_flags().as_short();
742 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
743 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
744 }
745 // offset
746 if (old_fs.offset() != new_fs.offset()) {
747 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
748 }
749 // name and signature
750 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
751 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
752 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
753 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
754 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
755 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
756 }
757 }
758
759 // If both streams aren't done then we have a differing number of
760 // fields.
761 if (!old_fs.done() || !new_fs.done()) {
762 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
763 }
764
765 // Do a parallel walk through the old and new methods. Detect
766 // cases where they match (exist in both), have been added in
767 // the new methods, or have been deleted (exist only in the
768 // old methods). The class file parser places methods in order
769 // by method name, but does not order overloaded methods by
770 // signature. In order to determine what fate befell the methods,
771 // this code places the overloaded new methods that have matching
772 // old methods in the same order as the old methods and places
773 // new overloaded methods at the end of overloaded methods of
774 // that name. The code for this order normalization is adapted
775 // from the algorithm used in InstanceKlass::find_method().
776 // Since we are swapping out of order entries as we find them,
777 // we only have to search forward through the overloaded methods.
778 // Methods which are added and have the same name as an existing
779 // method (but different signature) will be put at the end of
780 // the methods with that name, and the name mismatch code will
781 // handle them.
782 Array<Method*>* k_old_methods(the_class->methods());
783 Array<Method*>* k_new_methods(scratch_class->methods());
784 int n_old_methods = k_old_methods->length();
785 int n_new_methods = k_new_methods->length();
786 Thread* thread = Thread::current();
787
788 int ni = 0;
789 int oi = 0;
790 while (true) {
791 Method* k_old_method;
792 Method* k_new_method;
793 enum { matched, added, deleted, undetermined } method_was = undetermined;
794
795 if (oi >= n_old_methods) {
796 if (ni >= n_new_methods) {
797 break; // we've looked at everything, done
798 }
799 // New method at the end
800 k_new_method = k_new_methods->at(ni);
801 method_was = added;
802 } else if (ni >= n_new_methods) {
803 // Old method, at the end, is deleted
804 k_old_method = k_old_methods->at(oi);
805 method_was = deleted;
806 } else {
807 // There are more methods in both the old and new lists
808 k_old_method = k_old_methods->at(oi);
809 k_new_method = k_new_methods->at(ni);
810 if (k_old_method->name() != k_new_method->name()) {
811 // Methods are sorted by method name, so a mismatch means added
812 // or deleted
813 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
814 method_was = added;
815 } else {
816 method_was = deleted;
817 }
818 } else if (k_old_method->signature() == k_new_method->signature()) {
819 // Both the name and signature match
820 method_was = matched;
821 } else {
822 // The name matches, but the signature doesn't, which means we have to
823 // search forward through the new overloaded methods.
824 int nj; // outside the loop for post-loop check
825 for (nj = ni + 1; nj < n_new_methods; nj++) {
826 Method* m = k_new_methods->at(nj);
827 if (k_old_method->name() != m->name()) {
828 // reached another method name so no more overloaded methods
829 method_was = deleted;
830 break;
831 }
832 if (k_old_method->signature() == m->signature()) {
833 // found a match so swap the methods
834 k_new_methods->at_put(ni, m);
835 k_new_methods->at_put(nj, k_new_method);
836 k_new_method = m;
837 method_was = matched;
838 break;
839 }
840 }
841
842 if (nj >= n_new_methods) {
843 // reached the end without a match; so method was deleted
844 method_was = deleted;
845 }
846 }
847 }
848
849 switch (method_was) {
850 case matched:
851 // methods match, be sure modifiers do too
852 old_flags = (jushort) k_old_method->access_flags().get_flags();
853 new_flags = (jushort) k_new_method->access_flags().get_flags();
854 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
855 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
856 }
857 {
858 u2 new_num = k_new_method->method_idnum();
859 u2 old_num = k_old_method->method_idnum();
860 if (new_num != old_num) {
861 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
862 if (idnum_owner != NULL) {
863 // There is already a method assigned this idnum -- switch them
864 // Take current and original idnum from the new_method
865 idnum_owner->set_method_idnum(new_num);
866 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
867 }
868 // Take current and original idnum from the old_method
869 k_new_method->set_method_idnum(old_num);
870 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
871 if (thread->has_pending_exception()) {
872 return JVMTI_ERROR_OUT_OF_MEMORY;
873 }
874 }
875 }
876 log_trace(redefine, class, normalize)
877 ("Method matched: new: %s [%d] == old: %s [%d]",
878 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
879 // advance to next pair of methods
880 ++oi;
881 ++ni;
882 break;
883 case added:
884 // method added, see if it is OK
885 new_flags = (jushort) k_new_method->access_flags().get_flags();
886 if ((new_flags & JVM_ACC_PRIVATE) == 0
887 // hack: private should be treated as final, but alas
888 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
889 ) {
890 // new methods must be private
891 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
892 }
893 {
894 u2 num = the_class->next_method_idnum();
895 if (num == ConstMethod::UNSET_IDNUM) {
896 // cannot add any more methods
897 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
898 }
899 u2 new_num = k_new_method->method_idnum();
900 Method* idnum_owner = scratch_class->method_with_idnum(num);
901 if (idnum_owner != NULL) {
902 // There is already a method assigned this idnum -- switch them
903 // Take current and original idnum from the new_method
904 idnum_owner->set_method_idnum(new_num);
905 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
906 }
907 k_new_method->set_method_idnum(num);
908 k_new_method->set_orig_method_idnum(num);
909 if (thread->has_pending_exception()) {
910 return JVMTI_ERROR_OUT_OF_MEMORY;
911 }
912 }
913 log_trace(redefine, class, normalize)
914 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
915 ++ni; // advance to next new method
916 break;
917 case deleted:
918 // method deleted, see if it is OK
919 old_flags = (jushort) k_old_method->access_flags().get_flags();
920 if ((old_flags & JVM_ACC_PRIVATE) == 0
921 // hack: private should be treated as final, but alas
922 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
923 ) {
924 // deleted methods must be private
925 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
926 }
927 log_trace(redefine, class, normalize)
928 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
929 ++oi; // advance to next old method
930 break;
931 default:
932 ShouldNotReachHere();
933 }
934 }
935
936 return JVMTI_ERROR_NONE;
937 }
938
939
940 // Find new constant pool index value for old constant pool index value
941 // by seaching the index map. Returns zero (0) if there is no mapped
942 // value for the old constant pool index.
943 int VM_RedefineClasses::find_new_index(int old_index) {
944 if (_index_map_count == 0) {
945 // map is empty so nothing can be found
946 return 0;
947 }
948
949 if (old_index < 1 || old_index >= _index_map_p->length()) {
950 // The old_index is out of range so it is not mapped. This should
951 // not happen in regular constant pool merging use, but it can
952 // happen if a corrupt annotation is processed.
953 return 0;
954 }
955
956 int value = _index_map_p->at(old_index);
957 if (value == -1) {
958 // the old_index is not mapped
959 return 0;
960 }
961
962 return value;
963 } // end find_new_index()
964
965
966 // Find new bootstrap specifier index value for old bootstrap specifier index
967 // value by seaching the index map. Returns unused index (-1) if there is
968 // no mapped value for the old bootstrap specifier index.
969 int VM_RedefineClasses::find_new_operand_index(int old_index) {
970 if (_operands_index_map_count == 0) {
971 // map is empty so nothing can be found
972 return -1;
973 }
974
975 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
976 // The old_index is out of range so it is not mapped.
977 // This should not happen in regular constant pool merging use.
978 return -1;
979 }
980
981 int value = _operands_index_map_p->at(old_index);
982 if (value == -1) {
983 // the old_index is not mapped
984 return -1;
985 }
986
987 return value;
988 } // end find_new_operand_index()
989
990
991 // Returns true if the current mismatch is due to a resolved/unresolved
992 // class pair. Otherwise, returns false.
993 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
994 int index1, const constantPoolHandle& cp2, int index2) {
995
996 jbyte t1 = cp1->tag_at(index1).value();
997 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
998 return false; // wrong entry type; not our special case
999 }
1000
1001 jbyte t2 = cp2->tag_at(index2).value();
1002 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1003 return false; // wrong entry type; not our special case
1004 }
1005
1006 if (t1 == t2) {
1007 return false; // not a mismatch; not our special case
1008 }
1009
1010 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1011 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1012 if (strcmp(s1, s2) != 0) {
1013 return false; // strings don't match; not our special case
1014 }
1015
1016 return true; // made it through the gauntlet; this is our special case
1017 } // end is_unresolved_class_mismatch()
1018
1019
1020 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1021
1022 // For consistency allocate memory using os::malloc wrapper.
1023 _scratch_classes = (InstanceKlass**)
1024 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1025 if (_scratch_classes == NULL) {
1026 return JVMTI_ERROR_OUT_OF_MEMORY;
1027 }
1028 // Zero initialize the _scratch_classes array.
1029 for (int i = 0; i < _class_count; i++) {
1030 _scratch_classes[i] = NULL;
1031 }
1032
1033 ResourceMark rm(THREAD);
1034
1035 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1036 // state can only be NULL if the current thread is exiting which
1037 // should not happen since we're trying to do a RedefineClasses
1038 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1039 for (int i = 0; i < _class_count; i++) {
1040 // Create HandleMark so that any handles created while loading new class
1041 // versions are deleted. Constant pools are deallocated while merging
1042 // constant pools
1043 HandleMark hm(THREAD);
1044 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1045 Symbol* the_class_sym = the_class->name();
1046
1047 log_debug(redefine, class, load)
1048 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1049 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1050
1051 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1052 _class_defs[i].class_byte_count,
1053 "__VM_RedefineClasses__",
1054 ClassFileStream::verify);
1055
1056 // Parse the stream.
1057 Handle the_class_loader(THREAD, the_class->class_loader());
1058 Handle protection_domain(THREAD, the_class->protection_domain());
1059 // Set redefined class handle in JvmtiThreadState class.
1060 // This redefined class is sent to agent event handler for class file
1061 // load hook event.
1062 state->set_class_being_redefined(the_class, _class_load_kind);
1063
1064 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1065 the_class_sym,
1066 the_class_loader,
1067 protection_domain,
1068 &st,
1069 THREAD);
1070 // Clear class_being_redefined just to be sure.
1071 state->clear_class_being_redefined();
1072
1073 // TODO: if this is retransform, and nothing changed we can skip it
1074
1075 // Need to clean up allocated InstanceKlass if there's an error so assign
1076 // the result here. Caller deallocates all the scratch classes in case of
1077 // an error.
1078 _scratch_classes[i] = scratch_class;
1079
1080 if (HAS_PENDING_EXCEPTION) {
1081 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1082 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1083 CLEAR_PENDING_EXCEPTION;
1084
1085 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1086 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1087 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1088 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1089 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1090 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1091 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1092 // The message will be "XXX (wrong name: YYY)"
1093 return JVMTI_ERROR_NAMES_DONT_MATCH;
1094 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1095 return JVMTI_ERROR_OUT_OF_MEMORY;
1096 } else { // Just in case more exceptions can be thrown..
1097 return JVMTI_ERROR_FAILS_VERIFICATION;
1098 }
1099 }
1100
1101 // Ensure class is linked before redefine
1102 if (!the_class->is_linked()) {
1103 the_class->link_class(THREAD);
1104 if (HAS_PENDING_EXCEPTION) {
1105 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1106 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1107 CLEAR_PENDING_EXCEPTION;
1108 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1109 return JVMTI_ERROR_OUT_OF_MEMORY;
1110 } else {
1111 return JVMTI_ERROR_INTERNAL;
1112 }
1113 }
1114 }
1115
1116 // Do the validity checks in compare_and_normalize_class_versions()
1117 // before verifying the byte codes. By doing these checks first, we
1118 // limit the number of functions that require redirection from
1119 // the_class to scratch_class. In particular, we don't have to
1120 // modify JNI GetSuperclass() and thus won't change its performance.
1121 jvmtiError res = compare_and_normalize_class_versions(the_class,
1122 scratch_class);
1123 if (res != JVMTI_ERROR_NONE) {
1124 return res;
1125 }
1126
1127 // verify what the caller passed us
1128 {
1129 // The bug 6214132 caused the verification to fail.
1130 // Information about the_class and scratch_class is temporarily
1131 // recorded into jvmtiThreadState. This data is used to redirect
1132 // the_class to scratch_class in the JVM_* functions called by the
1133 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1134 // description.
1135 RedefineVerifyMark rvm(the_class, scratch_class, state);
1136 Verifier::verify(
1137 scratch_class, Verifier::ThrowException, true, THREAD);
1138 }
1139
1140 if (HAS_PENDING_EXCEPTION) {
1141 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1142 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1143 CLEAR_PENDING_EXCEPTION;
1144 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1145 return JVMTI_ERROR_OUT_OF_MEMORY;
1146 } else {
1147 // tell the caller the bytecodes are bad
1148 return JVMTI_ERROR_FAILS_VERIFICATION;
1149 }
1150 }
1151
1152 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1153 if (HAS_PENDING_EXCEPTION) {
1154 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1155 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1156 CLEAR_PENDING_EXCEPTION;
1157 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1158 return JVMTI_ERROR_OUT_OF_MEMORY;
1159 } else {
1160 return JVMTI_ERROR_INTERNAL;
1161 }
1162 }
1163
1164 if (VerifyMergedCPBytecodes) {
1165 // verify what we have done during constant pool merging
1166 {
1167 RedefineVerifyMark rvm(the_class, scratch_class, state);
1168 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1169 }
1170
1171 if (HAS_PENDING_EXCEPTION) {
1172 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1173 log_info(redefine, class, load, exceptions)
1174 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1175 CLEAR_PENDING_EXCEPTION;
1176 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1177 return JVMTI_ERROR_OUT_OF_MEMORY;
1178 } else {
1179 // tell the caller that constant pool merging screwed up
1180 return JVMTI_ERROR_INTERNAL;
1181 }
1182 }
1183 }
1184
1185 Rewriter::rewrite(scratch_class, THREAD);
1186 if (!HAS_PENDING_EXCEPTION) {
1187 scratch_class->link_methods(THREAD);
1188 }
1189 if (HAS_PENDING_EXCEPTION) {
1190 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1191 log_info(redefine, class, load, exceptions)
1192 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1193 CLEAR_PENDING_EXCEPTION;
1194 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1195 return JVMTI_ERROR_OUT_OF_MEMORY;
1196 } else {
1197 return JVMTI_ERROR_INTERNAL;
1198 }
1199 }
1200
1201 log_debug(redefine, class, load)
1202 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1203 }
1204
1205 return JVMTI_ERROR_NONE;
1206 }
1207
1208
1209 // Map old_index to new_index as needed. scratch_cp is only needed
1210 // for log calls.
