1 /*
2 * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/metadataOnStackMark.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/verifier.hpp"
31 #include "code/codeCache.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "interpreter/rewriter.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/metadataFactory.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/fieldStreams.hpp"
42 #include "oops/klassVtable.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "prims/jvmtiImpl.hpp"
45 #include "prims/jvmtiRedefineClasses.hpp"
46 #include "prims/jvmtiThreadState.inline.hpp"
47 #include "prims/resolvedMethodTable.hpp"
48 #include "prims/methodComparator.hpp"
49 #include "runtime/deoptimization.hpp"
50 #include "runtime/relocator.hpp"
51 #include "utilities/bitMap.inline.hpp"
52 #include "utilities/events.hpp"
53
54 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
55 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
56 Method** VM_RedefineClasses::_matching_old_methods = NULL;
57 Method** VM_RedefineClasses::_matching_new_methods = NULL;
58 Method** VM_RedefineClasses::_deleted_methods = NULL;
59 Method** VM_RedefineClasses::_added_methods = NULL;
60 int VM_RedefineClasses::_matching_methods_length = 0;
61 int VM_RedefineClasses::_deleted_methods_length = 0;
62 int VM_RedefineClasses::_added_methods_length = 0;
63 Klass* VM_RedefineClasses::_the_class = NULL;
64
65
66 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
67 const jvmtiClassDefinition *class_defs,
68 JvmtiClassLoadKind class_load_kind) {
69 _class_count = class_count;
70 _class_defs = class_defs;
71 _class_load_kind = class_load_kind;
72 _any_class_has_resolved_methods = false;
73 _res = JVMTI_ERROR_NONE;
74 }
75
76 static inline InstanceKlass* get_ik(jclass def) {
77 oop mirror = JNIHandles::resolve_non_null(def);
78 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
79 }
80
81 // If any of the classes are being redefined, wait
82 // Parallel constant pool merging leads to indeterminate constant pools.
83 void VM_RedefineClasses::lock_classes() {
84 MutexLocker ml(RedefineClasses_lock);
85 bool has_redefined;
86 do {
87 has_redefined = false;
88 // Go through classes each time until none are being redefined.
89 for (int i = 0; i < _class_count; i++) {
90 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
91 RedefineClasses_lock->wait();
92 has_redefined = true;
93 break; // for loop
94 }
95 }
96 } while (has_redefined);
97 for (int i = 0; i < _class_count; i++) {
98 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
99 }
100 RedefineClasses_lock->notify_all();
101 }
102
103 void VM_RedefineClasses::unlock_classes() {
104 MutexLocker ml(RedefineClasses_lock);
105 for (int i = 0; i < _class_count; i++) {
106 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
107 "should be being redefined to get here");
108 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
109 }
110 RedefineClasses_lock->notify_all();
111 }
112
113 bool VM_RedefineClasses::doit_prologue() {
114 if (_class_count == 0) {
115 _res = JVMTI_ERROR_NONE;
116 return false;
117 }
118 if (_class_defs == NULL) {
119 _res = JVMTI_ERROR_NULL_POINTER;
120 return false;
121 }
122 for (int i = 0; i < _class_count; i++) {
123 if (_class_defs[i].klass == NULL) {
124 _res = JVMTI_ERROR_INVALID_CLASS;
125 return false;
126 }
127 if (_class_defs[i].class_byte_count == 0) {
128 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
129 return false;
130 }
131 if (_class_defs[i].class_bytes == NULL) {
132 _res = JVMTI_ERROR_NULL_POINTER;
133 return false;
134 }
135
136 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
137 // classes for primitives and arrays and vm anonymous classes cannot be redefined
138 // check here so following code can assume these classes are InstanceKlass
139 if (!is_modifiable_class(mirror)) {
140 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
141 return false;
142 }
143 }
144
145 // Start timer after all the sanity checks; not quite accurate, but
146 // better than adding a bunch of stop() calls.
147 if (log_is_enabled(Info, redefine, class, timer)) {
148 _timer_vm_op_prologue.start();
149 }
150
151 lock_classes();
152 // We first load new class versions in the prologue, because somewhere down the
153 // call chain it is required that the current thread is a Java thread.
154 _res = load_new_class_versions(Thread::current());
155 if (_res != JVMTI_ERROR_NONE) {
156 // free any successfully created classes, since none are redefined
157 for (int i = 0; i < _class_count; i++) {
158 if (_scratch_classes[i] != NULL) {
159 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
160 // Free the memory for this class at class unloading time. Not before
161 // because CMS might think this is still live.
162 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
163 }
164 }
165 // Free os::malloc allocated memory in load_new_class_version.
166 os::free(_scratch_classes);
167 _timer_vm_op_prologue.stop();
168 unlock_classes();
169 return false;
170 }
171
172 _timer_vm_op_prologue.stop();
173 return true;
174 }
175
176 void VM_RedefineClasses::doit() {
177 Thread *thread = Thread::current();
178
179 #if INCLUDE_CDS
180 if (UseSharedSpaces) {
181 // Sharing is enabled so we remap the shared readonly space to
182 // shared readwrite, private just in case we need to redefine
183 // a shared class. We do the remap during the doit() phase of
184 // the safepoint to be safer.
185 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
186 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
187 _res = JVMTI_ERROR_INTERNAL;
188 return;
189 }
190 }
191 #endif
192
193 // Mark methods seen on stack and everywhere else so old methods are not
194 // cleaned up if they're on the stack.
195 MetadataOnStackMark md_on_stack(true);
196 HandleMark hm(thread); // make sure any handles created are deleted
197 // before the stack walk again.
198
199 for (int i = 0; i < _class_count; i++) {
200 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
201 }
202
203 // Clean out MethodData pointing to old Method*
204 // Have to do this after all classes are redefined and all methods that
205 // are redefined are marked as old.
206 MethodDataCleaner clean_weak_method_links;
207 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
208
209 // JSR-292 support
210 if (_any_class_has_resolved_methods) {
211 bool trace_name_printed = false;
212 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
213 }
214
215 // Disable any dependent concurrent compilations
216 SystemDictionary::notice_modification();
217
218 // Set flag indicating that some invariants are no longer true.
219 // See jvmtiExport.hpp for detailed explanation.
220 JvmtiExport::set_has_redefined_a_class();
221
222 // check_class() is optionally called for product bits, but is
223 // always called for non-product bits.
224 #ifdef PRODUCT
225 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
226 #endif
227 log_trace(redefine, class, obsolete, metadata)("calling check_class");
228 CheckClass check_class(thread);
229 ClassLoaderDataGraph::classes_do(&check_class);
230 #ifdef PRODUCT
231 }
232 #endif
233 }
234
235 void VM_RedefineClasses::doit_epilogue() {
236 unlock_classes();
237
238 // Free os::malloc allocated memory.
239 os::free(_scratch_classes);
240
241 // Reset the_class to null for error printing.
242 _the_class = NULL;
243
244 if (log_is_enabled(Info, redefine, class, timer)) {
245 // Used to have separate timers for "doit" and "all", but the timer
246 // overhead skewed the measurements.
247 julong doit_time = _timer_rsc_phase1.milliseconds() +
248 _timer_rsc_phase2.milliseconds();
249 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
250
251 log_info(redefine, class, timer)
252 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
253 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
254 log_info(redefine, class, timer)
255 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
256 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
257 }
258 }
259
260 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
261 // classes for primitives cannot be redefined
262 if (java_lang_Class::is_primitive(klass_mirror)) {
263 return false;
264 }
265 Klass* k = java_lang_Class::as_Klass(klass_mirror);
266 // classes for arrays cannot be redefined
267 if (k == NULL || !k->is_instance_klass()) {
268 return false;
269 }
270
271 // Cannot redefine or retransform an anonymous class.
272 if (InstanceKlass::cast(k)->is_anonymous()) {
273 return false;
274 }
275 return true;
276 }
277
278 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
279 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
280 // direct CP entries, there is just the current entry to append. For
281 // indirect and double-indirect CP entries, there are zero or more
282 // referenced CP entries along with the current entry to append.
283 // Indirect and double-indirect CP entries are handled by recursive
284 // calls to append_entry() as needed. The referenced CP entries are
285 // always appended to *merge_cp_p before the referee CP entry. These
286 // referenced CP entries may already exist in *merge_cp_p in which case
287 // there is nothing extra to append and only the current entry is
288 // appended.
289 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
290 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
291 TRAPS) {
292
293 // append is different depending on entry tag type
294 switch (scratch_cp->tag_at(scratch_i).value()) {
295
296 // The old verifier is implemented outside the VM. It loads classes,
297 // but does not resolve constant pool entries directly so we never
298 // see Class entries here with the old verifier. Similarly the old
299 // verifier does not like Class entries in the input constant pool.
300 // The split-verifier is implemented in the VM so it can optionally
301 // and directly resolve constant pool entries to load classes. The
302 // split-verifier can accept either Class entries or UnresolvedClass
303 // entries in the input constant pool. We revert the appended copy
304 // back to UnresolvedClass so that either verifier will be happy
305 // with the constant pool entry.
306 //
307 // this is an indirect CP entry so it needs special handling
308 case JVM_CONSTANT_Class:
309 case JVM_CONSTANT_UnresolvedClass:
310 {
311 int name_i = scratch_cp->klass_name_index_at(scratch_i);
312 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
313 merge_cp_length_p, THREAD);
314
315 if (new_name_i != name_i) {
316 log_trace(redefine, class, constantpool)
317 ("Class entry@%d name_index change: %d to %d",
318 *merge_cp_length_p, name_i, new_name_i);
319 }
320
321 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
322 if (scratch_i != *merge_cp_length_p) {
323 // The new entry in *merge_cp_p is at a different index than
324 // the new entry in scratch_cp so we need to map the index values.
325 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
326 }
327 (*merge_cp_length_p)++;
328 } break;
329
330 // these are direct CP entries so they can be directly appended,
331 // but double and long take two constant pool entries
332 case JVM_CONSTANT_Double: // fall through
333 case JVM_CONSTANT_Long:
334 {
335 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
336 THREAD);
337
338 if (scratch_i != *merge_cp_length_p) {
339 // The new entry in *merge_cp_p is at a different index than
340 // the new entry in scratch_cp so we need to map the index values.
341 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
342 }
343 (*merge_cp_length_p) += 2;
344 } break;
345
346 // these are direct CP entries so they can be directly appended
347 case JVM_CONSTANT_Float: // fall through
348 case JVM_CONSTANT_Integer: // fall through
349 case JVM_CONSTANT_Utf8: // fall through
350
351 // This was an indirect CP entry, but it has been changed into
352 // Symbol*s so this entry can be directly appended.
353 case JVM_CONSTANT_String: // fall through
354 {
355 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
356 THREAD);
357
358 if (scratch_i != *merge_cp_length_p) {
359 // The new entry in *merge_cp_p is at a different index than
360 // the new entry in scratch_cp so we need to map the index values.
361 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
362 }
363 (*merge_cp_length_p)++;
364 } break;
365
366 // this is an indirect CP entry so it needs special handling
367 case JVM_CONSTANT_NameAndType:
368 {
369 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
370 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
371 merge_cp_length_p, THREAD);
372
373 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
374 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
375 merge_cp_p, merge_cp_length_p,
376 THREAD);
377
378 // If the referenced entries already exist in *merge_cp_p, then
379 // both new_name_ref_i and new_signature_ref_i will both be 0.
380 // In that case, all we are appending is the current entry.
381 if (new_name_ref_i != name_ref_i) {
382 log_trace(redefine, class, constantpool)
383 ("NameAndType entry@%d name_ref_index change: %d to %d",
384 *merge_cp_length_p, name_ref_i, new_name_ref_i);
385 }
386 if (new_signature_ref_i != signature_ref_i) {
387 log_trace(redefine, class, constantpool)
388 ("NameAndType entry@%d signature_ref_index change: %d to %d",
389 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
390 }
391
392 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
393 new_name_ref_i, new_signature_ref_i);
394 if (scratch_i != *merge_cp_length_p) {
395 // The new entry in *merge_cp_p is at a different index than
396 // the new entry in scratch_cp so we need to map the index values.
397 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
398 }
399 (*merge_cp_length_p)++;
400 } break;
401
402 // this is a double-indirect CP entry so it needs special handling
403 case JVM_CONSTANT_Fieldref: // fall through
404 case JVM_CONSTANT_InterfaceMethodref: // fall through
405 case JVM_CONSTANT_Methodref:
406 {
407 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
408 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
409 merge_cp_p, merge_cp_length_p, THREAD);
410
411 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
412 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
413 merge_cp_p, merge_cp_length_p, THREAD);
414
415 const char *entry_name = NULL;
416 switch (scratch_cp->tag_at(scratch_i).value()) {
417 case JVM_CONSTANT_Fieldref:
418 entry_name = "Fieldref";
419 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
420 new_name_and_type_ref_i);
421 break;
422 case JVM_CONSTANT_InterfaceMethodref:
423 entry_name = "IFMethodref";
424 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
425 new_klass_ref_i, new_name_and_type_ref_i);
426 break;
427 case JVM_CONSTANT_Methodref:
428 entry_name = "Methodref";
429 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
430 new_name_and_type_ref_i);
431 break;
432 default:
433 guarantee(false, "bad switch");
434 break;
435 }
436
437 if (klass_ref_i != new_klass_ref_i) {
438 log_trace(redefine, class, constantpool)
439 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
440 }
441 if (name_and_type_ref_i != new_name_and_type_ref_i) {
442 log_trace(redefine, class, constantpool)
443 ("%s entry@%d name_and_type_index changed: %d to %d",
444 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
445 }
446
447 if (scratch_i != *merge_cp_length_p) {
448 // The new entry in *merge_cp_p is at a different index than
449 // the new entry in scratch_cp so we need to map the index values.
450 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
451 }
452 (*merge_cp_length_p)++;
453 } break;
454
455 // this is an indirect CP entry so it needs special handling
456 case JVM_CONSTANT_MethodType:
457 {
458 int ref_i = scratch_cp->method_type_index_at(scratch_i);
459 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
460 merge_cp_length_p, THREAD);
461 if (new_ref_i != ref_i) {
462 log_trace(redefine, class, constantpool)
463 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
464 }
465 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
466 if (scratch_i != *merge_cp_length_p) {
467 // The new entry in *merge_cp_p is at a different index than
468 // the new entry in scratch_cp so we need to map the index values.
469 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
470 }
471 (*merge_cp_length_p)++;
472 } break;
473
474 // this is an indirect CP entry so it needs special handling
475 case JVM_CONSTANT_MethodHandle:
476 {
477 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
478 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
479 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
480 merge_cp_length_p, THREAD);
481 if (new_ref_i != ref_i) {
482 log_trace(redefine, class, constantpool)
483 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
484 }
485 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
486 if (scratch_i != *merge_cp_length_p) {
487 // The new entry in *merge_cp_p is at a different index than
488 // the new entry in scratch_cp so we need to map the index values.
489 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
490 }
491 (*merge_cp_length_p)++;
492 } break;
493
494 // this is an indirect CP entry so it needs special handling
495 case JVM_CONSTANT_InvokeDynamic:
496 {
497 // Index of the bootstrap specifier in the operands array
498 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
499 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
500 merge_cp_length_p, THREAD);
501 // The bootstrap method NameAndType_info index
502 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
503 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
504 merge_cp_length_p, THREAD);
505 if (new_bs_i != old_bs_i) {
506 log_trace(redefine, class, constantpool)
507 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
508 *merge_cp_length_p, old_bs_i, new_bs_i);
509 }
510 if (new_ref_i != old_ref_i) {
511 log_trace(redefine, class, constantpool)
512 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
513 }
514
515 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
516 if (scratch_i != *merge_cp_length_p) {
517 // The new entry in *merge_cp_p is at a different index than
518 // the new entry in scratch_cp so we need to map the index values.
519 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
520 }
521 (*merge_cp_length_p)++;
522 } break;
523
524 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
525 // ClassIndex
526 case JVM_CONSTANT_ClassIndex: // fall through
527
528 // Invalid is used as the tag for the second constant pool entry
529 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
530 // not be seen by itself.