1211 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1212 int old_index, int new_index) {
1213 if (find_new_index(old_index) != 0) {
1214 // old_index is already mapped
1215 return;
1216 }
1217
1218 if (old_index == new_index) {
1219 // no mapping is needed
1220 return;
1221 }
1222
1223 _index_map_p->at_put(old_index, new_index);
1224 _index_map_count++;
1225
1226 log_trace(redefine, class, constantpool)
1227 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1228 } // end map_index()
1229
1230
1231 // Map old_index to new_index as needed.
1232 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1233 if (find_new_operand_index(old_index) != -1) {
1234 // old_index is already mapped
1235 return;
1236 }
1237
1238 if (old_index == new_index) {
1239 // no mapping is needed
1240 return;
1241 }
1242
1243 _operands_index_map_p->at_put(old_index, new_index);
1244 _operands_index_map_count++;
1245
1246 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1247 } // end map_index()
1248
1249
1250 // Merge old_cp and scratch_cp and return the results of the merge via
1251 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1252 // merge_cp_length_p. The entries in old_cp occupy the same locations
1253 // in *merge_cp_p. Also creates a map of indices from entries in
1254 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1255 // entries are only created for entries in scratch_cp that occupy a
1256 // different location in *merged_cp_p.
1257 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1258 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1259 int *merge_cp_length_p, TRAPS) {
1260
1261 if (merge_cp_p == NULL) {
1262 assert(false, "caller must provide scratch constantPool");
1263 return false; // robustness
1264 }
1265 if (merge_cp_length_p == NULL) {
1266 assert(false, "caller must provide scratch CP length");
1267 return false; // robustness
1268 }
1269 // Worst case we need old_cp->length() + scratch_cp()->length(),
1270 // but the caller might be smart so make sure we have at least
1271 // the minimum.
1272 if ((*merge_cp_p)->length() < old_cp->length()) {
1273 assert(false, "merge area too small");
1274 return false; // robustness
1275 }
1276
1277 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1278
1279 {
1280 // Pass 0:
1281 // The old_cp is copied to *merge_cp_p; this means that any code
1282 // using old_cp does not have to change. This work looks like a
1283 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1284 // handle one special case:
1285 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1286 // This will make verification happy.
1287
1288 int old_i; // index into old_cp
1289
1290 // index zero (0) is not used in constantPools
1291 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1292 // leave debugging crumb
1293 jbyte old_tag = old_cp->tag_at(old_i).value();
1294 switch (old_tag) {
1295 case JVM_CONSTANT_Class:
1296 case JVM_CONSTANT_UnresolvedClass:
1297 // revert the copy to JVM_CONSTANT_UnresolvedClass
1298 // May be resolving while calling this so do the same for
1299 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1300 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1301 old_cp->klass_name_index_at(old_i));
1302 break;
1303
1304 case JVM_CONSTANT_Double:
1305 case JVM_CONSTANT_Long:
1306 // just copy the entry to *merge_cp_p, but double and long take
1307 // two constant pool entries
1308 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1309 old_i++;
1310 break;
1311
1312 default:
1313 // just copy the entry to *merge_cp_p
1314 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1315 break;
1316 }
1317 } // end for each old_cp entry
1318
1319 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1320 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1321
1322 // We don't need to sanity check that *merge_cp_length_p is within
1323 // *merge_cp_p bounds since we have the minimum on-entry check above.
1324 (*merge_cp_length_p) = old_i;
1325 }
1326
1327 // merge_cp_len should be the same as old_cp->length() at this point
1328 // so this trace message is really a "warm-and-breathing" message.
1329 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1330
1331 int scratch_i; // index into scratch_cp
1332 {
1333 // Pass 1a:
1334 // Compare scratch_cp entries to the old_cp entries that we have
1335 // already copied to *merge_cp_p. In this pass, we are eliminating
1336 // exact duplicates (matching entry at same index) so we only
1337 // compare entries in the common indice range.
1338 int increment = 1;
1339 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1340 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1341 switch (scratch_cp->tag_at(scratch_i).value()) {
1342 case JVM_CONSTANT_Double:
1343 case JVM_CONSTANT_Long:
1344 // double and long take two constant pool entries
1345 increment = 2;
1346 break;
1347
1348 default:
1349 increment = 1;
1350 break;
1351 }
1352
1353 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1354 scratch_i, CHECK_0);
1355 if (match) {
1356 // found a match at the same index so nothing more to do
1357 continue;
1358 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1359 *merge_cp_p, scratch_i)) {
1360 // The mismatch in compare_entry_to() above is because of a
1361 // resolved versus unresolved class entry at the same index
1362 // with the same string value. Since Pass 0 reverted any
1363 // class entries to unresolved class entries in *merge_cp_p,
1364 // we go with the unresolved class entry.
1365 continue;
1366 }
1367
1368 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1369 CHECK_0);
1370 if (found_i != 0) {
1371 guarantee(found_i != scratch_i,
1372 "compare_entry_to() and find_matching_entry() do not agree");
1373
1374 // Found a matching entry somewhere else in *merge_cp_p so
1375 // just need a mapping entry.
1376 map_index(scratch_cp, scratch_i, found_i);
1377 continue;
1378 }
1379
1380 // The find_matching_entry() call above could fail to find a match
1381 // due to a resolved versus unresolved class or string entry situation
1382 // like we solved above with the is_unresolved_*_mismatch() calls.
1383 // However, we would have to call is_unresolved_*_mismatch() over
1384 // all of *merge_cp_p (potentially) and that doesn't seem to be
1385 // worth the time.
1386
1387 // No match found so we have to append this entry and any unique
1388 // referenced entries to *merge_cp_p.
1389 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1390 CHECK_0);
1391 }
1392 }
1393
1394 log_debug(redefine, class, constantpool)
1395 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1396 *merge_cp_length_p, scratch_i, _index_map_count);
1397
1398 if (scratch_i < scratch_cp->length()) {
1399 // Pass 1b:
1400 // old_cp is smaller than scratch_cp so there are entries in
1401 // scratch_cp that we have not yet processed. We take care of
1402 // those now.
1403 int increment = 1;
1404 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1405 switch (scratch_cp->tag_at(scratch_i).value()) {
1406 case JVM_CONSTANT_Double:
1407 case JVM_CONSTANT_Long:
1408 // double and long take two constant pool entries
1409 increment = 2;
1410 break;
1411
1412 default:
1413 increment = 1;
1414 break;
1415 }
1416
1417 int found_i =
1418 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1419 if (found_i != 0) {
1420 // Found a matching entry somewhere else in *merge_cp_p so
1421 // just need a mapping entry.
1422 map_index(scratch_cp, scratch_i, found_i);
1423 continue;
1424 }
1425
1426 // No match found so we have to append this entry and any unique
1427 // referenced entries to *merge_cp_p.
1428 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1429 CHECK_0);
1430 }
1431
1432 log_debug(redefine, class, constantpool)
1433 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1434 *merge_cp_length_p, scratch_i, _index_map_count);
1435 }
1436 finalize_operands_merge(*merge_cp_p, THREAD);
1437
1438 return true;
1439 } // end merge_constant_pools()
1440
1441
1442 // Scoped object to clean up the constant pool(s) created for merging
1443 class MergeCPCleaner {
1444 ClassLoaderData* _loader_data;
1445 ConstantPool* _cp;
1446 ConstantPool* _scratch_cp;
1447 public:
1448 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1449 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1450 ~MergeCPCleaner() {
1451 _loader_data->add_to_deallocate_list(_cp);
1452 if (_scratch_cp != NULL) {
1453 _loader_data->add_to_deallocate_list(_scratch_cp);
1454 }
1455 }
1456 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1457 };
1458
1459 // Merge constant pools between the_class and scratch_class and
1460 // potentially rewrite bytecodes in scratch_class to use the merged
1461 // constant pool.
1462 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1463 InstanceKlass* the_class, InstanceKlass* scratch_class,
1464 TRAPS) {
1465 // worst case merged constant pool length is old and new combined
1466 int merge_cp_length = the_class->constants()->length()
1467 + scratch_class->constants()->length();
1468
1469 // Constant pools are not easily reused so we allocate a new one
1470 // each time.
1471 // merge_cp is created unsafe for concurrent GC processing. It
1472 // should be marked safe before discarding it. Even though
1473 // garbage, if it crosses a card boundary, it may be scanned
1474 // in order to find the start of the first complete object on the card.
1475 ClassLoaderData* loader_data = the_class->class_loader_data();
1476 ConstantPool* merge_cp_oop =
1477 ConstantPool::allocate(loader_data,
1478 merge_cp_length,
1479 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1480 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1481
1482 HandleMark hm(THREAD); // make sure handles are cleared before
1483 // MergeCPCleaner clears out merge_cp_oop
1484 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1485
1486 // Get constants() from the old class because it could have been rewritten
1487 // while we were at a safepoint allocating a new constant pool.
1488 constantPoolHandle old_cp(THREAD, the_class->constants());
1489 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1490
1491 // If the length changed, the class was redefined out from under us. Return
1492 // an error.
1493 if (merge_cp_length != the_class->constants()->length()
1494 + scratch_class->constants()->length()) {
1495 return JVMTI_ERROR_INTERNAL;
1496 }
1497
1498 // Update the version number of the constant pools (may keep scratch_cp)
1499 merge_cp->increment_and_save_version(old_cp->version());
1500 scratch_cp->increment_and_save_version(old_cp->version());
1501
1502 ResourceMark rm(THREAD);
1503 _index_map_count = 0;
1504 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1505
1506 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1507 _operands_index_map_count = 0;
1508 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1509 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1510
1511 // reference to the cp holder is needed for copy_operands()
1512 merge_cp->set_pool_holder(scratch_class);
1513 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1514 &merge_cp_length, THREAD);
1515 merge_cp->set_pool_holder(NULL);
1516
1517 if (!result) {
1518 // The merge can fail due to memory allocation failure or due
1519 // to robustness checks.
1520 return JVMTI_ERROR_INTERNAL;
1521 }
1522
1523 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1524
1525 if (_index_map_count == 0) {
1526 // there is nothing to map between the new and merged constant pools
1527
1528 if (old_cp->length() == scratch_cp->length()) {
1529 // The old and new constant pools are the same length and the
1530 // index map is empty. This means that the three constant pools
1531 // are equivalent (but not the same). Unfortunately, the new
1532 // constant pool has not gone through link resolution nor have
1533 // the new class bytecodes gone through constant pool cache
1534 // rewriting so we can't use the old constant pool with the new
1535 // class.
1536
1537 // toss the merged constant pool at return
1538 } else if (old_cp->length() < scratch_cp->length()) {
1539 // The old constant pool has fewer entries than the new constant
1540 // pool and the index map is empty. This means the new constant
1541 // pool is a superset of the old constant pool. However, the old
1542 // class bytecodes have already gone through constant pool cache
1543 // rewriting so we can't use the new constant pool with the old
1544 // class.
1545
1546 // toss the merged constant pool at return
1547 } else {
1548 // The old constant pool has more entries than the new constant
1549 // pool and the index map is empty. This means that both the old
1550 // and merged constant pools are supersets of the new constant
1551 // pool.
1552
1553 // Replace the new constant pool with a shrunken copy of the
1554 // merged constant pool
1555 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1556 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1557 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1558 // It can't be cleaned up while there are handles to it.
1559 cp_cleaner.add_scratch_cp(scratch_cp());
1560 }
1561 } else {
1562 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1563 // don't want to loop unless we are tracing
1564 int count = 0;
1565 for (int i = 1; i < _index_map_p->length(); i++) {
1566 int value = _index_map_p->at(i);
1567
1568 if (value != -1) {
1569 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1570 count++;
1571 }
1572 }
1573 }
1574
1575 // We have entries mapped between the new and merged constant pools
1576 // so we have to rewrite some constant pool references.
1577 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1578 return JVMTI_ERROR_INTERNAL;
1579 }
1580
1581 // Replace the new constant pool with a shrunken copy of the
1582 // merged constant pool so now the rewritten bytecodes have
1583 // valid references; the previous new constant pool will get
1584 // GCed.
1585 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1586 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1587 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1588 // It can't be cleaned up while there are handles to it.
1589 cp_cleaner.add_scratch_cp(scratch_cp());
1590 }
1591
1592 return JVMTI_ERROR_NONE;
1593 } // end merge_cp_and_rewrite()
1594
1595
1596 // Rewrite constant pool references in klass scratch_class.