531 case JVM_CONSTANT_Invalid: // fall through
532
533 // At this stage, String could be here, but not StringIndex
534 case JVM_CONSTANT_StringIndex: // fall through
535
536 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
537 // here
538 case JVM_CONSTANT_UnresolvedClassInError: // fall through
539
540 default:
541 {
542 // leave a breadcrumb
543 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
544 ShouldNotReachHere();
545 } break;
546 } // end switch tag value
547 } // end append_entry()
548
549
550 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
551 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
552
553 int new_ref_i = ref_i;
554 bool match = (ref_i < *merge_cp_length_p) &&
555 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
556
557 if (!match) {
558 // forward reference in *merge_cp_p or not a direct match
559 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
560 if (found_i != 0) {
561 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
562 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
563 new_ref_i = found_i;
564 map_index(scratch_cp, ref_i, found_i);
565 } else {
566 // no match found so we have to append this entry to *merge_cp_p
567 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
568 // The above call to append_entry() can only append one entry
569 // so the post call query of *merge_cp_length_p is only for
570 // the sake of consistency.
571 new_ref_i = *merge_cp_length_p - 1;
572 }
573 }
574
575 return new_ref_i;
576 } // end find_or_append_indirect_entry()
577
578
579 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
580 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
581 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
582 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
583 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
584
585 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
586 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
587 merge_cp_length_p, THREAD);
588 if (new_ref_i != old_ref_i) {
589 log_trace(redefine, class, constantpool)
590 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
591 }
592
593 Array<u2>* merge_ops = (*merge_cp_p)->operands();
594 int new_bs_i = _operands_cur_length;
595 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
596 // However, the operand_offset_at(0) was set in the extend_operands() call.
597 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
598 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
599 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
600
601 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
602 merge_ops->at_put(new_base++, new_ref_i);
603 merge_ops->at_put(new_base++, argc);
604
605 for (int i = 0; i < argc; i++) {
606 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
607 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
608 merge_cp_length_p, THREAD);
609 merge_ops->at_put(new_base++, new_arg_ref_i);
610 if (new_arg_ref_i != old_arg_ref_i) {
611 log_trace(redefine, class, constantpool)
612 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
613 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
614 }
615 }
616 if (old_bs_i != _operands_cur_length) {
617 // The bootstrap specifier in *merge_cp_p is at a different index than
618 // that in scratch_cp so we need to map the index values.
619 map_operand_index(old_bs_i, new_bs_i);
620 }
621 _operands_cur_length++;
622 } // end append_operand()
623
624
625 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
626 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
627
628 int new_bs_i = old_bs_i; // bootstrap specifier index
629 bool match = (old_bs_i < _operands_cur_length) &&
630 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
631
632 if (!match) {
633 // forward reference in *merge_cp_p or not a direct match
634 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
635 _operands_cur_length, THREAD);
636 if (found_i != -1) {
637 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
638 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
639 new_bs_i = found_i;
640 map_operand_index(old_bs_i, found_i);
641 } else {
642 // no match found so we have to append this bootstrap specifier to *merge_cp_p
643 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
644 new_bs_i = _operands_cur_length - 1;
645 }
646 }
647 return new_bs_i;
648 } // end find_or_append_operand()
649
650
651 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
652 if (merge_cp->operands() == NULL) {
653 return;
654 }
655 // Shrink the merge_cp operands
656 merge_cp->shrink_operands(_operands_cur_length, CHECK);
657
658 if (log_is_enabled(Trace, redefine, class, constantpool)) {
659 // don't want to loop unless we are tracing
660 int count = 0;
661 for (int i = 1; i < _operands_index_map_p->length(); i++) {
662 int value = _operands_index_map_p->at(i);
663 if (value != -1) {
664 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
665 count++;
666 }
667 }
668 }
669 // Clean-up
670 _operands_index_map_p = NULL;
671 _operands_cur_length = 0;
672 _operands_index_map_count = 0;
673 } // end finalize_operands_merge()
674
675
676 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
677 InstanceKlass* the_class,
678 InstanceKlass* scratch_class) {
679 int i;
680
681 // Check superclasses, or rather their names, since superclasses themselves can be
682 // requested to replace.
683 // Check for NULL superclass first since this might be java.lang.Object
684 if (the_class->super() != scratch_class->super() &&
685 (the_class->super() == NULL || scratch_class->super() == NULL ||
686 the_class->super()->name() !=
687 scratch_class->super()->name())) {
688 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
689 }
690
691 // Check if the number, names and order of directly implemented interfaces are the same.
692 // I think in principle we should just check if the sets of names of directly implemented
693 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
694 // .java file, also changes in .class file) should not matter. However, comparing sets is
695 // technically a bit more difficult, and, more importantly, I am not sure at present that the
696 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
697 // rely on it somewhere.
698 Array<Klass*>* k_interfaces = the_class->local_interfaces();
699 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
700 int n_intfs = k_interfaces->length();
701 if (n_intfs != k_new_interfaces->length()) {
702 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
703 }
704 for (i = 0; i < n_intfs; i++) {
705 if (k_interfaces->at(i)->name() !=
706 k_new_interfaces->at(i)->name()) {
707 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
708 }
709 }
710
711 // Check whether class is in the error init state.
712 if (the_class->is_in_error_state()) {
713 // TBD #5057930: special error code is needed in 1.6
714 return JVMTI_ERROR_INVALID_CLASS;
715 }
716
717 // Check whether class modifiers are the same.
718 jushort old_flags = (jushort) the_class->access_flags().get_flags();
719 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
720 if (old_flags != new_flags) {
721 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
722 }
723
724 // Check if the number, names, types and order of fields declared in these classes
725 // are the same.
726 JavaFieldStream old_fs(the_class);
727 JavaFieldStream new_fs(scratch_class);
728 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
729 // access
730 old_flags = old_fs.access_flags().as_short();
731 new_flags = new_fs.access_flags().as_short();
732 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
733 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
734 }
735 // offset
736 if (old_fs.offset() != new_fs.offset()) {
737 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
738 }
739 // name and signature
740 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
741 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
742 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
743 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
744 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
745 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
746 }
747 }
748
749 // If both streams aren't done then we have a differing number of
750 // fields.
751 if (!old_fs.done() || !new_fs.done()) {
752 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
753 }
754
755 // Do a parallel walk through the old and new methods. Detect
756 // cases where they match (exist in both), have been added in
757 // the new methods, or have been deleted (exist only in the
758 // old methods). The class file parser places methods in order
759 // by method name, but does not order overloaded methods by
760 // signature. In order to determine what fate befell the methods,
761 // this code places the overloaded new methods that have matching
762 // old methods in the same order as the old methods and places
763 // new overloaded methods at the end of overloaded methods of
764 // that name. The code for this order normalization is adapted
765 // from the algorithm used in InstanceKlass::find_method().
766 // Since we are swapping out of order entries as we find them,
767 // we only have to search forward through the overloaded methods.
768 // Methods which are added and have the same name as an existing
769 // method (but different signature) will be put at the end of
770 // the methods with that name, and the name mismatch code will
771 // handle them.
772 Array<Method*>* k_old_methods(the_class->methods());
773 Array<Method*>* k_new_methods(scratch_class->methods());
774 int n_old_methods = k_old_methods->length();
775 int n_new_methods = k_new_methods->length();
776 Thread* thread = Thread::current();
777
778 int ni = 0;
779 int oi = 0;
780 while (true) {
781 Method* k_old_method;
782 Method* k_new_method;
783 enum { matched, added, deleted, undetermined } method_was = undetermined;
784
785 if (oi >= n_old_methods) {
786 if (ni >= n_new_methods) {
787 break; // we've looked at everything, done
788 }
789 // New method at the end
790 k_new_method = k_new_methods->at(ni);
791 method_was = added;
792 } else if (ni >= n_new_methods) {
793 // Old method, at the end, is deleted
794 k_old_method = k_old_methods->at(oi);
795 method_was = deleted;
796 } else {
797 // There are more methods in both the old and new lists
798 k_old_method = k_old_methods->at(oi);
799 k_new_method = k_new_methods->at(ni);
800 if (k_old_method->name() != k_new_method->name()) {
801 // Methods are sorted by method name, so a mismatch means added
802 // or deleted
803 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
804 method_was = added;
805 } else {
806 method_was = deleted;
807 }
808 } else if (k_old_method->signature() == k_new_method->signature()) {
809 // Both the name and signature match
810 method_was = matched;
811 } else {
812 // The name matches, but the signature doesn't, which means we have to
813 // search forward through the new overloaded methods.
814 int nj; // outside the loop for post-loop check
815 for (nj = ni + 1; nj < n_new_methods; nj++) {
816 Method* m = k_new_methods->at(nj);
817 if (k_old_method->name() != m->name()) {
818 // reached another method name so no more overloaded methods
819 method_was = deleted;
820 break;
821 }
822 if (k_old_method->signature() == m->signature()) {
823 // found a match so swap the methods
824 k_new_methods->at_put(ni, m);
825 k_new_methods->at_put(nj, k_new_method);
826 k_new_method = m;
827 method_was = matched;
828 break;
829 }
830 }
831
832 if (nj >= n_new_methods) {
833 // reached the end without a match; so method was deleted
834 method_was = deleted;
835 }
836 }
837 }
838
839 switch (method_was) {
840 case matched:
841 // methods match, be sure modifiers do too
842 old_flags = (jushort) k_old_method->access_flags().get_flags();
843 new_flags = (jushort) k_new_method->access_flags().get_flags();
844 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
845 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
846 }
847 {
848 u2 new_num = k_new_method->method_idnum();
849 u2 old_num = k_old_method->method_idnum();
850 if (new_num != old_num) {
851 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
852 if (idnum_owner != NULL) {
853 // There is already a method assigned this idnum -- switch them
854 // Take current and original idnum from the new_method
855 idnum_owner->set_method_idnum(new_num);
856 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
857 }
858 // Take current and original idnum from the old_method
859 k_new_method->set_method_idnum(old_num);
860 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
861 if (thread->has_pending_exception()) {
862 return JVMTI_ERROR_OUT_OF_MEMORY;
863 }
864 }
865 }
866 log_trace(redefine, class, normalize)
867 ("Method matched: new: %s [%d] == old: %s [%d]",
868 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
869 // advance to next pair of methods
870 ++oi;
871 ++ni;
872 break;
873 case added:
874 // method added, see if it is OK
875 new_flags = (jushort) k_new_method->access_flags().get_flags();
876 if ((new_flags & JVM_ACC_PRIVATE) == 0
877 // hack: private should be treated as final, but alas
878 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
879 ) {
880 // new methods must be private
881 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
882 }
883 {
884 u2 num = the_class->next_method_idnum();
885 if (num == ConstMethod::UNSET_IDNUM) {
886 // cannot add any more methods
887 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
888 }
889 u2 new_num = k_new_method->method_idnum();
890 Method* idnum_owner = scratch_class->method_with_idnum(num);
891 if (idnum_owner != NULL) {
892 // There is already a method assigned this idnum -- switch them
893 // Take current and original idnum from the new_method
894 idnum_owner->set_method_idnum(new_num);
895 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
896 }
897 k_new_method->set_method_idnum(num);
898 k_new_method->set_orig_method_idnum(num);
899 if (thread->has_pending_exception()) {
900 return JVMTI_ERROR_OUT_OF_MEMORY;
901 }
902 }
903 log_trace(redefine, class, normalize)
904 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
905 ++ni; // advance to next new method
906 break;
907 case deleted:
908 // method deleted, see if it is OK
909 old_flags = (jushort) k_old_method->access_flags().get_flags();
910 if ((old_flags & JVM_ACC_PRIVATE) == 0
911 // hack: private should be treated as final, but alas
912 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
913 ) {
914 // deleted methods must be private
915 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
916 }
917 log_trace(redefine, class, normalize)
918 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
919 ++oi; // advance to next old method
920 break;
921 default:
922 ShouldNotReachHere();
923 }
924 }
925
926 return JVMTI_ERROR_NONE;
927 }
928
929
930 // Find new constant pool index value for old constant pool index value
931 // by seaching the index map. Returns zero (0) if there is no mapped
932 // value for the old constant pool index.
933 int VM_RedefineClasses::find_new_index(int old_index) {
934 if (_index_map_count == 0) {
935 // map is empty so nothing can be found
936 return 0;
937 }
938
939 if (old_index < 1 || old_index >= _index_map_p->length()) {
940 // The old_index is out of range so it is not mapped. This should
941 // not happen in regular constant pool merging use, but it can
942 // happen if a corrupt annotation is processed.
943 return 0;
944 }
945
946 int value = _index_map_p->at(old_index);
947 if (value == -1) {
948 // the old_index is not mapped
949 return 0;
950 }
951
952 return value;
953 } // end find_new_index()
954
955
956 // Find new bootstrap specifier index value for old bootstrap specifier index
957 // value by seaching the index map. Returns unused index (-1) if there is
958 // no mapped value for the old bootstrap specifier index.
959 int VM_RedefineClasses::find_new_operand_index(int old_index) {
960 if (_operands_index_map_count == 0) {
961 // map is empty so nothing can be found
962 return -1;
963 }
964
965 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
966 // The old_index is out of range so it is not mapped.
967 // This should not happen in regular constant pool merging use.
968 return -1;
969 }
970
971 int value = _operands_index_map_p->at(old_index);
972 if (value == -1) {
973 // the old_index is not mapped
974 return -1;
975 }
976
977 return value;
978 } // end find_new_operand_index()
979
980
981 // Returns true if the current mismatch is due to a resolved/unresolved
982 // class pair. Otherwise, returns false.
983 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
984 int index1, const constantPoolHandle& cp2, int index2) {
985
986 jbyte t1 = cp1->tag_at(index1).value();
987 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
988 return false; // wrong entry type; not our special case
989 }
990
991 jbyte t2 = cp2->tag_at(index2).value();
992 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
993 return false; // wrong entry type; not our special case
994 }
995
996 if (t1 == t2) {
997 return false; // not a mismatch; not our special case
998 }
999
1000 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1001 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1002 if (strcmp(s1, s2) != 0) {
1003 return false; // strings don't match; not our special case
1004 }
1005
1006 return true; // made it through the gauntlet; this is our special case
1007 } // end is_unresolved_class_mismatch()
1008
1009
1010 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1011
1012 // For consistency allocate memory using os::malloc wrapper.
1013 _scratch_classes = (InstanceKlass**)
1014 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1015 if (_scratch_classes == NULL) {
1016 return JVMTI_ERROR_OUT_OF_MEMORY;
1017 }
1018 // Zero initialize the _scratch_classes array.
1019 for (int i = 0; i < _class_count; i++) {
1020 _scratch_classes[i] = NULL;
1021 }
1022
1023 ResourceMark rm(THREAD);
1024
1025 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1026 // state can only be NULL if the current thread is exiting which
1027 // should not happen since we're trying to do a RedefineClasses
1028 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1029 for (int i = 0; i < _class_count; i++) {
1030 // Create HandleMark so that any handles created while loading new class
1031 // versions are deleted. Constant pools are deallocated while merging
1032 // constant pools
1033 HandleMark hm(THREAD);
1034 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1035 Symbol* the_class_sym = the_class->name();
1036
1037 log_debug(redefine, class, load)
1038 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1039 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1040
1041 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1042 _class_defs[i].class_byte_count,
1043 "__VM_RedefineClasses__",
1044 ClassFileStream::verify);
1045
1046 // Parse the stream.
1047 Handle the_class_loader(THREAD, the_class->class_loader());
1048 Handle protection_domain(THREAD, the_class->protection_domain());
1049 // Set redefined class handle in JvmtiThreadState class.
1050 // This redefined class is sent to agent event handler for class file
1051 // load hook event.
1052 state->set_class_being_redefined(the_class, _class_load_kind);
1053
1054 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1055 the_class_sym,
1056 the_class_loader,
1057 protection_domain,
1058 &st,
1059 THREAD);
1060 // Clear class_being_redefined just to be sure.
1061 state->clear_class_being_redefined();
1062
1063 // TODO: if this is retransform, and nothing changed we can skip it
1064
1065 // Need to clean up allocated InstanceKlass if there's an error so assign
1066 // the result here. Caller deallocates all the scratch classes in case of
1067 // an error.
1068 _scratch_classes[i] = scratch_class;
1069
1070 if (HAS_PENDING_EXCEPTION) {
1071 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1072 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1073 CLEAR_PENDING_EXCEPTION;
1074
1075 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1076 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1077 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1078 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1079 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1080 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1081 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1082 // The message will be "XXX (wrong name: YYY)"
1083 return JVMTI_ERROR_NAMES_DONT_MATCH;
1084 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1085 return JVMTI_ERROR_OUT_OF_MEMORY;
1086 } else { // Just in case more exceptions can be thrown..
1087 return JVMTI_ERROR_FAILS_VERIFICATION;
1088 }
1089 }
1090
1091 // Ensure class is linked before redefine
1092 if (!the_class->is_linked()) {
1093 the_class->link_class(THREAD);
1094 if (HAS_PENDING_EXCEPTION) {
1095 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1096 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1097 CLEAR_PENDING_EXCEPTION;
1098 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1099 return JVMTI_ERROR_OUT_OF_MEMORY;
1100 } else {
1101 return JVMTI_ERROR_INTERNAL;
1102 }
1103 }
1104 }
1105
1106 // Do the validity checks in compare_and_normalize_class_versions()
1107 // before verifying the byte codes. By doing these checks first, we
1108 // limit the number of functions that require redirection from
1109 // the_class to scratch_class. In particular, we don't have to
1110 // modify JNI GetSuperclass() and thus won't change its performance.
1111 jvmtiError res = compare_and_normalize_class_versions(the_class,
1112 scratch_class);
1113 if (res != JVMTI_ERROR_NONE) {
1114 return res;
1115 }
1116
1117 // verify what the caller passed us
1118 {
1119 // The bug 6214132 caused the verification to fail.
1120 // Information about the_class and scratch_class is temporarily
1121 // recorded into jvmtiThreadState. This data is used to redirect
1122 // the_class to scratch_class in the JVM_* functions called by the
1123 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1124 // description.
1125 RedefineVerifyMark rvm(the_class, scratch_class, state);
1126 Verifier::verify(
1127 scratch_class, Verifier::ThrowException, true, THREAD);
1128 }
1129
1130 if (HAS_PENDING_EXCEPTION) {
1131 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1132 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1133 CLEAR_PENDING_EXCEPTION;
1134 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1135 return JVMTI_ERROR_OUT_OF_MEMORY;
1136 } else {
1137 // tell the caller the bytecodes are bad
1138 return JVMTI_ERROR_FAILS_VERIFICATION;
1139 }
1140 }
1141
1142 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1143 if (HAS_PENDING_EXCEPTION) {
1144 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1145 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1146 CLEAR_PENDING_EXCEPTION;
1147 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1148 return JVMTI_ERROR_OUT_OF_MEMORY;
1149 } else {
1150 return JVMTI_ERROR_INTERNAL;
1151 }
1152 }
1153
1154 if (VerifyMergedCPBytecodes) {
1155 // verify what we have done during constant pool merging
1156 {
1157 RedefineVerifyMark rvm(the_class, scratch_class, state);
1158 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1159 }
1160
1161 if (HAS_PENDING_EXCEPTION) {
1162 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1163 log_info(redefine, class, load, exceptions)
1164 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1165 CLEAR_PENDING_EXCEPTION;
1166 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1167 return JVMTI_ERROR_OUT_OF_MEMORY;
1168 } else {
1169 // tell the caller that constant pool merging screwed up
1170 return JVMTI_ERROR_INTERNAL;
1171 }
1172 }
1173 }
1174
1175 Rewriter::rewrite(scratch_class, THREAD);
1176 if (!HAS_PENDING_EXCEPTION) {
1177 scratch_class->link_methods(THREAD);
1178 }
1179 if (HAS_PENDING_EXCEPTION) {
1180 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1181 log_info(redefine, class, load, exceptions)
1182 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1183 CLEAR_PENDING_EXCEPTION;
1184 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1185 return JVMTI_ERROR_OUT_OF_MEMORY;
1186 } else {
1187 return JVMTI_ERROR_INTERNAL;
1188 }
1189 }
1190
1191 log_debug(redefine, class, load)
1192 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1193 }
1194
1195 return JVMTI_ERROR_NONE;
1196 }
1197
1198
1199 // Map old_index to new_index as needed. scratch_cp is only needed
1200 // for log calls.
1201 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1202 int old_index, int new_index) {
1203 if (find_new_index(old_index) != 0) {
1204 // old_index is already mapped
1205 return;
1206 }
1207
1208 if (old_index == new_index) {
1209 // no mapping is needed
1210 return;
1211 }
1212
1213 _index_map_p->at_put(old_index, new_index);
1214 _index_map_count++;
1215
1216 log_trace(redefine, class, constantpool)
1217 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1218 } // end map_index()
1219
1220
1221 // Map old_index to new_index as needed.
1222 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1223 if (find_new_operand_index(old_index) != -1) {
1224 // old_index is already mapped
1225 return;
1226 }
1227
1228 if (old_index == new_index) {
1229 // no mapping is needed
1230 return;
1231 }
1232
1233 _operands_index_map_p->at_put(old_index, new_index);
1234 _operands_index_map_count++;
1235
1236 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1237 } // end map_index()
1238
1239
1240 // Merge old_cp and scratch_cp and return the results of the merge via
1241 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1242 // merge_cp_length_p. The entries in old_cp occupy the same locations
1243 // in *merge_cp_p. Also creates a map of indices from entries in
1244 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1245 // entries are only created for entries in scratch_cp that occupy a
1246 // different location in *merged_cp_p.
1247 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1248 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1249 int *merge_cp_length_p, TRAPS) {
1250
1251 if (merge_cp_p == NULL) {
1252 assert(false, "caller must provide scratch constantPool");
1253 return false; // robustness
1254 }
1255 if (merge_cp_length_p == NULL) {
1256 assert(false, "caller must provide scratch CP length");
1257 return false; // robustness
1258 }
1259 // Worst case we need old_cp->length() + scratch_cp()->length(),
1260 // but the caller might be smart so make sure we have at least
1261 // the minimum.
1262 if ((*merge_cp_p)->length() < old_cp->length()) {
1263 assert(false, "merge area too small");
1264 return false; // robustness
1265 }
1266
1267 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1268
1269 {
1270 // Pass 0:
1271 // The old_cp is copied to *merge_cp_p; this means that any code
1272 // using old_cp does not have to change. This work looks like a
1273 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1274 // handle one special case:
1275 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1276 // This will make verification happy.
1277
1278 int old_i; // index into old_cp
1279
1280 // index zero (0) is not used in constantPools
1281 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1282 // leave debugging crumb
1283 jbyte old_tag = old_cp->tag_at(old_i).value();
1284 switch (old_tag) {
1285 case JVM_CONSTANT_Class:
1286 case JVM_CONSTANT_UnresolvedClass:
1287 // revert the copy to JVM_CONSTANT_UnresolvedClass
1288 // May be resolving while calling this so do the same for
1289 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1290 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1291 old_cp->klass_name_index_at(old_i));
1292 break;
1293
1294 case JVM_CONSTANT_Double:
1295 case JVM_CONSTANT_Long:
1296 // just copy the entry to *merge_cp_p, but double and long take
1297 // two constant pool entries
1298 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1299 old_i++;
1300 break;
1301
1302 default:
1303 // just copy the entry to *merge_cp_p
1304 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1305 break;
1306 }
1307 } // end for each old_cp entry
1308
1309 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1310 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1311
1312 // We don't need to sanity check that *merge_cp_length_p is within
1313 // *merge_cp_p bounds since we have the minimum on-entry check above.
1314 (*merge_cp_length_p) = old_i;
1315 }
1316
1317 // merge_cp_len should be the same as old_cp->length() at this point
1318 // so this trace message is really a "warm-and-breathing" message.
1319 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1320
1321 int scratch_i; // index into scratch_cp
1322 {
1323 // Pass 1a:
1324 // Compare scratch_cp entries to the old_cp entries that we have
1325 // already copied to *merge_cp_p. In this pass, we are eliminating
1326 // exact duplicates (matching entry at same index) so we only
1327 // compare entries in the common indice range.
1328 int increment = 1;
1329 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1330 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1331 switch (scratch_cp->tag_at(scratch_i).value()) {
1332 case JVM_CONSTANT_Double:
1333 case JVM_CONSTANT_Long:
1334 // double and long take two constant pool entries
1335 increment = 2;
1336 break;
1337
1338 default:
1339 increment = 1;
1340 break;
1341 }
1342
1343 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1344 scratch_i, CHECK_0);
1345 if (match) {
1346 // found a match at the same index so nothing more to do
1347 continue;
1348 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1349 *merge_cp_p, scratch_i)) {
1350 // The mismatch in compare_entry_to() above is because of a
1351 // resolved versus unresolved class entry at the same index
1352 // with the same string value. Since Pass 0 reverted any
1353 // class entries to unresolved class entries in *merge_cp_p,
1354 // we go with the unresolved class entry.
1355 continue;
1356 }
1357
1358 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1359 CHECK_0);
1360 if (found_i != 0) {
1361 guarantee(found_i != scratch_i,
1362 "compare_entry_to() and find_matching_entry() do not agree");
1363
1364 // Found a matching entry somewhere else in *merge_cp_p so
1365 // just need a mapping entry.
1366 map_index(scratch_cp, scratch_i, found_i);
1367 continue;
1368 }
1369
1370 // The find_matching_entry() call above could fail to find a match
1371 // due to a resolved versus unresolved class or string entry situation
1372 // like we solved above with the is_unresolved_*_mismatch() calls.
1373 // However, we would have to call is_unresolved_*_mismatch() over
1374 // all of *merge_cp_p (potentially) and that doesn't seem to be
1375 // worth the time.
1376
1377 // No match found so we have to append this entry and any unique
1378 // referenced entries to *merge_cp_p.
1379 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1380 CHECK_0);
1381 }
1382 }
1383
1384 log_debug(redefine, class, constantpool)
1385 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1386 *merge_cp_length_p, scratch_i, _index_map_count);
1387
1388 if (scratch_i < scratch_cp->length()) {
1389 // Pass 1b:
1390 // old_cp is smaller than scratch_cp so there are entries in
1391 // scratch_cp that we have not yet processed. We take care of
1392 // those now.
1393 int increment = 1;
1394 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1395 switch (scratch_cp->tag_at(scratch_i).value()) {
1396 case JVM_CONSTANT_Double:
1397 case JVM_CONSTANT_Long:
1398 // double and long take two constant pool entries
1399 increment = 2;
1400 break;
1401
1402 default:
1403 increment = 1;
1404 break;
1405 }
1406
1407 int found_i =
1408 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1409 if (found_i != 0) {
1410 // Found a matching entry somewhere else in *merge_cp_p so
1411 // just need a mapping entry.
1412 map_index(scratch_cp, scratch_i, found_i);
1413 continue;
1414 }
1415
1416 // No match found so we have to append this entry and any unique
1417 // referenced entries to *merge_cp_p.
1418 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1419 CHECK_0);
1420 }
1421
1422 log_debug(redefine, class, constantpool)
1423 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1424 *merge_cp_length_p, scratch_i, _index_map_count);
1425 }
1426 finalize_operands_merge(*merge_cp_p, THREAD);
1427
1428 return true;
1429 } // end merge_constant_pools()
1430
1431
1432 // Scoped object to clean up the constant pool(s) created for merging
1433 class MergeCPCleaner {
1434 ClassLoaderData* _loader_data;
1435 ConstantPool* _cp;
1436 ConstantPool* _scratch_cp;
1437 public:
1438 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1439 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1440 ~MergeCPCleaner() {
1441 _loader_data->add_to_deallocate_list(_cp);
1442 if (_scratch_cp != NULL) {
1443 _loader_data->add_to_deallocate_list(_scratch_cp);
1444 }
1445 }
1446 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1447 };
1448
1449 // Merge constant pools between the_class and scratch_class and
1450 // potentially rewrite bytecodes in scratch_class to use the merged
1451 // constant pool.
1452 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1453 InstanceKlass* the_class, InstanceKlass* scratch_class,
1454 TRAPS) {
1455 // worst case merged constant pool length is old and new combined
1456 int merge_cp_length = the_class->constants()->length()
1457 + scratch_class->constants()->length();
1458
1459 // Constant pools are not easily reused so we allocate a new one
1460 // each time.
1461 // merge_cp is created unsafe for concurrent GC processing. It
1462 // should be marked safe before discarding it. Even though
1463 // garbage, if it crosses a card boundary, it may be scanned
1464 // in order to find the start of the first complete object on the card.
1465 ClassLoaderData* loader_data = the_class->class_loader_data();
1466 ConstantPool* merge_cp_oop =
1467 ConstantPool::allocate(loader_data,
1468 merge_cp_length,
1469 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1470 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1471
1472 HandleMark hm(THREAD); // make sure handles are cleared before
1473 // MergeCPCleaner clears out merge_cp_oop
1474 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1475
1476 // Get constants() from the old class because it could have been rewritten
1477 // while we were at a safepoint allocating a new constant pool.
1478 constantPoolHandle old_cp(THREAD, the_class->constants());
1479 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1480
1481 // If the length changed, the class was redefined out from under us. Return
1482 // an error.
1483 if (merge_cp_length != the_class->constants()->length()
1484 + scratch_class->constants()->length()) {
1485 return JVMTI_ERROR_INTERNAL;
1486 }
1487
1488 // Update the version number of the constant pools (may keep scratch_cp)
1489 merge_cp->increment_and_save_version(old_cp->version());
1490 scratch_cp->increment_and_save_version(old_cp->version());
1491
1492 ResourceMark rm(THREAD);
1493 _index_map_count = 0;
1494 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1495
1496 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1497 _operands_index_map_count = 0;
1498 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1499 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1500
1501 // reference to the cp holder is needed for copy_operands()
1502 merge_cp->set_pool_holder(scratch_class);
1503 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1504 &merge_cp_length, THREAD);
1505 merge_cp->set_pool_holder(NULL);
1506
1507 if (!result) {
1508 // The merge can fail due to memory allocation failure or due
1509 // to robustness checks.
1510 return JVMTI_ERROR_INTERNAL;
1511 }
1512
1513 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1514
1515 if (_index_map_count == 0) {
1516 // there is nothing to map between the new and merged constant pools
1517
1518 if (old_cp->length() == scratch_cp->length()) {
1519 // The old and new constant pools are the same length and the
1520 // index map is empty. This means that the three constant pools
1521 // are equivalent (but not the same). Unfortunately, the new
1522 // constant pool has not gone through link resolution nor have
1523 // the new class bytecodes gone through constant pool cache
1524 // rewriting so we can't use the old constant pool with the new
1525 // class.
1526
1527 // toss the merged constant pool at return
1528 } else if (old_cp->length() < scratch_cp->length()) {
1529 // The old constant pool has fewer entries than the new constant
1530 // pool and the index map is empty. This means the new constant
1531 // pool is a superset of the old constant pool. However, the old
1532 // class bytecodes have already gone through constant pool cache
1533 // rewriting so we can't use the new constant pool with the old
1534 // class.
1535
1536 // toss the merged constant pool at return
1537 } else {
1538 // The old constant pool has more entries than the new constant
1539 // pool and the index map is empty. This means that both the old
1540 // and merged constant pools are supersets of the new constant
1541 // pool.
1542
1543 // Replace the new constant pool with a shrunken copy of the
1544 // merged constant pool
1545 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1546 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1547 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1548 // It can't be cleaned up while there are handles to it.
1549 cp_cleaner.add_scratch_cp(scratch_cp());
1550 }
1551 } else {
1552 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1553 // don't want to loop unless we are tracing
1554 int count = 0;
1555 for (int i = 1; i < _index_map_p->length(); i++) {
1556 int value = _index_map_p->at(i);
1557
1558 if (value != -1) {
1559 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1560 count++;
1561 }
1562 }
1563 }
1564
1565 // We have entries mapped between the new and merged constant pools
1566 // so we have to rewrite some constant pool references.
1567 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1568 return JVMTI_ERROR_INTERNAL;
1569 }
1570
1571 // Replace the new constant pool with a shrunken copy of the
1572 // merged constant pool so now the rewritten bytecodes have
1573 // valid references; the previous new constant pool will get
1574 // GCed.
1575 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1576 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1577 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1578 // It can't be cleaned up while there are handles to it.