1597 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1598 TRAPS) {
1599
1600 // rewrite constant pool references in the methods:
1601 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1602 // propagate failure back to caller
1603 return false;
1604 }
1605
1606 // rewrite constant pool references in the class_annotations:
1607 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1608 // propagate failure back to caller
1609 return false;
1610 }
1611
1612 // rewrite constant pool references in the fields_annotations:
1613 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1614 // propagate failure back to caller
1615 return false;
1616 }
1617
1618 // rewrite constant pool references in the methods_annotations:
1619 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1620 // propagate failure back to caller
1621 return false;
1622 }
1623
1624 // rewrite constant pool references in the methods_parameter_annotations:
1625 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1626 THREAD)) {
1627 // propagate failure back to caller
1628 return false;
1629 }
1630
1631 // rewrite constant pool references in the methods_default_annotations:
1632 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1633 THREAD)) {
1634 // propagate failure back to caller
1635 return false;
1636 }
1637
1638 // rewrite constant pool references in the class_type_annotations:
1639 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1640 // propagate failure back to caller
1641 return false;
1642 }
1643
1644 // rewrite constant pool references in the fields_type_annotations:
1645 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1646 // propagate failure back to caller
1647 return false;
1648 }
1649
1650 // rewrite constant pool references in the methods_type_annotations:
1651 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1652 // propagate failure back to caller
1653 return false;
1654 }
1655
1656 // There can be type annotations in the Code part of a method_info attribute.
1657 // These annotations are not accessible, even by reflection.
1658 // Currently they are not even parsed by the ClassFileParser.
1659 // If runtime access is added they will also need to be rewritten.
1660
1661 // rewrite source file name index:
1662 u2 source_file_name_idx = scratch_class->source_file_name_index();
1663 if (source_file_name_idx != 0) {
1664 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1665 if (new_source_file_name_idx != 0) {
1666 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1667 }
1668 }
1669
1670 // rewrite class generic signature index:
1671 u2 generic_signature_index = scratch_class->generic_signature_index();
1672 if (generic_signature_index != 0) {
1673 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1674 if (new_generic_signature_index != 0) {
1675 scratch_class->set_generic_signature_index(new_generic_signature_index);
1676 }
1677 }
1678
1679 return true;
1680 } // end rewrite_cp_refs()
1681
1682 // Rewrite constant pool references in the methods.
1683 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1684 InstanceKlass* scratch_class, TRAPS) {
1685
1686 Array<Method*>* methods = scratch_class->methods();
1687
1688 if (methods == NULL || methods->length() == 0) {
1689 // no methods so nothing to do
1690 return true;
1691 }
1692
1693 // rewrite constant pool references in the methods:
1694 for (int i = methods->length() - 1; i >= 0; i--) {
1695 methodHandle method(THREAD, methods->at(i));
1696 methodHandle new_method;
1697 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1698 if (!new_method.is_null()) {
1699 // the method has been replaced so save the new method version
1700 // even in the case of an exception. original method is on the
1701 // deallocation list.
1702 methods->at_put(i, new_method());
1703 }
1704 if (HAS_PENDING_EXCEPTION) {
1705 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1706 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1707 // Need to clear pending exception here as the super caller sets
1708 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1709 CLEAR_PENDING_EXCEPTION;
1710 return false;
1711 }
1712 }
1713
1714 return true;
1715 }
1716
1717
1718 // Rewrite constant pool references in the specific method. This code
1719 // was adapted from Rewriter::rewrite_method().
1720 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1721 methodHandle *new_method_p, TRAPS) {
1722
1723 *new_method_p = methodHandle(); // default is no new method
1724
1725 // We cache a pointer to the bytecodes here in code_base. If GC
1726 // moves the Method*, then the bytecodes will also move which
1727 // will likely cause a crash. We create a NoSafepointVerifier
1728 // object to detect whether we pass a possible safepoint in this
1729 // code block.
1730 NoSafepointVerifier nsv;
1731
1732 // Bytecodes and their length
1733 address code_base = method->code_base();
1734 int code_length = method->code_size();
1735
1736 int bc_length;
1737 for (int bci = 0; bci < code_length; bci += bc_length) {
1738 address bcp = code_base + bci;
1739 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1740
1741 bc_length = Bytecodes::length_for(c);
1742 if (bc_length == 0) {
1743 // More complicated bytecodes report a length of zero so
1744 // we have to try again a slightly different way.
1745 bc_length = Bytecodes::length_at(method(), bcp);
1746 }
1747
1748 assert(bc_length != 0, "impossible bytecode length");
1749
1750 switch (c) {
1751 case Bytecodes::_ldc:
1752 {
1753 int cp_index = *(bcp + 1);
1754 int new_index = find_new_index(cp_index);
1755
1756 if (StressLdcRewrite && new_index == 0) {
1757 // If we are stressing ldc -> ldc_w rewriting, then we
1758 // always need a new_index value.
1759 new_index = cp_index;
1760 }
1761 if (new_index != 0) {
1762 // the original index is mapped so we have more work to do
1763 if (!StressLdcRewrite && new_index <= max_jubyte) {
1764 // The new value can still use ldc instead of ldc_w
1765 // unless we are trying to stress ldc -> ldc_w rewriting
1766 log_trace(redefine, class, constantpool)
1767 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1768 *(bcp + 1) = new_index;
1769 } else {
1770 log_trace(redefine, class, constantpool)
1771 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1772 // the new value needs ldc_w instead of ldc
1773 u_char inst_buffer[4]; // max instruction size is 4 bytes
1774 bcp = (address)inst_buffer;
1775 // construct new instruction sequence
1776 *bcp = Bytecodes::_ldc_w;
1777 bcp++;
1778 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1779 // See comment below for difference between put_Java_u2()
1780 // and put_native_u2().
1781 Bytes::put_Java_u2(bcp, new_index);
1782
1783 Relocator rc(method, NULL /* no RelocatorListener needed */);
1784 methodHandle m;
1785 {
1786 PauseNoSafepointVerifier pnsv(&nsv);
1787
1788 // ldc is 2 bytes and ldc_w is 3 bytes
1789 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1790 }
1791
1792 // return the new method so that the caller can update
1793 // the containing class
1794 *new_method_p = method = m;
1795 // switch our bytecode processing loop from the old method
1796 // to the new method
1797 code_base = method->code_base();
1798 code_length = method->code_size();
1799 bcp = code_base + bci;
1800 c = (Bytecodes::Code)(*bcp);
1801 bc_length = Bytecodes::length_for(c);
1802 assert(bc_length != 0, "sanity check");
1803 } // end we need ldc_w instead of ldc
1804 } // end if there is a mapped index
1805 } break;
1806
1807 // these bytecodes have a two-byte constant pool index
1808 case Bytecodes::_anewarray : // fall through
1809 case Bytecodes::_checkcast : // fall through
1810 case Bytecodes::_getfield : // fall through
1811 case Bytecodes::_getstatic : // fall through
1812 case Bytecodes::_instanceof : // fall through
1813 case Bytecodes::_invokedynamic : // fall through
1814 case Bytecodes::_invokeinterface: // fall through
1815 case Bytecodes::_invokespecial : // fall through
1816 case Bytecodes::_invokestatic : // fall through
1817 case Bytecodes::_invokevirtual : // fall through
1818 case Bytecodes::_ldc_w : // fall through
1819 case Bytecodes::_ldc2_w : // fall through
1820 case Bytecodes::_multianewarray : // fall through
1821 case Bytecodes::_new : // fall through
1822 case Bytecodes::_putfield : // fall through
1823 case Bytecodes::_putstatic :
1824 {
1825 address p = bcp + 1;
1826 int cp_index = Bytes::get_Java_u2(p);
1827 int new_index = find_new_index(cp_index);
1828 if (new_index != 0) {
1829 // the original index is mapped so update w/ new value
1830 log_trace(redefine, class, constantpool)
1831 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1832 // Rewriter::rewrite_method() uses put_native_u2() in this
1833 // situation because it is reusing the constant pool index
1834 // location for a native index into the ConstantPoolCache.
1835 // Since we are updating the constant pool index prior to
1836 // verification and ConstantPoolCache initialization, we
1837 // need to keep the new index in Java byte order.
1838 Bytes::put_Java_u2(p, new_index);
1839 }
1840 } break;
1841 default:
1842 break;
1843 }
1844 } // end for each bytecode
1845
1846 // We also need to rewrite the parameter name indexes, if there is
1847 // method parameter data present
1848 if(method->has_method_parameters()) {
1849 const int len = method->method_parameters_length();
1850 MethodParametersElement* elem = method->method_parameters_start();
1851
1852 for (int i = 0; i < len; i++) {
1853 const u2 cp_index = elem[i].name_cp_index;
1854 const u2 new_cp_index = find_new_index(cp_index);
1855 if (new_cp_index != 0) {
1856 elem[i].name_cp_index = new_cp_index;
1857 }
1858 }
1859 }
1860 } // end rewrite_cp_refs_in_method()
1861
1862
1863 // Rewrite constant pool references in the class_annotations field.
1864 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1865 InstanceKlass* scratch_class, TRAPS) {
1866
1867 AnnotationArray* class_annotations = scratch_class->class_annotations();
1868 if (class_annotations == NULL || class_annotations->length() == 0) {
1869 // no class_annotations so nothing to do
1870 return true;
1871 }
1872
1873 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1874
1875 int byte_i = 0; // byte index into class_annotations
1876 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1877 THREAD);
1878 }
1879
1880
1881 // Rewrite constant pool references in an annotations typeArray. This
1882 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1883 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1884 //
1885 // annotations_typeArray {
1886 // u2 num_annotations;
1887 // annotation annotations[num_annotations];
1888 // }
1889 //
1890 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1891 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1892
1893 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1894 // not enough room for num_annotations field
1895 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1896 return false;
1897 }
1898
1899 u2 num_annotations = Bytes::get_Java_u2((address)
1900 annotations_typeArray->adr_at(byte_i_ref));
1901 byte_i_ref += 2;
1902
1903 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1904
1905 int calc_num_annotations = 0;
1906 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1907 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1908 byte_i_ref, THREAD)) {
1909 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1910 // propagate failure back to caller
1911 return false;
1912 }
1913 }
1914 assert(num_annotations == calc_num_annotations, "sanity check");
1915
1916 return true;
1917 } // end rewrite_cp_refs_in_annotations_typeArray()
1918
1919
1920 // Rewrite constant pool references in the annotation struct portion of
1921 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1922 // the 2nd-edition of the VM spec:
1923 //
1924 // struct annotation {
1925 // u2 type_index;
1926 // u2 num_element_value_pairs;
1927 // {
1928 // u2 element_name_index;
1929 // element_value value;
1930 // } element_value_pairs[num_element_value_pairs];
1931 // }
1932 //
1933 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1934 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1935 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1936 // not enough room for smallest annotation_struct
1937 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1938 return false;
1939 }
1940
1941 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1942 byte_i_ref, "type_index", THREAD);
1943
1944 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1945 annotations_typeArray->adr_at(byte_i_ref));
1946 byte_i_ref += 2;
1947
1948 log_debug(redefine, class, annotation)
1949 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1950
1951 int calc_num_element_value_pairs = 0;
1952 for (; calc_num_element_value_pairs < num_element_value_pairs;
1953 calc_num_element_value_pairs++) {
1954 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1955 // not enough room for another element_name_index, let alone
1956 // the rest of another component
1957 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1958 return false;
1959 }
1960
1961 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1962 annotations_typeArray, byte_i_ref,
1963 "element_name_index", THREAD);
1964
1965 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1966
1967 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1968 byte_i_ref, THREAD)) {
1969 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1970 // propagate failure back to caller
1971 return false;
1972 }
1973 } // end for each component
1974 assert(num_element_value_pairs == calc_num_element_value_pairs,
1975 "sanity check");
1976
1977 return true;
1978 } // end rewrite_cp_refs_in_annotation_struct()
1979
1980
1981 // Rewrite a constant pool reference at the current position in
1982 // annotations_typeArray if needed. Returns the original constant
1983 // pool reference if a rewrite was not needed or the new constant
1984 // pool reference if a rewrite was needed.
1985 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1986 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1987 const char * trace_mesg, TRAPS) {
1988
1989 address cp_index_addr = (address)
1990 annotations_typeArray->adr_at(byte_i_ref);
1991 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1992 u2 new_cp_index = find_new_index(old_cp_index);
1993 if (new_cp_index != 0) {
1994 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1995 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1996 old_cp_index = new_cp_index;
1997 }
1998 byte_i_ref += 2;
1999 return old_cp_index;
2000 }
2001
2002
2003 // Rewrite constant pool references in the element_value portion of an
2004 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2005 // the 2nd-edition of the VM spec:
2006 //
2007 // struct element_value {
2008 // u1 tag;
2009 // union {
2010 // u2 const_value_index;
2011 // {
2012 // u2 type_name_index;
2013 // u2 const_name_index;
2014 // } enum_const_value;
2015 // u2 class_info_index;
2016 // annotation annotation_value;
2017 // struct {
2018 // u2 num_values;
2019 // element_value values[num_values];
2020 // } array_value;
2021 // } value;
2022 // }
2023 //
2024 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2025 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2026
2027 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2028 // not enough room for a tag let alone the rest of an element_value
2029 log_debug(redefine, class, annotation)("length() is too small for a tag");
2030 return false;
2031 }
2032
2033 u1 tag = annotations_typeArray->at(byte_i_ref);
2034 byte_i_ref++;
2035 log_debug(redefine, class, annotation)("tag='%c'", tag);
2036
2037 switch (tag) {
2038 // These BaseType tag values are from Table 4.2 in VM spec:
2039 case 'B': // byte
2040 case 'C': // char
2041 case 'D': // double
2042 case 'F': // float
2043 case 'I': // int
2044 case 'J': // long
2045 case 'S': // short
2046 case 'Z': // boolean
2047
2048 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2049 // the VM spec:
2050 case 's':
2051 {
2052 // For the above tag values (including the BaseType values),
2053 // value.const_value_index is right union field.
2054
2055 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2056 // not enough room for a const_value_index
2057 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2058 return false;
2059 }
2060
2061 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2062 annotations_typeArray, byte_i_ref,
2063 "const_value_index", THREAD);
2064
2065 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2066 } break;
2067
2068 case 'e':
2069 {
2070 // for the above tag value, value.enum_const_value is right union field
2071
2072 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2073 // not enough room for a enum_const_value
2074 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2075 return false;
2076 }
2077
2078 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2079 annotations_typeArray, byte_i_ref,
2080 "type_name_index", THREAD);
2081
2082 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2083 annotations_typeArray, byte_i_ref,
2084 "const_name_index", THREAD);
2085
2086 log_debug(redefine, class, annotation)
2087 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2088 } break;
2089
2090 case 'c':
2091 {
2092 // for the above tag value, value.class_info_index is right union field
2093
2094 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2095 // not enough room for a class_info_index
2096 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2097 return false;
2098 }
2099
2100 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2101 annotations_typeArray, byte_i_ref,
2102 "class_info_index", THREAD);
2103
2104 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2105 } break;
2106
2107 case '@':
2108 // For the above tag value, value.attr_value is the right union
2109 // field. This is a nested annotation.
2110 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2111 byte_i_ref, THREAD)) {
2112 // propagate failure back to caller
2113 return false;
2114 }
2115 break;
2116
2117 case '[':
2118 {
2119 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2120 // not enough room for a num_values field
2121 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2122 return false;
2123 }
2124
2125 // For the above tag value, value.array_value is the right union
2126 // field. This is an array of nested element_value.
2127 u2 num_values = Bytes::get_Java_u2((address)
2128 annotations_typeArray->adr_at(byte_i_ref));
2129 byte_i_ref += 2;
2130 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2131
2132 int calc_num_values = 0;
2133 for (; calc_num_values < num_values; calc_num_values++) {
2134 if (!rewrite_cp_refs_in_element_value(
2135 annotations_typeArray, byte_i_ref, THREAD)) {
2136 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2137 // propagate failure back to caller
2138 return false;
2139 }
2140 }
2141 assert(num_values == calc_num_values, "sanity check");
2142 } break;
2143
2144 default:
2145 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2146 return false;
2147 } // end decode tag field
2148
2149 return true;
2150 } // end rewrite_cp_refs_in_element_value()
2151
2152
2153 // Rewrite constant pool references in a fields_annotations field.
2154 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2155 InstanceKlass* scratch_class, TRAPS) {
2156
2157 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2158
2159 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2160 // no fields_annotations so nothing to do
2161 return true;
2162 }
2163
2164 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2165
2166 for (int i = 0; i < fields_annotations->length(); i++) {
2167 AnnotationArray* field_annotations = fields_annotations->at(i);
2168 if (field_annotations == NULL || field_annotations->length() == 0) {
2169 // this field does not have any annotations so skip it
2170 continue;
2171 }
2172
2173 int byte_i = 0; // byte index into field_annotations
2174 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2175 THREAD)) {
2176 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2177 // propagate failure back to caller
2178 return false;
2179 }
2180 }
2181
2182 return true;
2183 } // end rewrite_cp_refs_in_fields_annotations()
2184
2185
2186 // Rewrite constant pool references in a methods_annotations field.
2187 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2188 InstanceKlass* scratch_class, TRAPS) {
2189
2190 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2191 Method* m = scratch_class->methods()->at(i);
2192 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2193
2194 if (method_annotations == NULL || method_annotations->length() == 0) {
2195 // this method does not have any annotations so skip it
2196 continue;
2197 }
2198
2199 int byte_i = 0; // byte index into method_annotations
2200 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2201 THREAD)) {
2202 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2203 // propagate failure back to caller
2204 return false;
2205 }
2206 }
2207
2208 return true;
2209 } // end rewrite_cp_refs_in_methods_annotations()
2210
2211
2212 // Rewrite constant pool references in a methods_parameter_annotations
2213 // field. This "structure" is adapted from the
2214 // RuntimeVisibleParameterAnnotations_attribute described in section
2215 // 4.8.17 of the 2nd-edition of the VM spec:
2216 //
2217 // methods_parameter_annotations_typeArray {
2218 // u1 num_parameters;
2219 // {
2220 // u2 num_annotations;
2221 // annotation annotations[num_annotations];
2222 // } parameter_annotations[num_parameters];
2223 // }
2224 //
2225 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2226 InstanceKlass* scratch_class, TRAPS) {
2227
2228 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2229 Method* m = scratch_class->methods()->at(i);
2230 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2231 if (method_parameter_annotations == NULL
2232 || method_parameter_annotations->length() == 0) {
2233 // this method does not have any parameter annotations so skip it
2234 continue;
2235 }
2236
2237 if (method_parameter_annotations->length() < 1) {
2238 // not enough room for a num_parameters field
2239 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2240 return false;
2241 }
2242
2243 int byte_i = 0; // byte index into method_parameter_annotations
2244
2245 u1 num_parameters = method_parameter_annotations->at(byte_i);
2246 byte_i++;
2247
2248 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2249
2250 int calc_num_parameters = 0;
2251 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2252 if (!rewrite_cp_refs_in_annotations_typeArray(
2253 method_parameter_annotations, byte_i, THREAD)) {
2254 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2255 // propagate failure back to caller
2256 return false;
2257 }
2258 }
2259 assert(num_parameters == calc_num_parameters, "sanity check");
2260 }
2261
2262 return true;
2263 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2264
2265
2266 // Rewrite constant pool references in a methods_default_annotations
2267 // field. This "structure" is adapted from the AnnotationDefault_attribute
2268 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2269 //
2270 // methods_default_annotations_typeArray {
2271 // element_value default_value;
2272 // }
2273 //
2274 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2275 InstanceKlass* scratch_class, TRAPS) {
2276
2277 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2278 Method* m = scratch_class->methods()->at(i);
2279 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2280 if (method_default_annotations == NULL
2281 || method_default_annotations->length() == 0) {
2282 // this method does not have any default annotations so skip it
2283 continue;
2284 }
2285
2286 int byte_i = 0; // byte index into method_default_annotations
2287
2288 if (!rewrite_cp_refs_in_element_value(
2289 method_default_annotations, byte_i, THREAD)) {
2290 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2291 // propagate failure back to caller
2292 return false;
2293 }
2294 }
2295
2296 return true;
2297 } // end rewrite_cp_refs_in_methods_default_annotations()
2298
2299
2300 // Rewrite constant pool references in a class_type_annotations field.
2301 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2302 InstanceKlass* scratch_class, TRAPS) {
2303
2304 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2305 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2306 // no class_type_annotations so nothing to do
2307 return true;
2308 }
2309
2310 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2311
2312 int byte_i = 0; // byte index into class_type_annotations
2313 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2314 byte_i, "ClassFile", THREAD);
2315 } // end rewrite_cp_refs_in_class_type_annotations()
2316
2317
2318 // Rewrite constant pool references in a fields_type_annotations field.
2319 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2320 InstanceKlass* scratch_class, TRAPS) {
2321
2322 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2323 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2324 // no fields_type_annotations so nothing to do
2325 return true;
2326 }
2327
2328 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2329
2330 for (int i = 0; i < fields_type_annotations->length(); i++) {
2331 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2332 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2333 // this field does not have any annotations so skip it
2334 continue;
2335 }
2336
2337 int byte_i = 0; // byte index into field_type_annotations
2338 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2339 byte_i, "field_info", THREAD)) {
2340 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2341 // propagate failure back to caller
2342 return false;
2343 }
2344 }
2345
2346 return true;
2347 } // end rewrite_cp_refs_in_fields_type_annotations()
2348
2349
2350 // Rewrite constant pool references in a methods_type_annotations field.
2351 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2352 InstanceKlass* scratch_class, TRAPS) {
2353
2354 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2355 Method* m = scratch_class->methods()->at(i);
2356 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2357
2358 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2359 // this method does not have any annotations so skip it
2360 continue;
2361 }
2362
2363 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2364
2365 int byte_i = 0; // byte index into method_type_annotations
2366 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2367 byte_i, "method_info", THREAD)) {
2368 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2369 // propagate failure back to caller
2370 return false;
2371 }
2372 }
2373
2374 return true;
2375 } // end rewrite_cp_refs_in_methods_type_annotations()
2376
2377
2378 // Rewrite constant pool references in a type_annotations
2379 // field. This "structure" is adapted from the
2380 // RuntimeVisibleTypeAnnotations_attribute described in
2381 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2382 //
2383 // type_annotations_typeArray {
2384 // u2 num_annotations;
2385 // type_annotation annotations[num_annotations];
2386 // }
2387 //
2388 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2389 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2390 const char * location_mesg, TRAPS) {
2391
2392 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2393 // not enough room for num_annotations field
2394 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2395 return false;
2396 }
2397
2398 u2 num_annotations = Bytes::get_Java_u2((address)
2399 type_annotations_typeArray->adr_at(byte_i_ref));
2400 byte_i_ref += 2;
2401
2402 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2403
2404 int calc_num_annotations = 0;
2405 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2406 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2407 byte_i_ref, location_mesg, THREAD)) {
2408 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2409 // propagate failure back to caller
2410 return false;
2411 }
2412 }
2413 assert(num_annotations == calc_num_annotations, "sanity check");
2414
2415 if (byte_i_ref != type_annotations_typeArray->length()) {
2416 log_debug(redefine, class, annotation)
2417 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2418 byte_i_ref, type_annotations_typeArray->length());
2419 return false;
2420 }
2421
2422 return true;
2423 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2424
2425
2426 // Rewrite constant pool references in a type_annotation
2427 // field. This "structure" is adapted from the
2428 // RuntimeVisibleTypeAnnotations_attribute described in
2429 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2430 //
2431 // type_annotation {
2432 // u1 target_type;
2433 // union {
2434 // type_parameter_target;
2435 // supertype_target;
2436 // type_parameter_bound_target;
2437 // empty_target;
2438 // method_formal_parameter_target;
2439 // throws_target;
2440 // localvar_target;
2441 // catch_target;
2442 // offset_target;
2443 // type_argument_target;
2444 // } target_info;
2445 // type_path target_path;
2446 // annotation anno;
2447 // }
2448 //
2449 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2450 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2451 const char * location_mesg, TRAPS) {
2452
2453 if (!skip_type_annotation_target(type_annotations_typeArray,
2454 byte_i_ref, location_mesg, THREAD)) {
2455 return false;
2456 }
2457
2458 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2459 byte_i_ref, THREAD)) {
2460 return false;
2461 }
2462
2463 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2464 byte_i_ref, THREAD)) {
2465 return false;
2466 }
2467
2468 return true;
2469 } // end rewrite_cp_refs_in_type_annotation_struct()
2470
2471
2472 // Read, verify and skip over the target_type and target_info part
2473 // so that rewriting can continue in the later parts of the struct.