1579 cp_cleaner.add_scratch_cp(scratch_cp());
1580 }
1581
1582 return JVMTI_ERROR_NONE;
1583 } // end merge_cp_and_rewrite()
1584
1585
1586 // Rewrite constant pool references in klass scratch_class.
1587 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1588 TRAPS) {
1589
1590 // rewrite constant pool references in the methods:
1591 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1592 // propagate failure back to caller
1593 return false;
1594 }
1595
1596 // rewrite constant pool references in the class_annotations:
1597 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1598 // propagate failure back to caller
1599 return false;
1600 }
1601
1602 // rewrite constant pool references in the fields_annotations:
1603 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1604 // propagate failure back to caller
1605 return false;
1606 }
1607
1608 // rewrite constant pool references in the methods_annotations:
1609 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1610 // propagate failure back to caller
1611 return false;
1612 }
1613
1614 // rewrite constant pool references in the methods_parameter_annotations:
1615 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1616 THREAD)) {
1617 // propagate failure back to caller
1618 return false;
1619 }
1620
1621 // rewrite constant pool references in the methods_default_annotations:
1622 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1623 THREAD)) {
1624 // propagate failure back to caller
1625 return false;
1626 }
1627
1628 // rewrite constant pool references in the class_type_annotations:
1629 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1630 // propagate failure back to caller
1631 return false;
1632 }
1633
1634 // rewrite constant pool references in the fields_type_annotations:
1635 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1636 // propagate failure back to caller
1637 return false;
1638 }
1639
1640 // rewrite constant pool references in the methods_type_annotations:
1641 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1642 // propagate failure back to caller
1643 return false;
1644 }
1645
1646 // There can be type annotations in the Code part of a method_info attribute.
1647 // These annotations are not accessible, even by reflection.
1648 // Currently they are not even parsed by the ClassFileParser.
1649 // If runtime access is added they will also need to be rewritten.
1650
1651 // rewrite source file name index:
1652 u2 source_file_name_idx = scratch_class->source_file_name_index();
1653 if (source_file_name_idx != 0) {
1654 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1655 if (new_source_file_name_idx != 0) {
1656 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1657 }
1658 }
1659
1660 // rewrite class generic signature index:
1661 u2 generic_signature_index = scratch_class->generic_signature_index();
1662 if (generic_signature_index != 0) {
1663 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1664 if (new_generic_signature_index != 0) {
1665 scratch_class->set_generic_signature_index(new_generic_signature_index);
1666 }
1667 }
1668
1669 return true;
1670 } // end rewrite_cp_refs()
1671
1672 // Rewrite constant pool references in the methods.
1673 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1674 InstanceKlass* scratch_class, TRAPS) {
1675
1676 Array<Method*>* methods = scratch_class->methods();
1677
1678 if (methods == NULL || methods->length() == 0) {
1679 // no methods so nothing to do
1680 return true;
1681 }
1682
1683 // rewrite constant pool references in the methods:
1684 for (int i = methods->length() - 1; i >= 0; i--) {
1685 methodHandle method(THREAD, methods->at(i));
1686 methodHandle new_method;
1687 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1688 if (!new_method.is_null()) {
1689 // the method has been replaced so save the new method version
1690 // even in the case of an exception. original method is on the
1691 // deallocation list.
1692 methods->at_put(i, new_method());
1693 }
1694 if (HAS_PENDING_EXCEPTION) {
1695 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1696 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1697 // Need to clear pending exception here as the super caller sets
1698 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1699 CLEAR_PENDING_EXCEPTION;
1700 return false;
1701 }
1702 }
1703
1704 return true;
1705 }
1706
1707
1708 // Rewrite constant pool references in the specific method. This code
1709 // was adapted from Rewriter::rewrite_method().
1710 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1711 methodHandle *new_method_p, TRAPS) {
1712
1713 *new_method_p = methodHandle(); // default is no new method
1714
1715 // We cache a pointer to the bytecodes here in code_base. If GC
1716 // moves the Method*, then the bytecodes will also move which
1717 // will likely cause a crash. We create a NoSafepointVerifier
1718 // object to detect whether we pass a possible safepoint in this
1719 // code block.
1720 NoSafepointVerifier nsv;
1721
1722 // Bytecodes and their length
1723 address code_base = method->code_base();
1724 int code_length = method->code_size();
1725
1726 int bc_length;
1727 for (int bci = 0; bci < code_length; bci += bc_length) {
1728 address bcp = code_base + bci;
1729 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1730
1731 bc_length = Bytecodes::length_for(c);
1732 if (bc_length == 0) {
1733 // More complicated bytecodes report a length of zero so
1734 // we have to try again a slightly different way.
1735 bc_length = Bytecodes::length_at(method(), bcp);
1736 }
1737
1738 assert(bc_length != 0, "impossible bytecode length");
1739
1740 switch (c) {
1741 case Bytecodes::_ldc:
1742 {
1743 int cp_index = *(bcp + 1);
1744 int new_index = find_new_index(cp_index);
1745
1746 if (StressLdcRewrite && new_index == 0) {
1747 // If we are stressing ldc -> ldc_w rewriting, then we
1748 // always need a new_index value.
1749 new_index = cp_index;
1750 }
1751 if (new_index != 0) {
1752 // the original index is mapped so we have more work to do
1753 if (!StressLdcRewrite && new_index <= max_jubyte) {
1754 // The new value can still use ldc instead of ldc_w
1755 // unless we are trying to stress ldc -> ldc_w rewriting
1756 log_trace(redefine, class, constantpool)
1757 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1758 *(bcp + 1) = new_index;
1759 } else {
1760 log_trace(redefine, class, constantpool)
1761 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1762 // the new value needs ldc_w instead of ldc
1763 u_char inst_buffer[4]; // max instruction size is 4 bytes
1764 bcp = (address)inst_buffer;
1765 // construct new instruction sequence
1766 *bcp = Bytecodes::_ldc_w;
1767 bcp++;
1768 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1769 // See comment below for difference between put_Java_u2()
1770 // and put_native_u2().
1771 Bytes::put_Java_u2(bcp, new_index);
1772
1773 Relocator rc(method, NULL /* no RelocatorListener needed */);
1774 methodHandle m;
1775 {
1776 PauseNoSafepointVerifier pnsv(&nsv);
1777
1778 // ldc is 2 bytes and ldc_w is 3 bytes
1779 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1780 }
1781
1782 // return the new method so that the caller can update
1783 // the containing class
1784 *new_method_p = method = m;
1785 // switch our bytecode processing loop from the old method
1786 // to the new method
1787 code_base = method->code_base();
1788 code_length = method->code_size();
1789 bcp = code_base + bci;
1790 c = (Bytecodes::Code)(*bcp);
1791 bc_length = Bytecodes::length_for(c);
1792 assert(bc_length != 0, "sanity check");
1793 } // end we need ldc_w instead of ldc
1794 } // end if there is a mapped index
1795 } break;
1796
1797 // these bytecodes have a two-byte constant pool index
1798 case Bytecodes::_anewarray : // fall through
1799 case Bytecodes::_checkcast : // fall through
1800 case Bytecodes::_getfield : // fall through
1801 case Bytecodes::_getstatic : // fall through
1802 case Bytecodes::_instanceof : // fall through
1803 case Bytecodes::_invokedynamic : // fall through
1804 case Bytecodes::_invokeinterface: // fall through
1805 case Bytecodes::_invokespecial : // fall through
1806 case Bytecodes::_invokestatic : // fall through
1807 case Bytecodes::_invokevirtual : // fall through
1808 case Bytecodes::_ldc_w : // fall through
1809 case Bytecodes::_ldc2_w : // fall through
1810 case Bytecodes::_multianewarray : // fall through
1811 case Bytecodes::_new : // fall through
1812 case Bytecodes::_putfield : // fall through
1813 case Bytecodes::_putstatic :
1814 {
1815 address p = bcp + 1;
1816 int cp_index = Bytes::get_Java_u2(p);
1817 int new_index = find_new_index(cp_index);
1818 if (new_index != 0) {
1819 // the original index is mapped so update w/ new value
1820 log_trace(redefine, class, constantpool)
1821 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1822 // Rewriter::rewrite_method() uses put_native_u2() in this
1823 // situation because it is reusing the constant pool index
1824 // location for a native index into the ConstantPoolCache.
1825 // Since we are updating the constant pool index prior to
1826 // verification and ConstantPoolCache initialization, we
1827 // need to keep the new index in Java byte order.
1828 Bytes::put_Java_u2(p, new_index);
1829 }
1830 } break;
1831 default:
1832 break;
1833 }
1834 } // end for each bytecode
1835
1836 // We also need to rewrite the parameter name indexes, if there is
1837 // method parameter data present
1838 if(method->has_method_parameters()) {
1839 const int len = method->method_parameters_length();
1840 MethodParametersElement* elem = method->method_parameters_start();
1841
1842 for (int i = 0; i < len; i++) {
1843 const u2 cp_index = elem[i].name_cp_index;
1844 const u2 new_cp_index = find_new_index(cp_index);
1845 if (new_cp_index != 0) {
1846 elem[i].name_cp_index = new_cp_index;
1847 }
1848 }
1849 }
1850 } // end rewrite_cp_refs_in_method()
1851
1852
1853 // Rewrite constant pool references in the class_annotations field.
1854 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1855 InstanceKlass* scratch_class, TRAPS) {
1856
1857 AnnotationArray* class_annotations = scratch_class->class_annotations();
1858 if (class_annotations == NULL || class_annotations->length() == 0) {
1859 // no class_annotations so nothing to do
1860 return true;
1861 }
1862
1863 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1864
1865 int byte_i = 0; // byte index into class_annotations
1866 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1867 THREAD);
1868 }
1869
1870
1871 // Rewrite constant pool references in an annotations typeArray. This
1872 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1873 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1874 //
1875 // annotations_typeArray {
1876 // u2 num_annotations;
1877 // annotation annotations[num_annotations];
1878 // }
1879 //
1880 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1881 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1882
1883 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1884 // not enough room for num_annotations field
1885 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1886 return false;
1887 }
1888
1889 u2 num_annotations = Bytes::get_Java_u2((address)
1890 annotations_typeArray->adr_at(byte_i_ref));
1891 byte_i_ref += 2;
1892
1893 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1894
1895 int calc_num_annotations = 0;
1896 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1897 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1898 byte_i_ref, THREAD)) {
1899 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1900 // propagate failure back to caller
1901 return false;
1902 }
1903 }
1904 assert(num_annotations == calc_num_annotations, "sanity check");
1905
1906 return true;
1907 } // end rewrite_cp_refs_in_annotations_typeArray()
1908
1909
1910 // Rewrite constant pool references in the annotation struct portion of
1911 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1912 // the 2nd-edition of the VM spec:
1913 //
1914 // struct annotation {
1915 // u2 type_index;
1916 // u2 num_element_value_pairs;
1917 // {
1918 // u2 element_name_index;
1919 // element_value value;
1920 // } element_value_pairs[num_element_value_pairs];
1921 // }
1922 //
1923 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1924 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1925 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1926 // not enough room for smallest annotation_struct
1927 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1928 return false;
1929 }
1930
1931 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1932 byte_i_ref, "type_index", THREAD);
1933
1934 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1935 annotations_typeArray->adr_at(byte_i_ref));
1936 byte_i_ref += 2;
1937
1938 log_debug(redefine, class, annotation)
1939 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1940
1941 int calc_num_element_value_pairs = 0;
1942 for (; calc_num_element_value_pairs < num_element_value_pairs;
1943 calc_num_element_value_pairs++) {
1944 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1945 // not enough room for another element_name_index, let alone
1946 // the rest of another component
1947 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1948 return false;
1949 }
1950
1951 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1952 annotations_typeArray, byte_i_ref,
1953 "element_name_index", THREAD);
1954
1955 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1956
1957 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1958 byte_i_ref, THREAD)) {
1959 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1960 // propagate failure back to caller
1961 return false;
1962 }
1963 } // end for each component
1964 assert(num_element_value_pairs == calc_num_element_value_pairs,
1965 "sanity check");
1966
1967 return true;
1968 } // end rewrite_cp_refs_in_annotation_struct()
1969
1970
1971 // Rewrite a constant pool reference at the current position in
1972 // annotations_typeArray if needed. Returns the original constant
1973 // pool reference if a rewrite was not needed or the new constant
1974 // pool reference if a rewrite was needed.
1975 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1976 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1977 const char * trace_mesg, TRAPS) {
1978
1979 address cp_index_addr = (address)
1980 annotations_typeArray->adr_at(byte_i_ref);
1981 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1982 u2 new_cp_index = find_new_index(old_cp_index);
1983 if (new_cp_index != 0) {
1984 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1985 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1986 old_cp_index = new_cp_index;
1987 }
1988 byte_i_ref += 2;
1989 return old_cp_index;
1990 }
1991
1992
1993 // Rewrite constant pool references in the element_value portion of an
1994 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1995 // the 2nd-edition of the VM spec:
1996 //
1997 // struct element_value {
1998 // u1 tag;
1999 // union {
2000 // u2 const_value_index;
2001 // {
2002 // u2 type_name_index;
2003 // u2 const_name_index;
2004 // } enum_const_value;
2005 // u2 class_info_index;
2006 // annotation annotation_value;
2007 // struct {
2008 // u2 num_values;
2009 // element_value values[num_values];
2010 // } array_value;
2011 // } value;
2012 // }
2013 //
2014 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2015 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2016
2017 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2018 // not enough room for a tag let alone the rest of an element_value
2019 log_debug(redefine, class, annotation)("length() is too small for a tag");
2020 return false;
2021 }
2022
2023 u1 tag = annotations_typeArray->at(byte_i_ref);
2024 byte_i_ref++;
2025 log_debug(redefine, class, annotation)("tag='%c'", tag);
2026
2027 switch (tag) {
2028 // These BaseType tag values are from Table 4.2 in VM spec:
2029 case 'B': // byte
2030 case 'C': // char
2031 case 'D': // double
2032 case 'F': // float
2033 case 'I': // int
2034 case 'J': // long
2035 case 'S': // short
2036 case 'Z': // boolean
2037
2038 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2039 // the VM spec:
2040 case 's':
2041 {
2042 // For the above tag values (including the BaseType values),
2043 // value.const_value_index is right union field.
2044
2045 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2046 // not enough room for a const_value_index
2047 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2048 return false;
2049 }
2050
2051 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2052 annotations_typeArray, byte_i_ref,
2053 "const_value_index", THREAD);
2054
2055 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2056 } break;
2057
2058 case 'e':
2059 {
2060 // for the above tag value, value.enum_const_value is right union field
2061
2062 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2063 // not enough room for a enum_const_value
2064 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2065 return false;
2066 }
2067
2068 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2069 annotations_typeArray, byte_i_ref,
2070 "type_name_index", THREAD);
2071
2072 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2073 annotations_typeArray, byte_i_ref,
2074 "const_name_index", THREAD);
2075
2076 log_debug(redefine, class, annotation)
2077 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2078 } break;
2079
2080 case 'c':
2081 {
2082 // for the above tag value, value.class_info_index is right union field
2083
2084 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2085 // not enough room for a class_info_index
2086 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2087 return false;
2088 }
2089
2090 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2091 annotations_typeArray, byte_i_ref,
2092 "class_info_index", THREAD);
2093
2094 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2095 } break;
2096
2097 case '@':
2098 // For the above tag value, value.attr_value is the right union
2099 // field. This is a nested annotation.
2100 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2101 byte_i_ref, THREAD)) {
2102 // propagate failure back to caller
2103 return false;
2104 }
2105 break;
2106
2107 case '[':
2108 {
2109 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2110 // not enough room for a num_values field
2111 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2112 return false;
2113 }
2114
2115 // For the above tag value, value.array_value is the right union
2116 // field. This is an array of nested element_value.
2117 u2 num_values = Bytes::get_Java_u2((address)
2118 annotations_typeArray->adr_at(byte_i_ref));
2119 byte_i_ref += 2;
2120 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2121
2122 int calc_num_values = 0;
2123 for (; calc_num_values < num_values; calc_num_values++) {
2124 if (!rewrite_cp_refs_in_element_value(
2125 annotations_typeArray, byte_i_ref, THREAD)) {
2126 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2127 // propagate failure back to caller
2128 return false;
2129 }
2130 }
2131 assert(num_values == calc_num_values, "sanity check");
2132 } break;
2133
2134 default:
2135 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2136 return false;
2137 } // end decode tag field
2138
2139 return true;
2140 } // end rewrite_cp_refs_in_element_value()
2141
2142
2143 // Rewrite constant pool references in a fields_annotations field.
2144 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2145 InstanceKlass* scratch_class, TRAPS) {
2146
2147 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2148
2149 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2150 // no fields_annotations so nothing to do
2151 return true;
2152 }
2153
2154 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2155
2156 for (int i = 0; i < fields_annotations->length(); i++) {
2157 AnnotationArray* field_annotations = fields_annotations->at(i);
2158 if (field_annotations == NULL || field_annotations->length() == 0) {
2159 // this field does not have any annotations so skip it
2160 continue;
2161 }
2162
2163 int byte_i = 0; // byte index into field_annotations
2164 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2165 THREAD)) {
2166 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2167 // propagate failure back to caller
2168 return false;
2169 }
2170 }
2171
2172 return true;
2173 } // end rewrite_cp_refs_in_fields_annotations()
2174
2175
2176 // Rewrite constant pool references in a methods_annotations field.
2177 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2178 InstanceKlass* scratch_class, TRAPS) {
2179
2180 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2181 Method* m = scratch_class->methods()->at(i);
2182 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2183
2184 if (method_annotations == NULL || method_annotations->length() == 0) {
2185 // this method does not have any annotations so skip it
2186 continue;
2187 }
2188
2189 int byte_i = 0; // byte index into method_annotations
2190 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2191 THREAD)) {
2192 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2193 // propagate failure back to caller
2194 return false;
2195 }
2196 }
2197
2198 return true;
2199 } // end rewrite_cp_refs_in_methods_annotations()
2200
2201
2202 // Rewrite constant pool references in a methods_parameter_annotations
2203 // field. This "structure" is adapted from the
2204 // RuntimeVisibleParameterAnnotations_attribute described in section
2205 // 4.8.17 of the 2nd-edition of the VM spec:
2206 //
2207 // methods_parameter_annotations_typeArray {
2208 // u1 num_parameters;
2209 // {
2210 // u2 num_annotations;
2211 // annotation annotations[num_annotations];
2212 // } parameter_annotations[num_parameters];
2213 // }
2214 //
2215 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2216 InstanceKlass* scratch_class, TRAPS) {
2217
2218 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2219 Method* m = scratch_class->methods()->at(i);
2220 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2221 if (method_parameter_annotations == NULL
2222 || method_parameter_annotations->length() == 0) {
2223 // this method does not have any parameter annotations so skip it
2224 continue;
2225 }
2226
2227 if (method_parameter_annotations->length() < 1) {
2228 // not enough room for a num_parameters field
2229 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2230 return false;
2231 }
2232
2233 int byte_i = 0; // byte index into method_parameter_annotations
2234
2235 u1 num_parameters = method_parameter_annotations->at(byte_i);
2236 byte_i++;
2237
2238 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2239
2240 int calc_num_parameters = 0;
2241 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2242 if (!rewrite_cp_refs_in_annotations_typeArray(
2243 method_parameter_annotations, byte_i, THREAD)) {
2244 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2245 // propagate failure back to caller
2246 return false;
2247 }
2248 }
2249 assert(num_parameters == calc_num_parameters, "sanity check");
2250 }
2251
2252 return true;
2253 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2254
2255
2256 // Rewrite constant pool references in a methods_default_annotations
2257 // field. This "structure" is adapted from the AnnotationDefault_attribute
2258 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2259 //
2260 // methods_default_annotations_typeArray {
2261 // element_value default_value;
2262 // }
2263 //
2264 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2265 InstanceKlass* scratch_class, TRAPS) {
2266
2267 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2268 Method* m = scratch_class->methods()->at(i);
2269 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2270 if (method_default_annotations == NULL
2271 || method_default_annotations->length() == 0) {
2272 // this method does not have any default annotations so skip it
2273 continue;
2274 }
2275
2276 int byte_i = 0; // byte index into method_default_annotations
2277
2278 if (!rewrite_cp_refs_in_element_value(
2279 method_default_annotations, byte_i, THREAD)) {
2280 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2281 // propagate failure back to caller
2282 return false;
2283 }
2284 }
2285
2286 return true;
2287 } // end rewrite_cp_refs_in_methods_default_annotations()
2288
2289
2290 // Rewrite constant pool references in a class_type_annotations field.
2291 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2292 InstanceKlass* scratch_class, TRAPS) {
2293
2294 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2295 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2296 // no class_type_annotations so nothing to do
2297 return true;
2298 }
2299
2300 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2301
2302 int byte_i = 0; // byte index into class_type_annotations
2303 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2304 byte_i, "ClassFile", THREAD);
2305 } // end rewrite_cp_refs_in_class_type_annotations()
2306
2307
2308 // Rewrite constant pool references in a fields_type_annotations field.
2309 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2310 InstanceKlass* scratch_class, TRAPS) {
2311
2312 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2313 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2314 // no fields_type_annotations so nothing to do
2315 return true;
2316 }
2317
2318 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2319
2320 for (int i = 0; i < fields_type_annotations->length(); i++) {
2321 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2322 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2323 // this field does not have any annotations so skip it
2324 continue;
2325 }
2326
2327 int byte_i = 0; // byte index into field_type_annotations
2328 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2329 byte_i, "field_info", THREAD)) {
2330 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2331 // propagate failure back to caller
2332 return false;
2333 }
2334 }
2335
2336 return true;
2337 } // end rewrite_cp_refs_in_fields_type_annotations()
2338
2339
2340 // Rewrite constant pool references in a methods_type_annotations field.
2341 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2342 InstanceKlass* scratch_class, TRAPS) {
2343
2344 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2345 Method* m = scratch_class->methods()->at(i);
2346 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2347
2348 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2349 // this method does not have any annotations so skip it
2350 continue;
2351 }
2352
2353 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2354
2355 int byte_i = 0; // byte index into method_type_annotations
2356 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2357 byte_i, "method_info", THREAD)) {
2358 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2359 // propagate failure back to caller
2360 return false;
2361 }
2362 }
2363
2364 return true;
2365 } // end rewrite_cp_refs_in_methods_type_annotations()
2366
2367
2368 // Rewrite constant pool references in a type_annotations
2369 // field. This "structure" is adapted from the
2370 // RuntimeVisibleTypeAnnotations_attribute described in
2371 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2372 //
2373 // type_annotations_typeArray {
2374 // u2 num_annotations;
2375 // type_annotation annotations[num_annotations];
2376 // }
2377 //
2378 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2379 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2380 const char * location_mesg, TRAPS) {
2381
2382 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2383 // not enough room for num_annotations field
2384 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2385 return false;
2386 }
2387
2388 u2 num_annotations = Bytes::get_Java_u2((address)
2389 type_annotations_typeArray->adr_at(byte_i_ref));
2390 byte_i_ref += 2;
2391
2392 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2393
2394 int calc_num_annotations = 0;
2395 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2396 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2397 byte_i_ref, location_mesg, THREAD)) {
2398 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2399 // propagate failure back to caller
2400 return false;
2401 }
2402 }
2403 assert(num_annotations == calc_num_annotations, "sanity check");
2404
2405 if (byte_i_ref != type_annotations_typeArray->length()) {
2406 log_debug(redefine, class, annotation)
2407 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2408 byte_i_ref, type_annotations_typeArray->length());
2409 return false;
2410 }
2411
2412 return true;
2413 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2414
2415
2416 // Rewrite constant pool references in a type_annotation
2417 // field. This "structure" is adapted from the
2418 // RuntimeVisibleTypeAnnotations_attribute described in
2419 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2420 //
2421 // type_annotation {
2422 // u1 target_type;
2423 // union {
2424 // type_parameter_target;
2425 // supertype_target;
2426 // type_parameter_bound_target;
2427 // empty_target;
2428 // method_formal_parameter_target;
2429 // throws_target;
2430 // localvar_target;
2431 // catch_target;
2432 // offset_target;
2433 // type_argument_target;
2434 // } target_info;
2435 // type_path target_path;
2436 // annotation anno;
2437 // }
2438 //
2439 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2440 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2441 const char * location_mesg, TRAPS) {
2442
2443 if (!skip_type_annotation_target(type_annotations_typeArray,
2444 byte_i_ref, location_mesg, THREAD)) {
2445 return false;
2446 }
2447
2448 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2449 byte_i_ref, THREAD)) {
2450 return false;
2451 }
2452
2453 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2454 byte_i_ref, THREAD)) {
2455 return false;
2456 }
2457
2458 return true;
2459 } // end rewrite_cp_refs_in_type_annotation_struct()
2460
2461
2462 // Read, verify and skip over the target_type and target_info part
2463 // so that rewriting can continue in the later parts of the struct.
2464 //
2465 // u1 target_type;
2466 // union {
2467 // type_parameter_target;
2468 // supertype_target;
2469 // type_parameter_bound_target;
2470 // empty_target;
2471 // method_formal_parameter_target;
2472 // throws_target;
2473 // localvar_target;
2474 // catch_target;
2475 // offset_target;
2476 // type_argument_target;
2477 // } target_info;
2478 //
2479 bool VM_RedefineClasses::skip_type_annotation_target(
2480 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2481 const char * location_mesg, TRAPS) {
2482
2483 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2484 // not enough room for a target_type let alone the rest of a type_annotation
2485 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2486 return false;
2487 }
2488
2489 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2490 byte_i_ref += 1;
2491 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2492 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2493
2494 // Skip over target_info
2495 switch (target_type) {
2496 case 0x00:
2497 // kind: type parameter declaration of generic class or interface
2498 // location: ClassFile
2499 case 0x01:
2500 // kind: type parameter declaration of generic method or constructor
2501 // location: method_info
2502
2503 {
2504 // struct:
2505 // type_parameter_target {
2506 // u1 type_parameter_index;
2507 // }
2508 //
2509 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2510 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2511 return false;
2512 }
2513
2514 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2515 byte_i_ref += 1;
2516
2517 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2518 } break;
2519
2520 case 0x10:
2521 // kind: type in extends clause of class or interface declaration
2522 // (including the direct superclass of an anonymous class declaration),
2523 // or in implements clause of interface declaration
2524 // location: ClassFile
2525
2526 {
2527 // struct:
2528 // supertype_target {
2529 // u2 supertype_index;
2530 // }
2531 //
2532 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2533 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2534 return false;
2535 }
2536
2537 u2 supertype_index = Bytes::get_Java_u2((address)
2538 type_annotations_typeArray->adr_at(byte_i_ref));
2539 byte_i_ref += 2;
2540
2541 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2542 } break;
2543
2544 case 0x11:
2545 // kind: type in bound of type parameter declaration of generic class or interface
2546 // location: ClassFile
2547 case 0x12:
2548 // kind: type in bound of type parameter declaration of generic method or constructor
2549 // location: method_info
2550
2551 {
2552 // struct:
2553 // type_parameter_bound_target {
2554 // u1 type_parameter_index;
2555 // u1 bound_index;
2556 // }
2557 //
2558 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2559 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2560 return false;
2561 }
2562
2563 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2564 byte_i_ref += 1;
2565 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2566 byte_i_ref += 1;
2567
2568 log_debug(redefine, class, annotation)
2569 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2570 } break;
2571
2572 case 0x13:
2573 // kind: type in field declaration
2574 // location: field_info
2575 case 0x14:
2576 // kind: return type of method, or type of newly constructed object
2577 // location: method_info
2578 case 0x15:
2579 // kind: receiver type of method or constructor
2580 // location: method_info
2581
2582 {
2583 // struct:
2584 // empty_target {
2585 // }
2586 //
2587 log_debug(redefine, class, annotation)("empty_target");
2588 } break;
2589
2590 case 0x16:
2591 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2592 // location: method_info
2593
2594 {
2595 // struct:
2596 // formal_parameter_target {
2597 // u1 formal_parameter_index;
2598 // }
2599 //
2600 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2601 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2602 return false;
2603 }
2604
2605 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2606 byte_i_ref += 1;
2607
2608 log_debug(redefine, class, annotation)
2609 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2610 } break;
2611
2612 case 0x17:
2613 // kind: type in throws clause of method or constructor
2614 // location: method_info
2615
2616 {
2617 // struct:
2618 // throws_target {
2619 // u2 throws_type_index
2620 // }
2621 //
2622 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2623 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2624 return false;
2625 }
2626
2627 u2 throws_type_index = Bytes::get_Java_u2((address)
2628 type_annotations_typeArray->adr_at(byte_i_ref));
2629 byte_i_ref += 2;
2630
2631 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2632 } break;
2633
2634 case 0x40:
2635 // kind: type in local variable declaration
2636 // location: Code
2637 case 0x41:
2638 // kind: type in resource variable declaration
2639 // location: Code
2640
2641 {
2642 // struct:
2643 // localvar_target {
2644 // u2 table_length;
2645 // struct {
2646 // u2 start_pc;
2647 // u2 length;
2648 // u2 index;
2649 // } table[table_length];
2650 // }
2651 //
2652 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2653 // not enough room for a table_length let alone the rest of a localvar_target
2654 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2655 return false;
2656 }
2657
2658 u2 table_length = Bytes::get_Java_u2((address)
2659 type_annotations_typeArray->adr_at(byte_i_ref));
2660 byte_i_ref += 2;
2661
2662 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2663
2664 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2665 int table_size = table_length * table_struct_size;
2666
2667 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2668 // not enough room for a table
2669 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2670 return false;
2671 }
2672
2673 // Skip over table
2674 byte_i_ref += table_size;
2675 } break;
2676
2677 case 0x42:
2678 // kind: type in exception parameter declaration
2679 // location: Code
2680
2681 {
2682 // struct:
2683 // catch_target {
2684 // u2 exception_table_index;
2685 // }
2686 //
2687 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2688 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2689 return false;
2690 }
2691
2692 u2 exception_table_index = Bytes::get_Java_u2((address)
2693 type_annotations_typeArray->adr_at(byte_i_ref));
2694 byte_i_ref += 2;
2695
2696 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2697 } break;
2698
2699 case 0x43:
2700 // kind: type in instanceof expression
2701 // location: Code
2702 case 0x44:
2703 // kind: type in new expression
2704 // location: Code
2705 case 0x45:
2706 // kind: type in method reference expression using ::new
2707 // location: Code
2708 case 0x46:
2709 // kind: type in method reference expression using ::Identifier
2710 // location: Code
2711
2712 {
2713 // struct:
2714 // offset_target {
2715 // u2 offset;
2716 // }
2717 //
2718 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2719 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2720 return false;
2721 }
2722
2723 u2 offset = Bytes::get_Java_u2((address)
2724 type_annotations_typeArray->adr_at(byte_i_ref));
2725 byte_i_ref += 2;
2726
2727 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2728 } break;
2729
2730 case 0x47:
2731 // kind: type in cast expression
2732 // location: Code
2733 case 0x48:
2734 // kind: type argument for generic constructor in new expression or
2735 // explicit constructor invocation statement
2736 // location: Code
2737 case 0x49:
2738 // kind: type argument for generic method in method invocation expression
2739 // location: Code
2740 case 0x4A:
2741 // kind: type argument for generic constructor in method reference expression using ::new
2742 // location: Code
2743 case 0x4B:
2744 // kind: type argument for generic method in method reference expression using ::Identifier
2745 // location: Code
2746
2747 {
2748 // struct:
2749 // type_argument_target {
2750 // u2 offset;
2751 // u1 type_argument_index;
2752 // }
2753 //
2754 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2755 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2756 return false;
2757 }
2758
2759 u2 offset = Bytes::get_Java_u2((address)
2760 type_annotations_typeArray->adr_at(byte_i_ref));
2761 byte_i_ref += 2;
2762 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2763 byte_i_ref += 1;
2764
2765 log_debug(redefine, class, annotation)
2766 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2767 } break;
2768
2769 default:
2770 log_debug(redefine, class, annotation)("unknown target_type");
2771 #ifdef ASSERT
2772 ShouldNotReachHere();
2773 #endif
2774 return false;
2775 }
2776
2777 return true;
2778 } // end skip_type_annotation_target()
2779
2780
2781 // Read, verify and skip over the type_path part so that rewriting
2782 // can continue in the later parts of the struct.