2474 //
2475 // u1 target_type;
2476 // union {
2477 // type_parameter_target;
2478 // supertype_target;
2479 // type_parameter_bound_target;
2480 // empty_target;
2481 // method_formal_parameter_target;
2482 // throws_target;
2483 // localvar_target;
2484 // catch_target;
2485 // offset_target;
2486 // type_argument_target;
2487 // } target_info;
2488 //
2489 bool VM_RedefineClasses::skip_type_annotation_target(
2490 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2491 const char * location_mesg, TRAPS) {
2492
2493 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2494 // not enough room for a target_type let alone the rest of a type_annotation
2495 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2496 return false;
2497 }
2498
2499 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2500 byte_i_ref += 1;
2501 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2502 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2503
2504 // Skip over target_info
2505 switch (target_type) {
2506 case 0x00:
2507 // kind: type parameter declaration of generic class or interface
2508 // location: ClassFile
2509 case 0x01:
2510 // kind: type parameter declaration of generic method or constructor
2511 // location: method_info
2512
2513 {
2514 // struct:
2515 // type_parameter_target {
2516 // u1 type_parameter_index;
2517 // }
2518 //
2519 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2520 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2521 return false;
2522 }
2523
2524 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2525 byte_i_ref += 1;
2526
2527 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2528 } break;
2529
2530 case 0x10:
2531 // kind: type in extends clause of class or interface declaration
2532 // (including the direct superclass of an anonymous class declaration),
2533 // or in implements clause of interface declaration
2534 // location: ClassFile
2535
2536 {
2537 // struct:
2538 // supertype_target {
2539 // u2 supertype_index;
2540 // }
2541 //
2542 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2543 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2544 return false;
2545 }
2546
2547 u2 supertype_index = Bytes::get_Java_u2((address)
2548 type_annotations_typeArray->adr_at(byte_i_ref));
2549 byte_i_ref += 2;
2550
2551 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2552 } break;
2553
2554 case 0x11:
2555 // kind: type in bound of type parameter declaration of generic class or interface
2556 // location: ClassFile
2557 case 0x12:
2558 // kind: type in bound of type parameter declaration of generic method or constructor
2559 // location: method_info
2560
2561 {
2562 // struct:
2563 // type_parameter_bound_target {
2564 // u1 type_parameter_index;
2565 // u1 bound_index;
2566 // }
2567 //
2568 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2569 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2570 return false;
2571 }
2572
2573 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2574 byte_i_ref += 1;
2575 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2576 byte_i_ref += 1;
2577
2578 log_debug(redefine, class, annotation)
2579 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2580 } break;
2581
2582 case 0x13:
2583 // kind: type in field declaration
2584 // location: field_info
2585 case 0x14:
2586 // kind: return type of method, or type of newly constructed object
2587 // location: method_info
2588 case 0x15:
2589 // kind: receiver type of method or constructor
2590 // location: method_info
2591
2592 {
2593 // struct:
2594 // empty_target {
2595 // }
2596 //
2597 log_debug(redefine, class, annotation)("empty_target");
2598 } break;
2599
2600 case 0x16:
2601 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2602 // location: method_info
2603
2604 {
2605 // struct:
2606 // formal_parameter_target {
2607 // u1 formal_parameter_index;
2608 // }
2609 //
2610 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2611 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2612 return false;
2613 }
2614
2615 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2616 byte_i_ref += 1;
2617
2618 log_debug(redefine, class, annotation)
2619 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2620 } break;
2621
2622 case 0x17:
2623 // kind: type in throws clause of method or constructor
2624 // location: method_info
2625
2626 {
2627 // struct:
2628 // throws_target {
2629 // u2 throws_type_index
2630 // }
2631 //
2632 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2633 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2634 return false;
2635 }
2636
2637 u2 throws_type_index = Bytes::get_Java_u2((address)
2638 type_annotations_typeArray->adr_at(byte_i_ref));
2639 byte_i_ref += 2;
2640
2641 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2642 } break;
2643
2644 case 0x40:
2645 // kind: type in local variable declaration
2646 // location: Code
2647 case 0x41:
2648 // kind: type in resource variable declaration
2649 // location: Code
2650
2651 {
2652 // struct:
2653 // localvar_target {
2654 // u2 table_length;
2655 // struct {
2656 // u2 start_pc;
2657 // u2 length;
2658 // u2 index;
2659 // } table[table_length];
2660 // }
2661 //
2662 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2663 // not enough room for a table_length let alone the rest of a localvar_target
2664 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2665 return false;
2666 }
2667
2668 u2 table_length = Bytes::get_Java_u2((address)
2669 type_annotations_typeArray->adr_at(byte_i_ref));
2670 byte_i_ref += 2;
2671
2672 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2673
2674 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2675 int table_size = table_length * table_struct_size;
2676
2677 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2678 // not enough room for a table
2679 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2680 return false;
2681 }
2682
2683 // Skip over table
2684 byte_i_ref += table_size;
2685 } break;
2686
2687 case 0x42:
2688 // kind: type in exception parameter declaration
2689 // location: Code
2690
2691 {
2692 // struct:
2693 // catch_target {
2694 // u2 exception_table_index;
2695 // }
2696 //
2697 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2698 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2699 return false;
2700 }
2701
2702 u2 exception_table_index = Bytes::get_Java_u2((address)
2703 type_annotations_typeArray->adr_at(byte_i_ref));
2704 byte_i_ref += 2;
2705
2706 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2707 } break;
2708
2709 case 0x43:
2710 // kind: type in instanceof expression
2711 // location: Code
2712 case 0x44:
2713 // kind: type in new expression
2714 // location: Code
2715 case 0x45:
2716 // kind: type in method reference expression using ::new
2717 // location: Code
2718 case 0x46:
2719 // kind: type in method reference expression using ::Identifier
2720 // location: Code
2721
2722 {
2723 // struct:
2724 // offset_target {
2725 // u2 offset;
2726 // }
2727 //
2728 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2729 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2730 return false;
2731 }
2732
2733 u2 offset = Bytes::get_Java_u2((address)
2734 type_annotations_typeArray->adr_at(byte_i_ref));
2735 byte_i_ref += 2;
2736
2737 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2738 } break;
2739
2740 case 0x47:
2741 // kind: type in cast expression
2742 // location: Code
2743 case 0x48:
2744 // kind: type argument for generic constructor in new expression or
2745 // explicit constructor invocation statement
2746 // location: Code
2747 case 0x49:
2748 // kind: type argument for generic method in method invocation expression
2749 // location: Code
2750 case 0x4A:
2751 // kind: type argument for generic constructor in method reference expression using ::new
2752 // location: Code
2753 case 0x4B:
2754 // kind: type argument for generic method in method reference expression using ::Identifier
2755 // location: Code
2756
2757 {
2758 // struct:
2759 // type_argument_target {
2760 // u2 offset;
2761 // u1 type_argument_index;
2762 // }
2763 //
2764 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2765 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2766 return false;
2767 }
2768
2769 u2 offset = Bytes::get_Java_u2((address)
2770 type_annotations_typeArray->adr_at(byte_i_ref));
2771 byte_i_ref += 2;
2772 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2773 byte_i_ref += 1;
2774
2775 log_debug(redefine, class, annotation)
2776 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2777 } break;
2778
2779 default:
2780 log_debug(redefine, class, annotation)("unknown target_type");
2781 #ifdef ASSERT
2782 ShouldNotReachHere();
2783 #endif
2784 return false;
2785 }
2786
2787 return true;
2788 } // end skip_type_annotation_target()
2789
2790
2791 // Read, verify and skip over the type_path part so that rewriting
2792 // can continue in the later parts of the struct.
2793 //
2794 // type_path {
2795 // u1 path_length;
2796 // {
2797 // u1 type_path_kind;
2798 // u1 type_argument_index;
2799 // } path[path_length];
2800 // }
2801 //
2802 bool VM_RedefineClasses::skip_type_annotation_type_path(
2803 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2804
2805 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2806 // not enough room for a path_length let alone the rest of the type_path
2807 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2808 return false;
2809 }
2810
2811 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2812 byte_i_ref += 1;
2813
2814 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2815
2816 int calc_path_length = 0;
2817 for (; calc_path_length < path_length; calc_path_length++) {
2818 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2819 // not enough room for a path
2820 log_debug(redefine, class, annotation)
2821 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2822 return false;
2823 }
2824
2825 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2826 byte_i_ref += 1;
2827 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2828 byte_i_ref += 1;
2829
2830 log_debug(redefine, class, annotation)
2831 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2832 calc_path_length, type_path_kind, type_argument_index);
2833
2834 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2835 // not enough room for a path
2836 log_debug(redefine, class, annotation)("inconsistent type_path values");
2837 return false;
2838 }
2839 }
2840 assert(path_length == calc_path_length, "sanity check");
2841
2842 return true;
2843 } // end skip_type_annotation_type_path()
2844
2845
2846 // Rewrite constant pool references in the method's stackmap table.
2847 // These "structures" are adapted from the StackMapTable_attribute that
2848 // is described in section 4.8.4 of the 6.0 version of the VM spec
2849 // (dated 2005.10.26):
2850 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2851 //
2852 // stack_map {
2853 // u2 number_of_entries;
2854 // stack_map_frame entries[number_of_entries];
2855 // }
2856 //
2857 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2858 const methodHandle& method, TRAPS) {
2859
2860 if (!method->has_stackmap_table()) {
2861 return;
2862 }
2863
2864 AnnotationArray* stackmap_data = method->stackmap_data();
2865 address stackmap_p = (address)stackmap_data->adr_at(0);
2866 address stackmap_end = stackmap_p + stackmap_data->length();
2867
2868 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2869 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2870 stackmap_p += 2;
2871
2872 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2873
2874 // walk through each stack_map_frame
2875 u2 calc_number_of_entries = 0;
2876 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2877 // The stack_map_frame structure is a u1 frame_type followed by
2878 // 0 or more bytes of data:
2879 //
2880 // union stack_map_frame {
2881 // same_frame;
2882 // same_locals_1_stack_item_frame;
2883 // same_locals_1_stack_item_frame_extended;
2884 // chop_frame;
2885 // same_frame_extended;
2886 // append_frame;
2887 // full_frame;
2888 // }
2889
2890 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2891 u1 frame_type = *stackmap_p;
2892 stackmap_p++;
2893
2894 // same_frame {
2895 // u1 frame_type = SAME; /* 0-63 */
2896 // }
2897 if (frame_type <= 63) {
2898 // nothing more to do for same_frame
2899 }
2900
2901 // same_locals_1_stack_item_frame {
2902 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2903 // verification_type_info stack[1];
2904 // }
2905 else if (frame_type >= 64 && frame_type <= 127) {
2906 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2907 calc_number_of_entries, frame_type, THREAD);
2908 }
2909
2910 // reserved for future use
2911 else if (frame_type >= 128 && frame_type <= 246) {
2912 // nothing more to do for reserved frame_types
2913 }
2914
2915 // same_locals_1_stack_item_frame_extended {
2916 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2917 // u2 offset_delta;
2918 // verification_type_info stack[1];
2919 // }
2920 else if (frame_type == 247) {
2921 stackmap_p += 2;
2922 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2923 calc_number_of_entries, frame_type, THREAD);
2924 }
2925
2926 // chop_frame {
2927 // u1 frame_type = CHOP; /* 248-250 */
2928 // u2 offset_delta;
2929 // }
2930 else if (frame_type >= 248 && frame_type <= 250) {
2931 stackmap_p += 2;
2932 }
2933
2934 // same_frame_extended {
2935 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2936 // u2 offset_delta;
2937 // }
2938 else if (frame_type == 251) {
2939 stackmap_p += 2;
2940 }
2941
2942 // append_frame {
2943 // u1 frame_type = APPEND; /* 252-254 */
2944 // u2 offset_delta;
2945 // verification_type_info locals[frame_type - 251];
2946 // }
2947 else if (frame_type >= 252 && frame_type <= 254) {
2948 assert(stackmap_p + 2 <= stackmap_end,
2949 "no room for offset_delta");
2950 stackmap_p += 2;
2951 u1 len = frame_type - 251;
2952 for (u1 i = 0; i < len; i++) {
2953 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2954 calc_number_of_entries, frame_type, THREAD);
2955 }
2956 }
2957
2958 // full_frame {
2959 // u1 frame_type = FULL_FRAME; /* 255 */
2960 // u2 offset_delta;
2961 // u2 number_of_locals;
2962 // verification_type_info locals[number_of_locals];
2963 // u2 number_of_stack_items;
2964 // verification_type_info stack[number_of_stack_items];
2965 // }
2966 else if (frame_type == 255) {
2967 assert(stackmap_p + 2 + 2 <= stackmap_end,
2968 "no room for smallest full_frame");
2969 stackmap_p += 2;
2970
2971 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2972 stackmap_p += 2;
2973
2974 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2975 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2976 calc_number_of_entries, frame_type, THREAD);
2977 }
2978
2979 // Use the largest size for the number_of_stack_items, but only get
2980 // the right number of bytes.
2981 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2982 stackmap_p += 2;
2983
2984 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2985 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2986 calc_number_of_entries, frame_type, THREAD);
2987 }
2988 }
2989 } // end while there is a stack_map_frame
2990 assert(number_of_entries == calc_number_of_entries, "sanity check");
2991 } // end rewrite_cp_refs_in_stack_map_table()
2992
2993
2994 // Rewrite constant pool references in the verification type info
2995 // portion of the method's stackmap table. These "structures" are
2996 // adapted from the StackMapTable_attribute that is described in
2997 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2998 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2999 //
3000 // The verification_type_info structure is a u1 tag followed by 0 or
3001 // more bytes of data:
3002 //
3003 // union verification_type_info {
3004 // Top_variable_info;
3005 // Integer_variable_info;
3006 // Float_variable_info;
3007 // Long_variable_info;
3008 // Double_variable_info;
3009 // Null_variable_info;
3010 // UninitializedThis_variable_info;
3011 // Object_variable_info;
3012 // Uninitialized_variable_info;
3013 // }
3014 //
3015 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3016 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3017 u1 frame_type, TRAPS) {
3018
3019 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3020 u1 tag = *stackmap_p_ref;
3021 stackmap_p_ref++;
3022
3023 switch (tag) {
3024 // Top_variable_info {
3025 // u1 tag = ITEM_Top; /* 0 */
3026 // }
3027 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3028 case 0: // fall through
3029
3030 // Integer_variable_info {
3031 // u1 tag = ITEM_Integer; /* 1 */
3032 // }
3033 case ITEM_Integer: // fall through
3034
3035 // Float_variable_info {
3036 // u1 tag = ITEM_Float; /* 2 */
3037 // }
3038 case ITEM_Float: // fall through
3039
3040 // Double_variable_info {
3041 // u1 tag = ITEM_Double; /* 3 */
3042 // }
3043 case ITEM_Double: // fall through
3044
3045 // Long_variable_info {
3046 // u1 tag = ITEM_Long; /* 4 */
3047 // }
3048 case ITEM_Long: // fall through
3049
3050 // Null_variable_info {
3051 // u1 tag = ITEM_Null; /* 5 */
3052 // }
3053 case ITEM_Null: // fall through
3054
3055 // UninitializedThis_variable_info {
3056 // u1 tag = ITEM_UninitializedThis; /* 6 */
3057 // }
3058 case ITEM_UninitializedThis:
3059 // nothing more to do for the above tag types
3060 break;
3061
3062 // Object_variable_info {
3063 // u1 tag = ITEM_Object; /* 7 */
3064 // u2 cpool_index;
3065 // }
3066 case ITEM_Object:
3067 {
3068 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3069 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3070 u2 new_cp_index = find_new_index(cpool_index);
3071 if (new_cp_index != 0) {
3072 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3073 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3074 cpool_index = new_cp_index;
3075 }
3076 stackmap_p_ref += 2;
3077
3078 log_debug(redefine, class, stackmap)
3079 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3080 } break;
3081
3082 // Uninitialized_variable_info {
3083 // u1 tag = ITEM_Uninitialized; /* 8 */
3084 // u2 offset;
3085 // }
3086 case ITEM_Uninitialized:
3087 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3088 stackmap_p_ref += 2;
3089 break;
3090
3091 default:
3092 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3093 ShouldNotReachHere();
3094 break;
3095 } // end switch (tag)
3096 } // end rewrite_cp_refs_in_verification_type_info()
3097
3098
3099 // Change the constant pool associated with klass scratch_class to
3100 // scratch_cp. If shrink is true, then scratch_cp_length elements
3101 // are copied from scratch_cp to a smaller constant pool and the
3102 // smaller constant pool is associated with scratch_class.
3103 void VM_RedefineClasses::set_new_constant_pool(
3104 ClassLoaderData* loader_data,
3105 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3106 int scratch_cp_length, TRAPS) {
3107 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3108
3109 // scratch_cp is a merged constant pool and has enough space for a
3110 // worst case merge situation. We want to associate the minimum
3111 // sized constant pool with the klass to save space.