2783 //
2784 // type_path {
2785 // u1 path_length;
2786 // {
2787 // u1 type_path_kind;
2788 // u1 type_argument_index;
2789 // } path[path_length];
2790 // }
2791 //
2792 bool VM_RedefineClasses::skip_type_annotation_type_path(
2793 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2794
2795 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2796 // not enough room for a path_length let alone the rest of the type_path
2797 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2798 return false;
2799 }
2800
2801 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2802 byte_i_ref += 1;
2803
2804 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2805
2806 int calc_path_length = 0;
2807 for (; calc_path_length < path_length; calc_path_length++) {
2808 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2809 // not enough room for a path
2810 log_debug(redefine, class, annotation)
2811 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2812 return false;
2813 }
2814
2815 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2816 byte_i_ref += 1;
2817 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2818 byte_i_ref += 1;
2819
2820 log_debug(redefine, class, annotation)
2821 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2822 calc_path_length, type_path_kind, type_argument_index);
2823
2824 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2825 // not enough room for a path
2826 log_debug(redefine, class, annotation)("inconsistent type_path values");
2827 return false;
2828 }
2829 }
2830 assert(path_length == calc_path_length, "sanity check");
2831
2832 return true;
2833 } // end skip_type_annotation_type_path()
2834
2835
2836 // Rewrite constant pool references in the method's stackmap table.
2837 // These "structures" are adapted from the StackMapTable_attribute that
2838 // is described in section 4.8.4 of the 6.0 version of the VM spec
2839 // (dated 2005.10.26):
2840 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2841 //
2842 // stack_map {
2843 // u2 number_of_entries;
2844 // stack_map_frame entries[number_of_entries];
2845 // }
2846 //
2847 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2848 const methodHandle& method, TRAPS) {
2849
2850 if (!method->has_stackmap_table()) {
2851 return;
2852 }
2853
2854 AnnotationArray* stackmap_data = method->stackmap_data();
2855 address stackmap_p = (address)stackmap_data->adr_at(0);
2856 address stackmap_end = stackmap_p + stackmap_data->length();
2857
2858 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2859 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2860 stackmap_p += 2;
2861
2862 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2863
2864 // walk through each stack_map_frame
2865 u2 calc_number_of_entries = 0;
2866 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2867 // The stack_map_frame structure is a u1 frame_type followed by
2868 // 0 or more bytes of data:
2869 //
2870 // union stack_map_frame {
2871 // same_frame;
2872 // same_locals_1_stack_item_frame;
2873 // same_locals_1_stack_item_frame_extended;
2874 // chop_frame;
2875 // same_frame_extended;
2876 // append_frame;
2877 // full_frame;
2878 // }
2879
2880 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2881 u1 frame_type = *stackmap_p;
2882 stackmap_p++;
2883
2884 // same_frame {
2885 // u1 frame_type = SAME; /* 0-63 */
2886 // }
2887 if (frame_type <= 63) {
2888 // nothing more to do for same_frame
2889 }
2890
2891 // same_locals_1_stack_item_frame {
2892 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2893 // verification_type_info stack[1];
2894 // }
2895 else if (frame_type >= 64 && frame_type <= 127) {
2896 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2897 calc_number_of_entries, frame_type, THREAD);
2898 }
2899
2900 // reserved for future use
2901 else if (frame_type >= 128 && frame_type <= 246) {
2902 // nothing more to do for reserved frame_types
2903 }
2904
2905 // same_locals_1_stack_item_frame_extended {
2906 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2907 // u2 offset_delta;
2908 // verification_type_info stack[1];
2909 // }
2910 else if (frame_type == 247) {
2911 stackmap_p += 2;
2912 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2913 calc_number_of_entries, frame_type, THREAD);
2914 }
2915
2916 // chop_frame {
2917 // u1 frame_type = CHOP; /* 248-250 */
2918 // u2 offset_delta;
2919 // }
2920 else if (frame_type >= 248 && frame_type <= 250) {
2921 stackmap_p += 2;
2922 }
2923
2924 // same_frame_extended {
2925 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2926 // u2 offset_delta;
2927 // }
2928 else if (frame_type == 251) {
2929 stackmap_p += 2;
2930 }
2931
2932 // append_frame {
2933 // u1 frame_type = APPEND; /* 252-254 */
2934 // u2 offset_delta;
2935 // verification_type_info locals[frame_type - 251];
2936 // }
2937 else if (frame_type >= 252 && frame_type <= 254) {
2938 assert(stackmap_p + 2 <= stackmap_end,
2939 "no room for offset_delta");
2940 stackmap_p += 2;
2941 u1 len = frame_type - 251;
2942 for (u1 i = 0; i < len; i++) {
2943 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2944 calc_number_of_entries, frame_type, THREAD);
2945 }
2946 }
2947
2948 // full_frame {
2949 // u1 frame_type = FULL_FRAME; /* 255 */
2950 // u2 offset_delta;
2951 // u2 number_of_locals;
2952 // verification_type_info locals[number_of_locals];
2953 // u2 number_of_stack_items;
2954 // verification_type_info stack[number_of_stack_items];
2955 // }
2956 else if (frame_type == 255) {
2957 assert(stackmap_p + 2 + 2 <= stackmap_end,
2958 "no room for smallest full_frame");
2959 stackmap_p += 2;
2960
2961 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2962 stackmap_p += 2;
2963
2964 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2965 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2966 calc_number_of_entries, frame_type, THREAD);
2967 }
2968
2969 // Use the largest size for the number_of_stack_items, but only get
2970 // the right number of bytes.
2971 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2972 stackmap_p += 2;
2973
2974 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2975 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2976 calc_number_of_entries, frame_type, THREAD);
2977 }
2978 }
2979 } // end while there is a stack_map_frame
2980 assert(number_of_entries == calc_number_of_entries, "sanity check");
2981 } // end rewrite_cp_refs_in_stack_map_table()
2982
2983
2984 // Rewrite constant pool references in the verification type info
2985 // portion of the method's stackmap table. These "structures" are
2986 // adapted from the StackMapTable_attribute that is described in
2987 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2988 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2989 //
2990 // The verification_type_info structure is a u1 tag followed by 0 or
2991 // more bytes of data:
2992 //
2993 // union verification_type_info {
2994 // Top_variable_info;
2995 // Integer_variable_info;
2996 // Float_variable_info;
2997 // Long_variable_info;
2998 // Double_variable_info;
2999 // Null_variable_info;
3000 // UninitializedThis_variable_info;
3001 // Object_variable_info;
3002 // Uninitialized_variable_info;
3003 // }
3004 //
3005 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3006 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3007 u1 frame_type, TRAPS) {
3008
3009 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3010 u1 tag = *stackmap_p_ref;
3011 stackmap_p_ref++;
3012
3013 switch (tag) {
3014 // Top_variable_info {
3015 // u1 tag = ITEM_Top; /* 0 */
3016 // }
3017 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3018 case 0: // fall through
3019
3020 // Integer_variable_info {
3021 // u1 tag = ITEM_Integer; /* 1 */
3022 // }
3023 case ITEM_Integer: // fall through
3024
3025 // Float_variable_info {
3026 // u1 tag = ITEM_Float; /* 2 */
3027 // }
3028 case ITEM_Float: // fall through
3029
3030 // Double_variable_info {
3031 // u1 tag = ITEM_Double; /* 3 */
3032 // }
3033 case ITEM_Double: // fall through
3034
3035 // Long_variable_info {
3036 // u1 tag = ITEM_Long; /* 4 */
3037 // }
3038 case ITEM_Long: // fall through
3039
3040 // Null_variable_info {
3041 // u1 tag = ITEM_Null; /* 5 */
3042 // }
3043 case ITEM_Null: // fall through
3044
3045 // UninitializedThis_variable_info {
3046 // u1 tag = ITEM_UninitializedThis; /* 6 */
3047 // }
3048 case ITEM_UninitializedThis:
3049 // nothing more to do for the above tag types
3050 break;
3051
3052 // Object_variable_info {
3053 // u1 tag = ITEM_Object; /* 7 */
3054 // u2 cpool_index;
3055 // }
3056 case ITEM_Object:
3057 {
3058 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3059 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3060 u2 new_cp_index = find_new_index(cpool_index);
3061 if (new_cp_index != 0) {
3062 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3063 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3064 cpool_index = new_cp_index;
3065 }
3066 stackmap_p_ref += 2;
3067
3068 log_debug(redefine, class, stackmap)
3069 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3070 } break;
3071
3072 // Uninitialized_variable_info {
3073 // u1 tag = ITEM_Uninitialized; /* 8 */
3074 // u2 offset;
3075 // }
3076 case ITEM_Uninitialized:
3077 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3078 stackmap_p_ref += 2;
3079 break;
3080
3081 default:
3082 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3083 ShouldNotReachHere();
3084 break;
3085 } // end switch (tag)
3086 } // end rewrite_cp_refs_in_verification_type_info()
3087
3088
3089 // Change the constant pool associated with klass scratch_class to
3090 // scratch_cp. If shrink is true, then scratch_cp_length elements
3091 // are copied from scratch_cp to a smaller constant pool and the
3092 // smaller constant pool is associated with scratch_class.
3093 void VM_RedefineClasses::set_new_constant_pool(
3094 ClassLoaderData* loader_data,
3095 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3096 int scratch_cp_length, TRAPS) {
3097 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3098
3099 // scratch_cp is a merged constant pool and has enough space for a
3100 // worst case merge situation. We want to associate the minimum
3101 // sized constant pool with the klass to save space.
3102 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3103 constantPoolHandle smaller_cp(THREAD, cp);
3104
3105 // preserve version() value in the smaller copy
3106 int version = scratch_cp->version();
3107 assert(version != 0, "sanity check");
3108 smaller_cp->set_version(version);
3109
3110 // attach klass to new constant pool
3111 // reference to the cp holder is needed for copy_operands()
3112 smaller_cp->set_pool_holder(scratch_class);
3113
3114 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3115 if (HAS_PENDING_EXCEPTION) {
3116 // Exception is handled in the caller
3117 loader_data->add_to_deallocate_list(smaller_cp());
3118 return;
3119 }
3120 scratch_cp = smaller_cp;
3121
3122 // attach new constant pool to klass
3123 scratch_class->set_constants(scratch_cp());
3124 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3125
3126 int i; // for portability
3127
3128 // update each field in klass to use new constant pool indices as needed
3129 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3130 jshort cur_index = fs.name_index();
3131 jshort new_index = find_new_index(cur_index);
3132 if (new_index != 0) {
3133 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3134 fs.set_name_index(new_index);
3135 }
3136 cur_index = fs.signature_index();
3137 new_index = find_new_index(cur_index);
3138 if (new_index != 0) {
3139 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3140 fs.set_signature_index(new_index);
3141 }
3142 cur_index = fs.initval_index();
3143 new_index = find_new_index(cur_index);
3144 if (new_index != 0) {
3145 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3146 fs.set_initval_index(new_index);
3147 }
3148 cur_index = fs.generic_signature_index();
3149 new_index = find_new_index(cur_index);
3150 if (new_index != 0) {
3151 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3152 fs.set_generic_signature_index(new_index);
3153 }
3154 } // end for each field
3155
3156 // Update constant pool indices in the inner classes info to use
3157 // new constant indices as needed. The inner classes info is a
3158 // quadruple:
3159 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3160 InnerClassesIterator iter(scratch_class);
3161 for (; !iter.done(); iter.next()) {
3162 int cur_index = iter.inner_class_info_index();
3163 if (cur_index == 0) {
3164 continue; // JVM spec. allows null inner class refs so skip it
3165 }
3166 int new_index = find_new_index(cur_index);
3167 if (new_index != 0) {
3168 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3169 iter.set_inner_class_info_index(new_index);
3170 }
3171 cur_index = iter.outer_class_info_index();
3172 new_index = find_new_index(cur_index);
3173 if (new_index != 0) {
3174 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3175 iter.set_outer_class_info_index(new_index);
3176 }
3177 cur_index = iter.inner_name_index();
3178 new_index = find_new_index(cur_index);
3179 if (new_index != 0) {
3180 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3181 iter.set_inner_name_index(new_index);
3182 }
3183 } // end for each inner class
3184
3185 // Attach each method in klass to the new constant pool and update
3186 // to use new constant pool indices as needed:
3187 Array<Method*>* methods = scratch_class->methods();
3188 for (i = methods->length() - 1; i >= 0; i--) {
3189 methodHandle method(THREAD, methods->at(i));
3190 method->set_constants(scratch_cp());
3191
3192 int new_index = find_new_index(method->name_index());
3193 if (new_index != 0) {
3194 log_trace(redefine, class, constantpool)
3195 ("method-name_index change: %d to %d", method->name_index(), new_index);
3196 method->set_name_index(new_index);
3197 }
3198 new_index = find_new_index(method->signature_index());
3199 if (new_index != 0) {
3200 log_trace(redefine, class, constantpool)
3201 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3202 method->set_signature_index(new_index);
3203 }
3204 new_index = find_new_index(method->generic_signature_index());
3205 if (new_index != 0) {
3206 log_trace(redefine, class, constantpool)
3207 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3208 method->set_generic_signature_index(new_index);
3209 }
3210
3211 // Update constant pool indices in the method's checked exception
3212 // table to use new constant indices as needed.
3213 int cext_length = method->checked_exceptions_length();
3214 if (cext_length > 0) {
3215 CheckedExceptionElement * cext_table =
3216 method->checked_exceptions_start();
3217 for (int j = 0; j < cext_length; j++) {
3218 int cur_index = cext_table[j].class_cp_index;
3219 int new_index = find_new_index(cur_index);
3220 if (new_index != 0) {
3221 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3222 cext_table[j].class_cp_index = (u2)new_index;
3223 }
3224 } // end for each checked exception table entry
3225 } // end if there are checked exception table entries
3226
3227 // Update each catch type index in the method's exception table
3228 // to use new constant pool indices as needed. The exception table
3229 // holds quadruple entries of the form:
3230 // (beg_bci, end_bci, handler_bci, klass_index)
3231
3232 ExceptionTable ex_table(method());
3233 int ext_length = ex_table.length();
3234
3235 for (int j = 0; j < ext_length; j ++) {
3236 int cur_index = ex_table.catch_type_index(j);
3237 int new_index = find_new_index(cur_index);
3238 if (new_index != 0) {
3239 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3240 ex_table.set_catch_type_index(j, new_index);
3241 }
3242 } // end for each exception table entry
3243
3244 // Update constant pool indices in the method's local variable
3245 // table to use new constant indices as needed. The local variable
3246 // table hold sextuple entries of the form:
3247 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3248 int lvt_length = method->localvariable_table_length();
3249 if (lvt_length > 0) {
3250 LocalVariableTableElement * lv_table =
3251 method->localvariable_table_start();
3252 for (int j = 0; j < lvt_length; j++) {
3253 int cur_index = lv_table[j].name_cp_index;
3254 int new_index = find_new_index(cur_index);
3255 if (new_index != 0) {
3256 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3257 lv_table[j].name_cp_index = (u2)new_index;
3258 }
3259 cur_index = lv_table[j].descriptor_cp_index;
3260 new_index = find_new_index(cur_index);
3261 if (new_index != 0) {
3262 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3263 lv_table[j].descriptor_cp_index = (u2)new_index;
3264 }
3265 cur_index = lv_table[j].signature_cp_index;
3266 new_index = find_new_index(cur_index);
3267 if (new_index != 0) {
3268 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3269 lv_table[j].signature_cp_index = (u2)new_index;
3270 }
3271 } // end for each local variable table entry
3272 } // end if there are local variable table entries
3273
3274 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3275 } // end for each method
3276 } // end set_new_constant_pool()
3277
3278
3279 // Unevolving classes may point to methods of the_class directly
3280 // from their constant pool caches, itables, and/or vtables. We
3281 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3282 // to fix up these pointers.
3283
3284 // Adjust cpools and vtables closure
3285 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3286
3287 // This is a very busy routine. We don't want too much tracing
3288 // printed out.