3112 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3113 constantPoolHandle smaller_cp(THREAD, cp);
3114
3115 // preserve version() value in the smaller copy
3116 int version = scratch_cp->version();
3117 assert(version != 0, "sanity check");
3118 smaller_cp->set_version(version);
3119
3120 // attach klass to new constant pool
3121 // reference to the cp holder is needed for copy_operands()
3122 smaller_cp->set_pool_holder(scratch_class);
3123
3124 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3125 if (HAS_PENDING_EXCEPTION) {
3126 // Exception is handled in the caller
3127 loader_data->add_to_deallocate_list(smaller_cp());
3128 return;
3129 }
3130 scratch_cp = smaller_cp;
3131
3132 // attach new constant pool to klass
3133 scratch_class->set_constants(scratch_cp());
3134 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3135
3136 int i; // for portability
3137
3138 // update each field in klass to use new constant pool indices as needed
3139 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3140 jshort cur_index = fs.name_index();
3141 jshort new_index = find_new_index(cur_index);
3142 if (new_index != 0) {
3143 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3144 fs.set_name_index(new_index);
3145 }
3146 cur_index = fs.signature_index();
3147 new_index = find_new_index(cur_index);
3148 if (new_index != 0) {
3149 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3150 fs.set_signature_index(new_index);
3151 }
3152 cur_index = fs.initval_index();
3153 new_index = find_new_index(cur_index);
3154 if (new_index != 0) {
3155 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3156 fs.set_initval_index(new_index);
3157 }
3158 cur_index = fs.generic_signature_index();
3159 new_index = find_new_index(cur_index);
3160 if (new_index != 0) {
3161 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3162 fs.set_generic_signature_index(new_index);
3163 }
3164 } // end for each field
3165
3166 // Update constant pool indices in the inner classes info to use
3167 // new constant indices as needed. The inner classes info is a
3168 // quadruple:
3169 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3170 InnerClassesIterator iter(scratch_class);
3171 for (; !iter.done(); iter.next()) {
3172 int cur_index = iter.inner_class_info_index();
3173 if (cur_index == 0) {
3174 continue; // JVM spec. allows null inner class refs so skip it
3175 }
3176 int new_index = find_new_index(cur_index);
3177 if (new_index != 0) {
3178 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3179 iter.set_inner_class_info_index(new_index);
3180 }
3181 cur_index = iter.outer_class_info_index();
3182 new_index = find_new_index(cur_index);
3183 if (new_index != 0) {
3184 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3185 iter.set_outer_class_info_index(new_index);
3186 }
3187 cur_index = iter.inner_name_index();
3188 new_index = find_new_index(cur_index);
3189 if (new_index != 0) {
3190 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3191 iter.set_inner_name_index(new_index);
3192 }
3193 } // end for each inner class
3194
3195 // Attach each method in klass to the new constant pool and update
3196 // to use new constant pool indices as needed:
3197 Array<Method*>* methods = scratch_class->methods();
3198 for (i = methods->length() - 1; i >= 0; i--) {
3199 methodHandle method(THREAD, methods->at(i));
3200 method->set_constants(scratch_cp());
3201
3202 int new_index = find_new_index(method->name_index());
3203 if (new_index != 0) {
3204 log_trace(redefine, class, constantpool)
3205 ("method-name_index change: %d to %d", method->name_index(), new_index);
3206 method->set_name_index(new_index);
3207 }
3208 new_index = find_new_index(method->signature_index());
3209 if (new_index != 0) {
3210 log_trace(redefine, class, constantpool)
3211 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3212 method->set_signature_index(new_index);
3213 }
3214 new_index = find_new_index(method->generic_signature_index());
3215 if (new_index != 0) {
3216 log_trace(redefine, class, constantpool)
3217 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3218 method->set_generic_signature_index(new_index);
3219 }
3220
3221 // Update constant pool indices in the method's checked exception
3222 // table to use new constant indices as needed.
3223 int cext_length = method->checked_exceptions_length();
3224 if (cext_length > 0) {
3225 CheckedExceptionElement * cext_table =
3226 method->checked_exceptions_start();
3227 for (int j = 0; j < cext_length; j++) {
3228 int cur_index = cext_table[j].class_cp_index;
3229 int new_index = find_new_index(cur_index);
3230 if (new_index != 0) {
3231 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3232 cext_table[j].class_cp_index = (u2)new_index;
3233 }
3234 } // end for each checked exception table entry
3235 } // end if there are checked exception table entries
3236
3237 // Update each catch type index in the method's exception table
3238 // to use new constant pool indices as needed. The exception table
3239 // holds quadruple entries of the form:
3240 // (beg_bci, end_bci, handler_bci, klass_index)
3241
3242 ExceptionTable ex_table(method());
3243 int ext_length = ex_table.length();
3244
3245 for (int j = 0; j < ext_length; j ++) {
3246 int cur_index = ex_table.catch_type_index(j);
3247 int new_index = find_new_index(cur_index);
3248 if (new_index != 0) {
3249 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3250 ex_table.set_catch_type_index(j, new_index);
3251 }
3252 } // end for each exception table entry
3253
3254 // Update constant pool indices in the method's local variable
3255 // table to use new constant indices as needed. The local variable
3256 // table hold sextuple entries of the form:
3257 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3258 int lvt_length = method->localvariable_table_length();
3259 if (lvt_length > 0) {
3260 LocalVariableTableElement * lv_table =
3261 method->localvariable_table_start();
3262 for (int j = 0; j < lvt_length; j++) {
3263 int cur_index = lv_table[j].name_cp_index;
3264 int new_index = find_new_index(cur_index);
3265 if (new_index != 0) {
3266 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3267 lv_table[j].name_cp_index = (u2)new_index;
3268 }
3269 cur_index = lv_table[j].descriptor_cp_index;
3270 new_index = find_new_index(cur_index);
3271 if (new_index != 0) {
3272 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3273 lv_table[j].descriptor_cp_index = (u2)new_index;
3274 }
3275 cur_index = lv_table[j].signature_cp_index;
3276 new_index = find_new_index(cur_index);
3277 if (new_index != 0) {
3278 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3279 lv_table[j].signature_cp_index = (u2)new_index;
3280 }
3281 } // end for each local variable table entry
3282 } // end if there are local variable table entries
3283
3284 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3285 } // end for each method
3286 } // end set_new_constant_pool()
3287
3288
3289 // Unevolving classes may point to methods of the_class directly
3290 // from their constant pool caches, itables, and/or vtables. We
3291 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3292 // to fix up these pointers.
3293
3294 // Adjust cpools and vtables closure
3295 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3296
3297 // This is a very busy routine. We don't want too much tracing
3298 // printed out.
3299 bool trace_name_printed = false;
3300 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3301
3302 // If the class being redefined is java.lang.Object, we need to fix all
3303 // array class vtables also
3304 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3305 k->vtable().adjust_method_entries(the_class, &trace_name_printed);
3306
3307 } else if (k->is_instance_klass()) {
3308 HandleMark hm(_thread);
3309 InstanceKlass *ik = InstanceKlass::cast(k);
3310
3311 // HotSpot specific optimization! HotSpot does not currently
3312 // support delegation from the bootstrap class loader to a
3313 // user-defined class loader. This means that if the bootstrap
3314 // class loader is the initiating class loader, then it will also
3315 // be the defining class loader. This also means that classes
3316 // loaded by the bootstrap class loader cannot refer to classes
3317 // loaded by a user-defined class loader. Note: a user-defined
3318 // class loader can delegate to the bootstrap class loader.
3319 //
3320 // If the current class being redefined has a user-defined class
3321 // loader as its defining class loader, then we can skip all
3322 // classes loaded by the bootstrap class loader.
3323 bool is_user_defined = (_the_class->class_loader() != NULL);
3324 if (is_user_defined && ik->class_loader() == NULL) {
3325 return;
3326 }
3327
3328 // Fix the vtable embedded in the_class and subclasses of the_class,
3329 // if one exists. We discard scratch_class and we don't keep an
3330 // InstanceKlass around to hold obsolete methods so we don't have
3331 // any other InstanceKlass embedded vtables to update. The vtable
3332 // holds the Method*s for virtual (but not final) methods.
3333 // Default methods, or concrete methods in interfaces are stored
3334 // in the vtable, so if an interface changes we need to check
3335 // adjust_method_entries() for every InstanceKlass, which will also
3336 // adjust the default method vtable indices.
3337 // We also need to adjust any default method entries that are
3338 // not yet in the vtable, because the vtable setup is in progress.
3339 // This must be done after we adjust the default_methods and
3340 // default_vtable_indices for methods already in the vtable.
3341 // If redefining Unsafe, walk all the vtables looking for entries.
3342 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3343 || _the_class == SystemDictionary::internal_Unsafe_klass()
3344 || ik->is_subtype_of(_the_class))) {
3345 // ik->vtable() creates a wrapper object; rm cleans it up
3346 ResourceMark rm(_thread);
3347
3348 ik->vtable().adjust_method_entries(the_class, &trace_name_printed);
3349 ik->adjust_default_methods(the_class, &trace_name_printed);
3350 }
3351
3352 // If the current class has an itable and we are either redefining an
3353 // interface or if the current class is a subclass of the_class, then
3354 // we potentially have to fix the itable. If we are redefining an
3355 // interface, then we have to call adjust_method_entries() for
3356 // every InstanceKlass that has an itable since there isn't a
3357 // subclass relationship between an interface and an InstanceKlass.
3358 // If redefining Unsafe, walk all the itables looking for entries.
3359 if (ik->itable_length() > 0 && (_the_class->is_interface()
3360 || _the_class == SystemDictionary::internal_Unsafe_klass()
3361 || ik->is_subclass_of(_the_class))) {
3362 ResourceMark rm(_thread);
3363 ik->itable().adjust_method_entries(the_class, &trace_name_printed);
3364 }
3365
3366 // The constant pools in other classes (other_cp) can refer to
3367 // methods in the_class. We have to update method information in
3368 // other_cp's cache. If other_cp has a previous version, then we
3369 // have to repeat the process for each previous version. The
3370 // constant pool cache holds the Method*s for non-virtual
3371 // methods and for virtual, final methods.
3372 //
3373 // Special case: if the current class is the_class, then new_cp
3374 // has already been attached to the_class and old_cp has already
3375 // been added as a previous version. The new_cp doesn't have any
3376 // cached references to old methods so it doesn't need to be
3377 // updated. We can simply start with the previous version(s) in
3378 // that case.
3379 constantPoolHandle other_cp;
3380 ConstantPoolCache* cp_cache;
3381
3382 if (ik != _the_class) {
3383 // this klass' constant pool cache may need adjustment
3384 other_cp = constantPoolHandle(ik->constants());
3385 cp_cache = other_cp->cache();
3386 if (cp_cache != NULL) {
3387 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3388 }
3389 }
3390
3391 // the previous versions' constant pool caches may need adjustment
3392 for (InstanceKlass* pv_node = ik->previous_versions();
3393 pv_node != NULL;
3394 pv_node = pv_node->previous_versions()) {
3395 cp_cache = pv_node->constants()->cache();
3396 if (cp_cache != NULL) {
3397 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3398 }
3399 }
3400 }
3401 }
3402
3403 // Clean method data for this class
3404 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3405 if (k->is_instance_klass()) {
3406 InstanceKlass *ik = InstanceKlass::cast(k);
3407 // Clean MethodData of this class's methods so they don't refer to
3408 // old methods that are no longer running.
3409 Array<Method*>* methods = ik->methods();
3410 int num_methods = methods->length();
3411 for (int index = 0; index < num_methods; ++index) {
3412 if (methods->at(index)->method_data() != NULL) {
3413 methods->at(index)->method_data()->clean_weak_method_links();
3414 }
3415 }
3416 }
3417 }
3418
3419 void VM_RedefineClasses::update_jmethod_ids() {
3420 for (int j = 0; j < _matching_methods_length; ++j) {
3421 Method* old_method = _matching_old_methods[j];
3422 jmethodID jmid = old_method->find_jmethod_id_or_null();
3423 if (jmid != NULL) {
3424 // There is a jmethodID, change it to point to the new method
3425 methodHandle new_method_h(_matching_new_methods[j]);
3426 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3427 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3428 "should be replaced");
3429 }
3430 }
3431 }
3432
3433 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3434 int emcp_method_count = 0;
3435 int obsolete_count = 0;
3436 int old_index = 0;
3437 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3438 Method* old_method = _matching_old_methods[j];
3439 Method* new_method = _matching_new_methods[j];
3440 Method* old_array_method;
3441
3442 // Maintain an old_index into the _old_methods array by skipping
3443 // deleted methods
3444 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3445 ++old_index;
3446 }
3447
3448 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3449 // The EMCP definition from JSR-163 requires the bytecodes to be
3450 // the same with the exception of constant pool indices which may
3451 // differ. However, the constants referred to by those indices
3452 // must be the same.
3453 //
3454 // We use methods_EMCP() for comparison since constant pool
3455 // merging can remove duplicate constant pool entries that were
3456 // present in the old method and removed from the rewritten new
3457 // method. A faster binary comparison function would consider the
3458 // old and new methods to be different when they are actually
3459 // EMCP.
3460 //
3461 // The old and new methods are EMCP and you would think that we
3462 // could get rid of one of them here and now and save some space.
3463 // However, the concept of EMCP only considers the bytecodes and
3464 // the constant pool entries in the comparison. Other things,
3465 // e.g., the line number table (LNT) or the local variable table
3466 // (LVT) don't count in the comparison. So the new (and EMCP)
3467 // method can have a new LNT that we need so we can't just
3468 // overwrite the new method with the old method.
3469 //
3470 // When this routine is called, we have already attached the new
3471 // methods to the_class so the old methods are effectively
3472 // overwritten. However, if an old method is still executing,
3473 // then the old method cannot be collected until sometime after
3474 // the old method call has returned. So the overwriting of old
3475 // methods by new methods will save us space except for those
3476 // (hopefully few) old methods that are still executing.
3477 //
3478 // A method refers to a ConstMethod* and this presents another
3479 // possible avenue to space savings. The ConstMethod* in the
3480 // new method contains possibly new attributes (LNT, LVT, etc).
3481 // At first glance, it seems possible to save space by replacing
3482 // the ConstMethod* in the old method with the ConstMethod*
3483 // from the new method. The old and new methods would share the
3484 // same ConstMethod* and we would save the space occupied by
3485 // the old ConstMethod*. However, the ConstMethod* contains
3486 // a back reference to the containing method. Sharing the
3487 // ConstMethod* between two methods could lead to confusion in
3488 // the code that uses the back reference. This would lead to
3489 // brittle code that could be broken in non-obvious ways now or
3490 // in the future.
3491 //
3492 // Another possibility is to copy the ConstMethod* from the new
3493 // method to the old method and then overwrite the new method with
3494 // the old method. Since the ConstMethod* contains the bytecodes
3495 // for the method embedded in the oop, this option would change
3496 // the bytecodes out from under any threads executing the old
3497 // method and make the thread's bcp invalid. Since EMCP requires
3498 // that the bytecodes be the same modulo constant pool indices, it
3499 // is straight forward to compute the correct new bcp in the new
3500 // ConstMethod* from the old bcp in the old ConstMethod*. The
3501 // time consuming part would be searching all the frames in all
3502 // of the threads to find all of the calls to the old method.
3503 //
3504 // It looks like we will have to live with the limited savings
3505 // that we get from effectively overwriting the old methods
3506 // when the new methods are attached to the_class.
3507
3508 // Count number of methods that are EMCP. The method will be marked
3509 // old but not obsolete if it is EMCP.
3510 emcp_method_count++;
3511
3512 // An EMCP method is _not_ obsolete. An obsolete method has a
3513 // different jmethodID than the current method. An EMCP method
3514 // has the same jmethodID as the current method. Having the
3515 // same jmethodID for all EMCP versions of a method allows for
3516 // a consistent view of the EMCP methods regardless of which
3517 // EMCP method you happen to have in hand. For example, a
3518 // breakpoint set in one EMCP method will work for all EMCP
3519 // versions of the method including the current one.
3520 } else {
3521 // mark obsolete methods as such
3522 old_method->set_is_obsolete();
3523 obsolete_count++;
3524
3525 // obsolete methods need a unique idnum so they become new entries in
3526 // the jmethodID cache in InstanceKlass
3527 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3528 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3529 if (num != ConstMethod::UNSET_IDNUM) {
3530 old_method->set_method_idnum(num);
3531 }
3532
3533 // With tracing we try not to "yack" too much. The position of
3534 // this trace assumes there are fewer obsolete methods than
3535 // EMCP methods.
3536 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3537 ResourceMark rm;
3538 log_trace(redefine, class, obsolete, mark)
3539 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3540 }
3541 }
3542 old_method->set_is_old();
3543 }
3544 for (int i = 0; i < _deleted_methods_length; ++i) {
3545 Method* old_method = _deleted_methods[i];
3546
3547 assert(!old_method->has_vtable_index(),
3548 "cannot delete methods with vtable entries");;
3549
3550 // Mark all deleted methods as old, obsolete and deleted
3551 old_method->set_is_deleted();
3552 old_method->set_is_old();
3553 old_method->set_is_obsolete();
3554 ++obsolete_count;
3555 // With tracing we try not to "yack" too much. The position of
3556 // this trace assumes there are fewer obsolete methods than
3557 // EMCP methods.
3558 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3559 ResourceMark rm;
3560 log_trace(redefine, class, obsolete, mark)
3561 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3562 }
3563 }
3564 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3565 "sanity check");
3566 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3567 return emcp_method_count;
3568 }
3569
3570 // This internal class transfers the native function registration from old methods
3571 // to new methods. It is designed to handle both the simple case of unchanged
3572 // native methods and the complex cases of native method prefixes being added and/or
3573 // removed.
3574 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3575 //
3576 // This class is used after the new methods have been installed in "the_class".
3577 //
3578 // So, for example, the following must be handled. Where 'm' is a method and
3579 // a number followed by an underscore is a prefix.
3580 //
3581 // Old Name New Name
3582 // Simple transfer to new method m -> m
3583 // Add prefix m -> 1_m
3584 // Remove prefix 1_m -> m
3585 // Simultaneous add of prefixes m -> 3_2_1_m
3586 // Simultaneous removal of prefixes 3_2_1_m -> m
3587 // Simultaneous add and remove 1_m -> 2_m
3588 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3589 //
3590 class TransferNativeFunctionRegistration {
3591 private:
3592 InstanceKlass* the_class;
3593 int prefix_count;
3594 char** prefixes;
3595
3596 // Recursively search the binary tree of possibly prefixed method names.
3597 // Iteration could be used if all agents were well behaved. Full tree walk is
3598 // more resilent to agents not cleaning up intermediate methods.
3599 // Branch at each depth in the binary tree is:
3600 // (1) without the prefix.
3601 // (2) with the prefix.
3602 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3603 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3604 Symbol* signature) {
3605 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3606 if (name_symbol != NULL) {
3607 Method* method = the_class->lookup_method(name_symbol, signature);
3608 if (method != NULL) {
3609 // Even if prefixed, intermediate methods must exist.
3610 if (method->is_native()) {
3611 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3612 return method;
3613 }
3614 if (depth < prefix_count) {
3615 // Try applying further prefixes (other than this one).
3616 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3617 if (method != NULL) {
3618 return method; // found
3619 }
3620
3621 // Try adding this prefix to the method name and see if it matches
3622 // another method name.
3623 char* prefix = prefixes[depth];
3624 size_t prefix_len = strlen(prefix);
3625 size_t trial_len = name_len + prefix_len;
3626 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3627 strcpy(trial_name_str, prefix);
3628 strcat(trial_name_str, name_str);
3629 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3630 signature);
3631 if (method != NULL) {
3632 // If found along this branch, it was prefixed, mark as such
3633 method->set_is_prefixed_native();
3634 return method; // found
3635 }
3636 }
3637 }
3638 }
3639 return NULL; // This whole branch bore nothing
3640 }
3641
3642 // Return the method name with old prefixes stripped away.
3643 char* method_name_without_prefixes(Method* method) {
3644 Symbol* name = method->name();
3645 char* name_str = name->as_utf8();
3646
3647 // Old prefixing may be defunct, strip prefixes, if any.
3648 for (int i = prefix_count-1; i >= 0; i--) {
3649 char* prefix = prefixes[i];
3650 size_t prefix_len = strlen(prefix);
3651 if (strncmp(prefix, name_str, prefix_len) == 0) {
3652 name_str += prefix_len;
3653 }
3654 }
3655 return name_str;
3656 }
3657
3658 // Strip any prefixes off the old native method, then try to find a
3659 // (possibly prefixed) new native that matches it.
3660 Method* strip_and_search_for_new_native(Method* method) {
3661 ResourceMark rm;
3662 char* name_str = method_name_without_prefixes(method);
3663 return search_prefix_name_space(0, name_str, strlen(name_str),
3664 method->signature());
3665 }
3666
3667 public:
3668
3669 // Construct a native method transfer processor for this class.
3670 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3671 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3672
3673 the_class = _the_class;
3674 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3675 }
3676
3677 // Attempt to transfer any of the old or deleted methods that are native
3678 void transfer_registrations(Method** old_methods, int methods_length) {
3679 for (int j = 0; j < methods_length; j++) {
3680 Method* old_method = old_methods[j];
3681
3682 if (old_method->is_native() && old_method->has_native_function()) {
3683 Method* new_method = strip_and_search_for_new_native(old_method);
3684 if (new_method != NULL) {
3685 // Actually set the native function in the new method.
3686 // Redefine does not send events (except CFLH), certainly not this
3687 // behind the scenes re-registration.
3688 new_method->set_native_function(old_method->native_function(),
3689 !Method::native_bind_event_is_interesting);
3690 }
3691 }
3692 }
3693 }
3694 };
3695
3696 // Don't lose the association between a native method and its JNI function.
3697 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3698 TransferNativeFunctionRegistration transfer(the_class);
3699 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3700 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3701 }
3702
3703 // Deoptimize all compiled code that depends on this class.
3704 //
3705 // If the can_redefine_classes capability is obtained in the onload
3706 // phase then the compiler has recorded all dependencies from startup.
3707 // In that case we need only deoptimize and throw away all compiled code
3708 // that depends on the class.
3709 //
3710 // If can_redefine_classes is obtained sometime after the onload
3711 // phase then the dependency information may be incomplete. In that case
3712 // the first call to RedefineClasses causes all compiled code to be
3713 // thrown away. As can_redefine_classes has been obtained then
3714 // all future compilations will record dependencies so second and
3715 // subsequent calls to RedefineClasses need only throw away code
3716 // that depends on the class.
3717 //
3718 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3719 assert_locked_or_safepoint(Compile_lock);
3720
3721 // All dependencies have been recorded from startup or this is a second or
3722 // subsequent use of RedefineClasses
3723 if (JvmtiExport::all_dependencies_are_recorded()) {
3724 CodeCache::flush_evol_dependents_on(ik);
3725 } else {
3726 CodeCache::mark_all_nmethods_for_deoptimization();
3727
3728 ResourceMark rm(THREAD);
3729 DeoptimizationMarker dm;
3730
3731 // Deoptimize all activations depending on marked nmethods
3732 Deoptimization::deoptimize_dependents();
3733
3734 // Make the dependent methods not entrant
3735 CodeCache::make_marked_nmethods_not_entrant();
3736
3737 // From now on we know that the dependency information is complete
3738 JvmtiExport::set_all_dependencies_are_recorded(true);
3739 }
3740 }
3741
3742 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3743 Method* old_method;
3744 Method* new_method;
3745
3746 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3747 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3748 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3749 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3750
3751 _matching_methods_length = 0;
3752 _deleted_methods_length = 0;
3753 _added_methods_length = 0;
3754
3755 int nj = 0;
3756 int oj = 0;
3757 while (true) {
3758 if (oj >= _old_methods->length()) {
3759 if (nj >= _new_methods->length()) {
3760 break; // we've looked at everything, done
3761 }
3762 // New method at the end
3763 new_method = _new_methods->at(nj);
3764 _added_methods[_added_methods_length++] = new_method;
3765 ++nj;
3766 } else if (nj >= _new_methods->length()) {
3767 // Old method, at the end, is deleted
3768 old_method = _old_methods->at(oj);
3769 _deleted_methods[_deleted_methods_length++] = old_method;
3770 ++oj;
3771 } else {
3772 old_method = _old_methods->at(oj);
3773 new_method = _new_methods->at(nj);
3774 if (old_method->name() == new_method->name()) {
3775 if (old_method->signature() == new_method->signature()) {
3776 _matching_old_methods[_matching_methods_length ] = old_method;
3777 _matching_new_methods[_matching_methods_length++] = new_method;
3778 ++nj;
3779 ++oj;
3780 } else {
3781 // added overloaded have already been moved to the end,
3782 // so this is a deleted overloaded method
3783 _deleted_methods[_deleted_methods_length++] = old_method;
3784 ++oj;
3785 }
3786 } else { // names don't match
3787 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3788 // new method
3789 _added_methods[_added_methods_length++] = new_method;
3790 ++nj;
3791 } else {
3792 // deleted method
3793 _deleted_methods[_deleted_methods_length++] = old_method;
3794 ++oj;
3795 }
3796 }
3797 }
3798 }
3799 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3800 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3801 }
3802
3803
3804 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3805 InstanceKlass* scratch_class) {
3806 // Swap annotation fields values
3807 Annotations* old_annotations = the_class->annotations();
3808 the_class->set_annotations(scratch_class->annotations());
3809 scratch_class->set_annotations(old_annotations);
3810 }
3811
3812
3813 // Install the redefinition of a class:
3814 // - house keeping (flushing breakpoints and caches, deoptimizing
3815 // dependent compiled code)
3816 // - replacing parts in the_class with parts from scratch_class
3817 // - adding a weak reference to track the obsolete but interesting
3818 // parts of the_class
3819 // - adjusting constant pool caches and vtables in other classes
3820 // that refer to methods in the_class. These adjustments use the
3821 // ClassLoaderDataGraph::classes_do() facility which only allows
3822 // a helper method to be specified. The interesting parameters
3823 // that we would like to pass to the helper method are saved in
3824 // static global fields in the VM operation.
3825 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3826 InstanceKlass* scratch_class, TRAPS) {
3827
3828 HandleMark hm(THREAD); // make sure handles from this call are freed
3829
3830 if (log_is_enabled(Info, redefine, class, timer)) {
3831 _timer_rsc_phase1.start();
3832 }
3833
3834 InstanceKlass* the_class = get_ik(the_jclass);
3835
3836 // Remove all breakpoints in methods of this class
3837 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3838 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3839
3840 // Deoptimize all compiled code that depends on this class
3841 flush_dependent_code(the_class, THREAD);
3842
3843 _old_methods = the_class->methods();
3844 _new_methods = scratch_class->methods();
3845 _the_class = the_class;
3846 compute_added_deleted_matching_methods();
3847 update_jmethod_ids();
3848
3849 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
3850
3851 // Attach new constant pool to the original klass. The original
3852 // klass still refers to the old constant pool (for now).
3853 scratch_class->constants()->set_pool_holder(the_class);
3854
3855 #if 0
3856 // In theory, with constant pool merging in place we should be able
3857 // to save space by using the new, merged constant pool in place of
3858 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3859 // the klass version we are replacing now and any constant pool(s) in
3860 // previous versions of klass. Nice theory, doesn't work in practice.