3289 bool trace_name_printed = false;
3290 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3291
3292 // If the class being redefined is java.lang.Object, we need to fix all
3293 // array class vtables also
3294 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3295 k->vtable().adjust_method_entries(the_class, &trace_name_printed);
3296
3297 } else if (k->is_instance_klass()) {
3298 HandleMark hm(_thread);
3299 InstanceKlass *ik = InstanceKlass::cast(k);
3300
3301 // HotSpot specific optimization! HotSpot does not currently
3302 // support delegation from the bootstrap class loader to a
3303 // user-defined class loader. This means that if the bootstrap
3304 // class loader is the initiating class loader, then it will also
3305 // be the defining class loader. This also means that classes
3306 // loaded by the bootstrap class loader cannot refer to classes
3307 // loaded by a user-defined class loader. Note: a user-defined
3308 // class loader can delegate to the bootstrap class loader.
3309 //
3310 // If the current class being redefined has a user-defined class
3311 // loader as its defining class loader, then we can skip all
3312 // classes loaded by the bootstrap class loader.
3313 bool is_user_defined = (_the_class->class_loader() != NULL);
3314 if (is_user_defined && ik->class_loader() == NULL) {
3315 return;
3316 }
3317
3318 // Fix the vtable embedded in the_class and subclasses of the_class,
3319 // if one exists. We discard scratch_class and we don't keep an
3320 // InstanceKlass around to hold obsolete methods so we don't have
3321 // any other InstanceKlass embedded vtables to update. The vtable
3322 // holds the Method*s for virtual (but not final) methods.
3323 // Default methods, or concrete methods in interfaces are stored
3324 // in the vtable, so if an interface changes we need to check
3325 // adjust_method_entries() for every InstanceKlass, which will also
3326 // adjust the default method vtable indices.
3327 // We also need to adjust any default method entries that are
3328 // not yet in the vtable, because the vtable setup is in progress.
3329 // This must be done after we adjust the default_methods and
3330 // default_vtable_indices for methods already in the vtable.
3331 // If redefining Unsafe, walk all the vtables looking for entries.
3332 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3333 || _the_class == SystemDictionary::internal_Unsafe_klass()
3334 || ik->is_subtype_of(_the_class))) {
3335 // ik->vtable() creates a wrapper object; rm cleans it up
3336 ResourceMark rm(_thread);
3337
3338 ik->vtable().adjust_method_entries(the_class, &trace_name_printed);
3339 ik->adjust_default_methods(the_class, &trace_name_printed);
3340 }
3341
3342 // If the current class has an itable and we are either redefining an
3343 // interface or if the current class is a subclass of the_class, then
3344 // we potentially have to fix the itable. If we are redefining an
3345 // interface, then we have to call adjust_method_entries() for
3346 // every InstanceKlass that has an itable since there isn't a
3347 // subclass relationship between an interface and an InstanceKlass.
3348 // If redefining Unsafe, walk all the itables looking for entries.
3349 if (ik->itable_length() > 0 && (_the_class->is_interface()
3350 || _the_class == SystemDictionary::internal_Unsafe_klass()
3351 || ik->is_subclass_of(_the_class))) {
3352 ResourceMark rm(_thread);
3353 ik->itable().adjust_method_entries(the_class, &trace_name_printed);
3354 }
3355
3356 // The constant pools in other classes (other_cp) can refer to
3357 // methods in the_class. We have to update method information in
3358 // other_cp's cache. If other_cp has a previous version, then we
3359 // have to repeat the process for each previous version. The
3360 // constant pool cache holds the Method*s for non-virtual
3361 // methods and for virtual, final methods.
3362 //
3363 // Special case: if the current class is the_class, then new_cp
3364 // has already been attached to the_class and old_cp has already
3365 // been added as a previous version. The new_cp doesn't have any
3366 // cached references to old methods so it doesn't need to be
3367 // updated. We can simply start with the previous version(s) in
3368 // that case.
3369 constantPoolHandle other_cp;
3370 ConstantPoolCache* cp_cache;
3371
3372 if (ik != _the_class) {
3373 // this klass' constant pool cache may need adjustment
3374 other_cp = constantPoolHandle(ik->constants());
3375 cp_cache = other_cp->cache();
3376 if (cp_cache != NULL) {
3377 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3378 }
3379 }
3380
3381 // the previous versions' constant pool caches may need adjustment
3382 for (InstanceKlass* pv_node = ik->previous_versions();
3383 pv_node != NULL;
3384 pv_node = pv_node->previous_versions()) {
3385 cp_cache = pv_node->constants()->cache();
3386 if (cp_cache != NULL) {
3387 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3388 }
3389 }
3390 }
3391 }
3392
3393 // Clean method data for this class
3394 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3395 if (k->is_instance_klass()) {
3396 InstanceKlass *ik = InstanceKlass::cast(k);
3397 // Clean MethodData of this class's methods so they don't refer to
3398 // old methods that are no longer running.
3399 Array<Method*>* methods = ik->methods();
3400 int num_methods = methods->length();
3401 for (int index = 0; index < num_methods; ++index) {
3402 if (methods->at(index)->method_data() != NULL) {
3403 methods->at(index)->method_data()->clean_weak_method_links();
3404 }
3405 }
3406 }
3407 }
3408
3409 void VM_RedefineClasses::update_jmethod_ids() {
3410 for (int j = 0; j < _matching_methods_length; ++j) {
3411 Method* old_method = _matching_old_methods[j];
3412 jmethodID jmid = old_method->find_jmethod_id_or_null();
3413 if (jmid != NULL) {
3414 // There is a jmethodID, change it to point to the new method
3415 methodHandle new_method_h(_matching_new_methods[j]);
3416 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3417 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3418 "should be replaced");
3419 }
3420 }
3421 }
3422
3423 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3424 int emcp_method_count = 0;
3425 int obsolete_count = 0;
3426 int old_index = 0;
3427 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3428 Method* old_method = _matching_old_methods[j];
3429 Method* new_method = _matching_new_methods[j];
3430 Method* old_array_method;
3431
3432 // Maintain an old_index into the _old_methods array by skipping
3433 // deleted methods
3434 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3435 ++old_index;
3436 }
3437
3438 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3439 // The EMCP definition from JSR-163 requires the bytecodes to be
3440 // the same with the exception of constant pool indices which may
3441 // differ. However, the constants referred to by those indices
3442 // must be the same.
3443 //
3444 // We use methods_EMCP() for comparison since constant pool
3445 // merging can remove duplicate constant pool entries that were
3446 // present in the old method and removed from the rewritten new
3447 // method. A faster binary comparison function would consider the
3448 // old and new methods to be different when they are actually
3449 // EMCP.
3450 //
3451 // The old and new methods are EMCP and you would think that we
3452 // could get rid of one of them here and now and save some space.
3453 // However, the concept of EMCP only considers the bytecodes and
3454 // the constant pool entries in the comparison. Other things,
3455 // e.g., the line number table (LNT) or the local variable table
3456 // (LVT) don't count in the comparison. So the new (and EMCP)
3457 // method can have a new LNT that we need so we can't just
3458 // overwrite the new method with the old method.
3459 //
3460 // When this routine is called, we have already attached the new
3461 // methods to the_class so the old methods are effectively
3462 // overwritten. However, if an old method is still executing,
3463 // then the old method cannot be collected until sometime after
3464 // the old method call has returned. So the overwriting of old
3465 // methods by new methods will save us space except for those
3466 // (hopefully few) old methods that are still executing.
3467 //
3468 // A method refers to a ConstMethod* and this presents another
3469 // possible avenue to space savings. The ConstMethod* in the
3470 // new method contains possibly new attributes (LNT, LVT, etc).
3471 // At first glance, it seems possible to save space by replacing
3472 // the ConstMethod* in the old method with the ConstMethod*
3473 // from the new method. The old and new methods would share the
3474 // same ConstMethod* and we would save the space occupied by
3475 // the old ConstMethod*. However, the ConstMethod* contains
3476 // a back reference to the containing method. Sharing the
3477 // ConstMethod* between two methods could lead to confusion in
3478 // the code that uses the back reference. This would lead to
3479 // brittle code that could be broken in non-obvious ways now or
3480 // in the future.
3481 //
3482 // Another possibility is to copy the ConstMethod* from the new
3483 // method to the old method and then overwrite the new method with
3484 // the old method. Since the ConstMethod* contains the bytecodes
3485 // for the method embedded in the oop, this option would change
3486 // the bytecodes out from under any threads executing the old
3487 // method and make the thread's bcp invalid. Since EMCP requires
3488 // that the bytecodes be the same modulo constant pool indices, it
3489 // is straight forward to compute the correct new bcp in the new
3490 // ConstMethod* from the old bcp in the old ConstMethod*. The
3491 // time consuming part would be searching all the frames in all
3492 // of the threads to find all of the calls to the old method.
3493 //
3494 // It looks like we will have to live with the limited savings
3495 // that we get from effectively overwriting the old methods
3496 // when the new methods are attached to the_class.
3497
3498 // Count number of methods that are EMCP. The method will be marked
3499 // old but not obsolete if it is EMCP.
3500 emcp_method_count++;
3501
3502 // An EMCP method is _not_ obsolete. An obsolete method has a
3503 // different jmethodID than the current method. An EMCP method
3504 // has the same jmethodID as the current method. Having the
3505 // same jmethodID for all EMCP versions of a method allows for
3506 // a consistent view of the EMCP methods regardless of which
3507 // EMCP method you happen to have in hand. For example, a
3508 // breakpoint set in one EMCP method will work for all EMCP
3509 // versions of the method including the current one.
3510 } else {
3511 // mark obsolete methods as such
3512 old_method->set_is_obsolete();
3513 obsolete_count++;
3514
3515 // obsolete methods need a unique idnum so they become new entries in
3516 // the jmethodID cache in InstanceKlass
3517 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3518 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3519 if (num != ConstMethod::UNSET_IDNUM) {
3520 old_method->set_method_idnum(num);
3521 }
3522
3523 // With tracing we try not to "yack" too much. The position of
3524 // this trace assumes there are fewer obsolete methods than
3525 // EMCP methods.
3526 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3527 ResourceMark rm;
3528 log_trace(redefine, class, obsolete, mark)
3529 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3530 }
3531 }
3532 old_method->set_is_old();
3533 }
3534 for (int i = 0; i < _deleted_methods_length; ++i) {
3535 Method* old_method = _deleted_methods[i];
3536
3537 assert(!old_method->has_vtable_index(),
3538 "cannot delete methods with vtable entries");;
3539
3540 // Mark all deleted methods as old, obsolete and deleted
3541 old_method->set_is_deleted();
3542 old_method->set_is_old();
3543 old_method->set_is_obsolete();
3544 ++obsolete_count;
3545 // With tracing we try not to "yack" too much. The position of
3546 // this trace assumes there are fewer obsolete methods than
3547 // EMCP methods.
3548 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3549 ResourceMark rm;
3550 log_trace(redefine, class, obsolete, mark)
3551 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3552 }
3553 }
3554 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3555 "sanity check");
3556 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3557 return emcp_method_count;
3558 }
3559
3560 // This internal class transfers the native function registration from old methods
3561 // to new methods. It is designed to handle both the simple case of unchanged
3562 // native methods and the complex cases of native method prefixes being added and/or
3563 // removed.
3564 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3565 //
3566 // This class is used after the new methods have been installed in "the_class".
3567 //
3568 // So, for example, the following must be handled. Where 'm' is a method and
3569 // a number followed by an underscore is a prefix.
3570 //
3571 // Old Name New Name
3572 // Simple transfer to new method m -> m
3573 // Add prefix m -> 1_m
3574 // Remove prefix 1_m -> m
3575 // Simultaneous add of prefixes m -> 3_2_1_m
3576 // Simultaneous removal of prefixes 3_2_1_m -> m
3577 // Simultaneous add and remove 1_m -> 2_m
3578 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3579 //
3580 class TransferNativeFunctionRegistration {
3581 private:
3582 InstanceKlass* the_class;
3583 int prefix_count;
3584 char** prefixes;
3585
3586 // Recursively search the binary tree of possibly prefixed method names.
3587 // Iteration could be used if all agents were well behaved. Full tree walk is
3588 // more resilent to agents not cleaning up intermediate methods.
3589 // Branch at each depth in the binary tree is:
3590 // (1) without the prefix.
3591 // (2) with the prefix.
3592 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3593 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3594 Symbol* signature) {
3595 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3596 if (name_symbol != NULL) {
3597 Method* method = the_class->lookup_method(name_symbol, signature);
3598 if (method != NULL) {
3599 // Even if prefixed, intermediate methods must exist.
3600 if (method->is_native()) {
3601 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3602 return method;
3603 }
3604 if (depth < prefix_count) {
3605 // Try applying further prefixes (other than this one).
3606 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3607 if (method != NULL) {
3608 return method; // found
3609 }
3610
3611 // Try adding this prefix to the method name and see if it matches
3612 // another method name.
3613 char* prefix = prefixes[depth];
3614 size_t prefix_len = strlen(prefix);
3615 size_t trial_len = name_len + prefix_len;
3616 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3617 strcpy(trial_name_str, prefix);
3618 strcat(trial_name_str, name_str);
3619 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3620 signature);
3621 if (method != NULL) {
3622 // If found along this branch, it was prefixed, mark as such
3623 method->set_is_prefixed_native();
3624 return method; // found
3625 }
3626 }
3627 }
3628 }
3629 return NULL; // This whole branch bore nothing
3630 }
3631
3632 // Return the method name with old prefixes stripped away.
3633 char* method_name_without_prefixes(Method* method) {
3634 Symbol* name = method->name();
3635 char* name_str = name->as_utf8();
3636
3637 // Old prefixing may be defunct, strip prefixes, if any.
3638 for (int i = prefix_count-1; i >= 0; i--) {
3639 char* prefix = prefixes[i];
3640 size_t prefix_len = strlen(prefix);
3641 if (strncmp(prefix, name_str, prefix_len) == 0) {
3642 name_str += prefix_len;
3643 }
3644 }
3645 return name_str;
3646 }
3647
3648 // Strip any prefixes off the old native method, then try to find a
3649 // (possibly prefixed) new native that matches it.
3650 Method* strip_and_search_for_new_native(Method* method) {
3651 ResourceMark rm;
3652 char* name_str = method_name_without_prefixes(method);
3653 return search_prefix_name_space(0, name_str, strlen(name_str),
3654 method->signature());
3655 }
3656
3657 public:
3658
3659 // Construct a native method transfer processor for this class.
3660 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3661 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3662
3663 the_class = _the_class;
3664 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3665 }
3666
3667 // Attempt to transfer any of the old or deleted methods that are native
3668 void transfer_registrations(Method** old_methods, int methods_length) {
3669 for (int j = 0; j < methods_length; j++) {
3670 Method* old_method = old_methods[j];
3671
3672 if (old_method->is_native() && old_method->has_native_function()) {
3673 Method* new_method = strip_and_search_for_new_native(old_method);
3674 if (new_method != NULL) {
3675 // Actually set the native function in the new method.
3676 // Redefine does not send events (except CFLH), certainly not this
3677 // behind the scenes re-registration.
3678 new_method->set_native_function(old_method->native_function(),
3679 !Method::native_bind_event_is_interesting);
3680 }
3681 }
3682 }
3683 }
3684 };
3685
3686 // Don't lose the association between a native method and its JNI function.
3687 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3688 TransferNativeFunctionRegistration transfer(the_class);
3689 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3690 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3691 }
3692
3693 // Deoptimize all compiled code that depends on this class.
3694 //
3695 // If the can_redefine_classes capability is obtained in the onload
3696 // phase then the compiler has recorded all dependencies from startup.
3697 // In that case we need only deoptimize and throw away all compiled code
3698 // that depends on the class.
3699 //
3700 // If can_redefine_classes is obtained sometime after the onload
3701 // phase then the dependency information may be incomplete. In that case
3702 // the first call to RedefineClasses causes all compiled code to be
3703 // thrown away. As can_redefine_classes has been obtained then
3704 // all future compilations will record dependencies so second and
3705 // subsequent calls to RedefineClasses need only throw away code
3706 // that depends on the class.