3861 // When this code is enabled, even simple programs throw NullPointer
3862 // exceptions. I'm guessing that this is caused by some constant pool
3863 // cache difference between the new, merged constant pool and the
3864 // constant pool that was just being used by the klass. I'm keeping
3865 // this code around to archive the idea, but the code has to remain
3866 // disabled for now.
3867
3868 // Attach each old method to the new constant pool. This can be
3869 // done here since we are past the bytecode verification and
3870 // constant pool optimization phases.
3871 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3872 Method* method = _old_methods->at(i);
3873 method->set_constants(scratch_class->constants());
3874 }
3875
3876 // NOTE: this doesn't work because you can redefine the same class in two
3877 // threads, each getting their own constant pool data appended to the
3878 // original constant pool. In order for the new methods to work when they
3879 // become old methods, they need to keep their updated copy of the constant pool.
3880
3881 {
3882 // walk all previous versions of the klass
3883 InstanceKlass *ik = the_class;
3884 PreviousVersionWalker pvw(ik);
3885 do {
3886 ik = pvw.next_previous_version();
3887 if (ik != NULL) {
3888
3889 // attach previous version of klass to the new constant pool
3890 ik->set_constants(scratch_class->constants());
3891
3892 // Attach each method in the previous version of klass to the
3893 // new constant pool
3894 Array<Method*>* prev_methods = ik->methods();
3895 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3896 Method* method = prev_methods->at(i);
3897 method->set_constants(scratch_class->constants());
3898 }
3899 }
3900 } while (ik != NULL);
3901 }
3902 #endif
3903
3904 // Replace methods and constantpool
3905 the_class->set_methods(_new_methods);
3906 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3907 // and to be able to undo operation easily.
3908
3909 Array<int>* old_ordering = the_class->method_ordering();
3910 the_class->set_method_ordering(scratch_class->method_ordering());
3911 scratch_class->set_method_ordering(old_ordering);
3912
3913 ConstantPool* old_constants = the_class->constants();
3914 the_class->set_constants(scratch_class->constants());
3915 scratch_class->set_constants(old_constants); // See the previous comment.
3916 #if 0
3917 // We are swapping the guts of "the new class" with the guts of "the
3918 // class". Since the old constant pool has just been attached to "the
3919 // new class", it seems logical to set the pool holder in the old
3920 // constant pool also. However, doing this will change the observable
3921 // class hierarchy for any old methods that are still executing. A
3922 // method can query the identity of its "holder" and this query uses
3923 // the method's constant pool link to find the holder. The change in
3924 // holding class from "the class" to "the new class" can confuse
3925 // things.
3926 //
3927 // Setting the old constant pool's holder will also cause
3928 // verification done during vtable initialization below to fail.
3929 // During vtable initialization, the vtable's class is verified to be
3930 // a subtype of the method's holder. The vtable's class is "the
3931 // class" and the method's holder is gotten from the constant pool
3932 // link in the method itself. For "the class"'s directly implemented
3933 // methods, the method holder is "the class" itself (as gotten from
3934 // the new constant pool). The check works fine in this case. The
3935 // check also works fine for methods inherited from super classes.
3936 //
3937 // Miranda methods are a little more complicated. A miranda method is
3938 // provided by an interface when the class implementing the interface
3939 // does not provide its own method. These interfaces are implemented
3940 // internally as an InstanceKlass. These special instanceKlasses
3941 // share the constant pool of the class that "implements" the
3942 // interface. By sharing the constant pool, the method holder of a
3943 // miranda method is the class that "implements" the interface. In a
3944 // non-redefine situation, the subtype check works fine. However, if
3945 // the old constant pool's pool holder is modified, then the check
3946 // fails because there is no class hierarchy relationship between the
3947 // vtable's class and "the new class".
3948
3949 old_constants->set_pool_holder(scratch_class());
3950 #endif
3951
3952 // track number of methods that are EMCP for add_previous_version() call below
3953 int emcp_method_count = check_methods_and_mark_as_obsolete();
3954 transfer_old_native_function_registrations(the_class);
3955
3956 // The class file bytes from before any retransformable agents mucked
3957 // with them was cached on the scratch class, move to the_class.
3958 // Note: we still want to do this if nothing needed caching since it
3959 // should get cleared in the_class too.
3960 if (the_class->get_cached_class_file() == 0) {
3961 // the_class doesn't have a cache yet so copy it
3962 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3963 }
3964 else if (scratch_class->get_cached_class_file() !=
3965 the_class->get_cached_class_file()) {
3966 // The same class can be present twice in the scratch classes list or there
3967 // are multiple concurrent RetransformClasses calls on different threads.
3968 // In such cases we have to deallocate scratch_class cached_class_file.
3969 os::free(scratch_class->get_cached_class_file());
3970 }
3971
3972 // NULL out in scratch class to not delete twice. The class to be redefined
3973 // always owns these bytes.
3974 scratch_class->set_cached_class_file(NULL);
3975
3976 // Replace inner_classes
3977 Array<u2>* old_inner_classes = the_class->inner_classes();
3978 the_class->set_inner_classes(scratch_class->inner_classes());
3979 scratch_class->set_inner_classes(old_inner_classes);
3980
3981 // Initialize the vtable and interface table after
3982 // methods have been rewritten
3983 {
3984 ResourceMark rm(THREAD);
3985 // no exception should happen here since we explicitly
3986 // do not check loader constraints.
3987 // compare_and_normalize_class_versions has already checked:
3988 // - classloaders unchanged, signatures unchanged
3989 // - all instanceKlasses for redefined classes reused & contents updated
3990 the_class->vtable().initialize_vtable(false, THREAD);
3991 the_class->itable().initialize_itable(false, THREAD);
3992 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3993 }
3994
3995 // Leave arrays of jmethodIDs and itable index cache unchanged
3996
3997 // Copy the "source file name" attribute from new class version
3998 the_class->set_source_file_name_index(
3999 scratch_class->source_file_name_index());
4000
4001 // Copy the "source debug extension" attribute from new class version
4002 the_class->set_source_debug_extension(
4003 scratch_class->source_debug_extension(),
4004 scratch_class->source_debug_extension() == NULL ? 0 :
4005 (int)strlen(scratch_class->source_debug_extension()));
4006
4007 // Use of javac -g could be different in the old and the new
4008 if (scratch_class->access_flags().has_localvariable_table() !=
4009 the_class->access_flags().has_localvariable_table()) {
4010
4011 AccessFlags flags = the_class->access_flags();
4012 if (scratch_class->access_flags().has_localvariable_table()) {
4013 flags.set_has_localvariable_table();
4014 } else {
4015 flags.clear_has_localvariable_table();
4016 }
4017 the_class->set_access_flags(flags);
4018 }
4019
4020 swap_annotations(the_class, scratch_class);
4021
4022 // Replace minor version number of class file
4023 u2 old_minor_version = the_class->minor_version();
4024 the_class->set_minor_version(scratch_class->minor_version());
4025 scratch_class->set_minor_version(old_minor_version);
4026
4027 // Replace major version number of class file
4028 u2 old_major_version = the_class->major_version();
4029 the_class->set_major_version(scratch_class->major_version());
4030 scratch_class->set_major_version(old_major_version);
4031
4032 // Replace CP indexes for class and name+type of enclosing method
4033 u2 old_class_idx = the_class->enclosing_method_class_index();
4034 u2 old_method_idx = the_class->enclosing_method_method_index();
4035 the_class->set_enclosing_method_indices(
4036 scratch_class->enclosing_method_class_index(),
4037 scratch_class->enclosing_method_method_index());
4038 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4039
4040 // Replace fingerprint data
4041 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4042 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4043
4044 the_class->set_has_been_redefined();
4045
4046 if (!the_class->should_be_initialized()) {
4047 // Class was already initialized, so AOT has only seen the original version.
4048 // We need to let AOT look at it again.
4049 AOTLoader::load_for_klass(the_class, THREAD);
4050 }
4051
4052 // keep track of previous versions of this class
4053 the_class->add_previous_version(scratch_class, emcp_method_count);
4054
4055 _timer_rsc_phase1.stop();
4056 if (log_is_enabled(Info, redefine, class, timer)) {
4057 _timer_rsc_phase2.start();
4058 }
4059
4060 // Adjust constantpool caches and vtables for all classes
4061 // that reference methods of the evolved class.
4062 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4063 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4064
4065 if (the_class->oop_map_cache() != NULL) {
4066 // Flush references to any obsolete methods from the oop map cache
4067 // so that obsolete methods are not pinned.
4068 the_class->oop_map_cache()->flush_obsolete_entries();
4069 }
4070
4071 increment_class_counter((InstanceKlass *)the_class, THREAD);
4072 {
4073 ResourceMark rm(THREAD);
4074 // increment the classRedefinedCount field in the_class and in any
4075 // direct and indirect subclasses of the_class
4076 log_info(redefine, class, load)
4077 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4078 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4079 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4080 the_class->external_name(),
4081 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4082
4083 }
4084 _timer_rsc_phase2.stop();
4085 } // end redefine_single_class()
4086
4087
4088 // Increment the classRedefinedCount field in the specific InstanceKlass
4089 // and in all direct and indirect subclasses.
4090 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4091 oop class_mirror = ik->java_mirror();
4092 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4093 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4094 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4095
4096 if (class_oop != _the_class) {
4097 // _the_class count is printed at end of redefine_single_class()
4098 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4099 }
4100
4101 for (Klass *subk = ik->subklass(); subk != NULL;
4102 subk = subk->next_sibling()) {
4103 if (subk->is_instance_klass()) {
4104 // Only update instanceKlasses
4105 InstanceKlass *subik = InstanceKlass::cast(subk);
4106 // recursively do subclasses of the current subclass
4107 increment_class_counter(subik, THREAD);
4108 }
4109 }
4110 }
4111
4112 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4113 bool no_old_methods = true; // be optimistic
4114
4115 // Both array and instance classes have vtables.
4116 // a vtable should never contain old or obsolete methods
4117 ResourceMark rm(_thread);
4118 if (k->vtable_length() > 0 &&
4119 !k->vtable().check_no_old_or_obsolete_entries()) {
4120 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4121 log_trace(redefine, class, obsolete, metadata)
4122 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4123 k->signature_name());
4124 k->vtable().dump_vtable();
4125 }
4126 no_old_methods = false;
4127 }
4128
4129 if (k->is_instance_klass()) {
4130 HandleMark hm(_thread);
4131 InstanceKlass *ik = InstanceKlass::cast(k);
4132
4133 // an itable should never contain old or obsolete methods
4134 if (ik->itable_length() > 0 &&
4135 !ik->itable().check_no_old_or_obsolete_entries()) {
4136 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4137 log_trace(redefine, class, obsolete, metadata)
4138 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4139 ik->signature_name());
4140 ik->itable().dump_itable();
4141 }
4142 no_old_methods = false;
4143 }
4144
4145 // the constant pool cache should never contain non-deleted old or obsolete methods
4146 if (ik->constants() != NULL &&
4147 ik->constants()->cache() != NULL &&
4148 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4149 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4150 log_trace(redefine, class, obsolete, metadata)
4151 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4152 ik->signature_name());
4153 ik->constants()->cache()->dump_cache();
4154 }
4155 no_old_methods = false;
4156 }
4157 }
4158
4159 // print and fail guarantee if old methods are found.
4160 if (!no_old_methods) {
4161 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4162 dump_methods();
4163 } else {
4164 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4165 "to see more info about the following guarantee() failure.");
4166 }
4167 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4168 }
4169 }
4170
4171
4172 void VM_RedefineClasses::dump_methods() {
4173 int j;
4174 log_trace(redefine, class, dump)("_old_methods --");
4175 for (j = 0; j < _old_methods->length(); ++j) {
4176 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4177 Method* m = _old_methods->at(j);
4178 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4179 m->access_flags().print_on(&log_stream);
4180 log_stream.print(" -- ");
4181 m->print_name(&log_stream);
4182 log_stream.cr();
4183 }
4184 log_trace(redefine, class, dump)("_new_methods --");
4185 for (j = 0; j < _new_methods->length(); ++j) {
4186 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4187 Method* m = _new_methods->at(j);
4188 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4189 m->access_flags().print_on(&log_stream);
4190 log_stream.print(" -- ");
4191 m->print_name(&log_stream);
4192 log_stream.cr();
4193 }
4194 log_trace(redefine, class, dump)("_matching_methods --");
4195 for (j = 0; j < _matching_methods_length; ++j) {
4196 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4197 Method* m = _matching_old_methods[j];
4198 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4199 m->access_flags().print_on(&log_stream);
4200 log_stream.print(" -- ");
4201 m->print_name();
4202 log_stream.cr();
4203
4204 m = _matching_new_methods[j];
4205 log_stream.print(" (%5d) ", m->vtable_index());
4206 m->access_flags().print_on(&log_stream);
4207 log_stream.cr();
4208 }
4209 log_trace(redefine, class, dump)("_deleted_methods --");
4210 for (j = 0; j < _deleted_methods_length; ++j) {
4211 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4212 Method* m = _deleted_methods[j];
4213 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4214 m->access_flags().print_on(&log_stream);
4215 log_stream.print(" -- ");
4216 m->print_name(&log_stream);
4217 log_stream.cr();
4218 }
4219 log_trace(redefine, class, dump)("_added_methods --");
4220 for (j = 0; j < _added_methods_length; ++j) {
4221 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4222 Method* m = _added_methods[j];
4223 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4224 m->access_flags().print_on(&log_stream);
4225 log_stream.print(" -- ");
4226 m->print_name(&log_stream);
4227 log_stream.cr();
4228 }
4229 }
4230
4231 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4232 VM_Operation::print_on_error(st);
4233 if (_the_class != NULL) {
4234 ResourceMark rm;
4235 st->print_cr(", redefining class %s", _the_class->external_name());
4236 }
4237 }