3707 //
3708 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3709 assert_locked_or_safepoint(Compile_lock);
3710
3711 // All dependencies have been recorded from startup or this is a second or
3712 // subsequent use of RedefineClasses
3713 if (JvmtiExport::all_dependencies_are_recorded()) {
3714 CodeCache::flush_evol_dependents_on(ik);
3715 } else {
3716 CodeCache::mark_all_nmethods_for_deoptimization();
3717
3718 ResourceMark rm(THREAD);
3719 DeoptimizationMarker dm;
3720
3721 // Deoptimize all activations depending on marked nmethods
3722 Deoptimization::deoptimize_dependents();
3723
3724 // Make the dependent methods not entrant
3725 CodeCache::make_marked_nmethods_not_entrant();
3726
3727 // From now on we know that the dependency information is complete
3728 JvmtiExport::set_all_dependencies_are_recorded(true);
3729 }
3730 }
3731
3732 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3733 Method* old_method;
3734 Method* new_method;
3735
3736 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3737 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3738 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3739 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3740
3741 _matching_methods_length = 0;
3742 _deleted_methods_length = 0;
3743 _added_methods_length = 0;
3744
3745 int nj = 0;
3746 int oj = 0;
3747 while (true) {
3748 if (oj >= _old_methods->length()) {
3749 if (nj >= _new_methods->length()) {
3750 break; // we've looked at everything, done
3751 }
3752 // New method at the end
3753 new_method = _new_methods->at(nj);
3754 _added_methods[_added_methods_length++] = new_method;
3755 ++nj;
3756 } else if (nj >= _new_methods->length()) {
3757 // Old method, at the end, is deleted
3758 old_method = _old_methods->at(oj);
3759 _deleted_methods[_deleted_methods_length++] = old_method;
3760 ++oj;
3761 } else {
3762 old_method = _old_methods->at(oj);
3763 new_method = _new_methods->at(nj);
3764 if (old_method->name() == new_method->name()) {
3765 if (old_method->signature() == new_method->signature()) {
3766 _matching_old_methods[_matching_methods_length ] = old_method;
3767 _matching_new_methods[_matching_methods_length++] = new_method;
3768 ++nj;
3769 ++oj;
3770 } else {
3771 // added overloaded have already been moved to the end,
3772 // so this is a deleted overloaded method
3773 _deleted_methods[_deleted_methods_length++] = old_method;
3774 ++oj;
3775 }
3776 } else { // names don't match
3777 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3778 // new method
3779 _added_methods[_added_methods_length++] = new_method;
3780 ++nj;
3781 } else {
3782 // deleted method
3783 _deleted_methods[_deleted_methods_length++] = old_method;
3784 ++oj;
3785 }
3786 }
3787 }
3788 }
3789 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3790 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3791 }
3792
3793
3794 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3795 InstanceKlass* scratch_class) {
3796 // Swap annotation fields values
3797 Annotations* old_annotations = the_class->annotations();
3798 the_class->set_annotations(scratch_class->annotations());
3799 scratch_class->set_annotations(old_annotations);
3800 }
3801
3802
3803 // Install the redefinition of a class:
3804 // - house keeping (flushing breakpoints and caches, deoptimizing
3805 // dependent compiled code)
3806 // - replacing parts in the_class with parts from scratch_class
3807 // - adding a weak reference to track the obsolete but interesting
3808 // parts of the_class
3809 // - adjusting constant pool caches and vtables in other classes
3810 // that refer to methods in the_class. These adjustments use the
3811 // ClassLoaderDataGraph::classes_do() facility which only allows
3812 // a helper method to be specified. The interesting parameters
3813 // that we would like to pass to the helper method are saved in
3814 // static global fields in the VM operation.
3815 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3816 InstanceKlass* scratch_class, TRAPS) {
3817
3818 HandleMark hm(THREAD); // make sure handles from this call are freed
3819
3820 if (log_is_enabled(Info, redefine, class, timer)) {
3821 _timer_rsc_phase1.start();
3822 }
3823
3824 InstanceKlass* the_class = get_ik(the_jclass);
3825
3826 // Remove all breakpoints in methods of this class
3827 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3828 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3829
3830 // Deoptimize all compiled code that depends on this class
3831 flush_dependent_code(the_class, THREAD);
3832
3833 _old_methods = the_class->methods();
3834 _new_methods = scratch_class->methods();
3835 _the_class = the_class;
3836 compute_added_deleted_matching_methods();
3837 update_jmethod_ids();
3838
3839 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
3840
3841 // Attach new constant pool to the original klass. The original
3842 // klass still refers to the old constant pool (for now).
3843 scratch_class->constants()->set_pool_holder(the_class);
3844
3845 #if 0
3846 // In theory, with constant pool merging in place we should be able
3847 // to save space by using the new, merged constant pool in place of
3848 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3849 // the klass version we are replacing now and any constant pool(s) in
3850 // previous versions of klass. Nice theory, doesn't work in practice.
3851 // When this code is enabled, even simple programs throw NullPointer
3852 // exceptions. I'm guessing that this is caused by some constant pool
3853 // cache difference between the new, merged constant pool and the
3854 // constant pool that was just being used by the klass. I'm keeping
3855 // this code around to archive the idea, but the code has to remain
3856 // disabled for now.
3857
3858 // Attach each old method to the new constant pool. This can be
3859 // done here since we are past the bytecode verification and
3860 // constant pool optimization phases.
3861 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3862 Method* method = _old_methods->at(i);
3863 method->set_constants(scratch_class->constants());
3864 }
3865
3866 // NOTE: this doesn't work because you can redefine the same class in two
3867 // threads, each getting their own constant pool data appended to the
3868 // original constant pool. In order for the new methods to work when they
3869 // become old methods, they need to keep their updated copy of the constant pool.
3870
3871 {
3872 // walk all previous versions of the klass
3873 InstanceKlass *ik = the_class;
3874 PreviousVersionWalker pvw(ik);
3875 do {
3876 ik = pvw.next_previous_version();
3877 if (ik != NULL) {
3878
3879 // attach previous version of klass to the new constant pool
3880 ik->set_constants(scratch_class->constants());
3881
3882 // Attach each method in the previous version of klass to the
3883 // new constant pool
3884 Array<Method*>* prev_methods = ik->methods();
3885 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3886 Method* method = prev_methods->at(i);
3887 method->set_constants(scratch_class->constants());
3888 }
3889 }
3890 } while (ik != NULL);
3891 }
3892 #endif
3893
3894 // Replace methods and constantpool
3895 the_class->set_methods(_new_methods);
3896 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3897 // and to be able to undo operation easily.
3898
3899 Array<int>* old_ordering = the_class->method_ordering();
3900 the_class->set_method_ordering(scratch_class->method_ordering());
3901 scratch_class->set_method_ordering(old_ordering);
3902
3903 ConstantPool* old_constants = the_class->constants();
3904 the_class->set_constants(scratch_class->constants());
3905 scratch_class->set_constants(old_constants); // See the previous comment.
3906 #if 0
3907 // We are swapping the guts of "the new class" with the guts of "the
3908 // class". Since the old constant pool has just been attached to "the
3909 // new class", it seems logical to set the pool holder in the old
3910 // constant pool also. However, doing this will change the observable
3911 // class hierarchy for any old methods that are still executing. A
3912 // method can query the identity of its "holder" and this query uses
3913 // the method's constant pool link to find the holder. The change in
3914 // holding class from "the class" to "the new class" can confuse
3915 // things.
3916 //
3917 // Setting the old constant pool's holder will also cause
3918 // verification done during vtable initialization below to fail.
3919 // During vtable initialization, the vtable's class is verified to be
3920 // a subtype of the method's holder. The vtable's class is "the
3921 // class" and the method's holder is gotten from the constant pool
3922 // link in the method itself. For "the class"'s directly implemented
3923 // methods, the method holder is "the class" itself (as gotten from
3924 // the new constant pool). The check works fine in this case. The
3925 // check also works fine for methods inherited from super classes.
3926 //
3927 // Miranda methods are a little more complicated. A miranda method is
3928 // provided by an interface when the class implementing the interface
3929 // does not provide its own method. These interfaces are implemented
3930 // internally as an InstanceKlass. These special instanceKlasses
3931 // share the constant pool of the class that "implements" the
3932 // interface. By sharing the constant pool, the method holder of a
3933 // miranda method is the class that "implements" the interface. In a
3934 // non-redefine situation, the subtype check works fine. However, if
3935 // the old constant pool's pool holder is modified, then the check
3936 // fails because there is no class hierarchy relationship between the
3937 // vtable's class and "the new class".
3938
3939 old_constants->set_pool_holder(scratch_class());
3940 #endif
3941
3942 // track number of methods that are EMCP for add_previous_version() call below
3943 int emcp_method_count = check_methods_and_mark_as_obsolete();
3944 transfer_old_native_function_registrations(the_class);
3945
3946 // The class file bytes from before any retransformable agents mucked
3947 // with them was cached on the scratch class, move to the_class.
3948 // Note: we still want to do this if nothing needed caching since it
3949 // should get cleared in the_class too.
3950 if (the_class->get_cached_class_file_bytes() == 0) {
3951 // the_class doesn't have a cache yet so copy it
3952 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3953 }
3954 else if (scratch_class->get_cached_class_file_bytes() !=
3955 the_class->get_cached_class_file_bytes()) {
3956 // The same class can be present twice in the scratch classes list or there
3957 // are multiple concurrent RetransformClasses calls on different threads.
3958 // In such cases we have to deallocate scratch_class cached_class_file.
3959 os::free(scratch_class->get_cached_class_file());
3960 }
3961
3962 // NULL out in scratch class to not delete twice. The class to be redefined
3963 // always owns these bytes.
3964 scratch_class->set_cached_class_file(NULL);
3965
3966 // Replace inner_classes
3967 Array<u2>* old_inner_classes = the_class->inner_classes();
3968 the_class->set_inner_classes(scratch_class->inner_classes());
3969 scratch_class->set_inner_classes(old_inner_classes);
3970
3971 // Initialize the vtable and interface table after
3972 // methods have been rewritten
3973 {
3974 ResourceMark rm(THREAD);
3975 // no exception should happen here since we explicitly
3976 // do not check loader constraints.
3977 // compare_and_normalize_class_versions has already checked:
3978 // - classloaders unchanged, signatures unchanged
3979 // - all instanceKlasses for redefined classes reused & contents updated
3980 the_class->vtable().initialize_vtable(false, THREAD);
3981 the_class->itable().initialize_itable(false, THREAD);
3982 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3983 }
3984
3985 // Leave arrays of jmethodIDs and itable index cache unchanged
3986
3987 // Copy the "source file name" attribute from new class version
3988 the_class->set_source_file_name_index(
3989 scratch_class->source_file_name_index());
3990
3991 // Copy the "source debug extension" attribute from new class version
3992 the_class->set_source_debug_extension(
3993 scratch_class->source_debug_extension(),
3994 scratch_class->source_debug_extension() == NULL ? 0 :
3995 (int)strlen(scratch_class->source_debug_extension()));
3996
3997 // Use of javac -g could be different in the old and the new
3998 if (scratch_class->access_flags().has_localvariable_table() !=
3999 the_class->access_flags().has_localvariable_table()) {
4000
4001 AccessFlags flags = the_class->access_flags();
4002 if (scratch_class->access_flags().has_localvariable_table()) {
4003 flags.set_has_localvariable_table();
4004 } else {
4005 flags.clear_has_localvariable_table();
4006 }
4007 the_class->set_access_flags(flags);
4008 }
4009
4010 swap_annotations(the_class, scratch_class);
4011
4012 // Replace minor version number of class file
4013 u2 old_minor_version = the_class->minor_version();
4014 the_class->set_minor_version(scratch_class->minor_version());
4015 scratch_class->set_minor_version(old_minor_version);
4016
4017 // Replace major version number of class file
4018 u2 old_major_version = the_class->major_version();
4019 the_class->set_major_version(scratch_class->major_version());
4020 scratch_class->set_major_version(old_major_version);
4021
4022 // Replace CP indexes for class and name+type of enclosing method
4023 u2 old_class_idx = the_class->enclosing_method_class_index();
4024 u2 old_method_idx = the_class->enclosing_method_method_index();
4025 the_class->set_enclosing_method_indices(
4026 scratch_class->enclosing_method_class_index(),
4027 scratch_class->enclosing_method_method_index());
4028 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4029
4030 // Replace fingerprint data
4031 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4032 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4033
4034 the_class->set_has_been_redefined();
4035
4036 if (!the_class->should_be_initialized()) {
4037 // Class was already initialized, so AOT has only seen the original version.
4038 // We need to let AOT look at it again.
4039 AOTLoader::load_for_klass(the_class, THREAD);
4040 }
4041
4042 // keep track of previous versions of this class
4043 the_class->add_previous_version(scratch_class, emcp_method_count);
4044
4045 _timer_rsc_phase1.stop();
4046 if (log_is_enabled(Info, redefine, class, timer)) {
4047 _timer_rsc_phase2.start();
4048 }
4049
4050 // Adjust constantpool caches and vtables for all classes
4051 // that reference methods of the evolved class.
4052 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4053 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4054
4055 if (the_class->oop_map_cache() != NULL) {
4056 // Flush references to any obsolete methods from the oop map cache
4057 // so that obsolete methods are not pinned.
4058 the_class->oop_map_cache()->flush_obsolete_entries();
4059 }
4060
4061 increment_class_counter((InstanceKlass *)the_class, THREAD);
4062 {
4063 ResourceMark rm(THREAD);
4064 // increment the classRedefinedCount field in the_class and in any
4065 // direct and indirect subclasses of the_class
4066 log_info(redefine, class, load)
4067 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4068 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4069 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4070 the_class->external_name(),
4071 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4072
4073 }
4074 _timer_rsc_phase2.stop();
4075 } // end redefine_single_class()
4076
4077
4078 // Increment the classRedefinedCount field in the specific InstanceKlass
4079 // and in all direct and indirect subclasses.
4080 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4081 oop class_mirror = ik->java_mirror();
4082 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4083 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4084 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4085
4086 if (class_oop != _the_class) {
4087 // _the_class count is printed at end of redefine_single_class()
4088 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4089 }
4090
4091 for (Klass *subk = ik->subklass(); subk != NULL;
4092 subk = subk->next_sibling()) {
4093 if (subk->is_instance_klass()) {
4094 // Only update instanceKlasses
4095 InstanceKlass *subik = InstanceKlass::cast(subk);
4096 // recursively do subclasses of the current subclass
4097 increment_class_counter(subik, THREAD);
4098 }
4099 }
4100 }
4101
4102 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4103 bool no_old_methods = true; // be optimistic
4104
4105 // Both array and instance classes have vtables.
4106 // a vtable should never contain old or obsolete methods
4107 ResourceMark rm(_thread);
4108 if (k->vtable_length() > 0 &&
4109 !k->vtable().check_no_old_or_obsolete_entries()) {
4110 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4111 log_trace(redefine, class, obsolete, metadata)
4112 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4113 k->signature_name());
4114 k->vtable().dump_vtable();
4115 }
4116 no_old_methods = false;
4117 }
4118
4119 if (k->is_instance_klass()) {
4120 HandleMark hm(_thread);
4121 InstanceKlass *ik = InstanceKlass::cast(k);
4122
4123 // an itable should never contain old or obsolete methods
4124 if (ik->itable_length() > 0 &&
4125 !ik->itable().check_no_old_or_obsolete_entries()) {
4126 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4127 log_trace(redefine, class, obsolete, metadata)
4128 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4129 ik->signature_name());
4130 ik->itable().dump_itable();
4131 }
4132 no_old_methods = false;
4133 }
4134
4135 // the constant pool cache should never contain non-deleted old or obsolete methods
4136 if (ik->constants() != NULL &&
4137 ik->constants()->cache() != NULL &&
4138 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4139 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4140 log_trace(redefine, class, obsolete, metadata)
4141 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4142 ik->signature_name());
4143 ik->constants()->cache()->dump_cache();
4144 }
4145 no_old_methods = false;
4146 }
4147 }
4148
4149 // print and fail guarantee if old methods are found.
4150 if (!no_old_methods) {
4151 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4152 dump_methods();
4153 } else {
4154 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4155 "to see more info about the following guarantee() failure.");
4156 }
4157 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4158 }
4159 }
4160
4161
4162 void VM_RedefineClasses::dump_methods() {
4163 int j;
4164 log_trace(redefine, class, dump)("_old_methods --");
4165 for (j = 0; j < _old_methods->length(); ++j) {
4166 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4167 Method* m = _old_methods->at(j);
4168 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4169 m->access_flags().print_on(&log_stream);
4170 log_stream.print(" -- ");
4171 m->print_name(&log_stream);
4172 log_stream.cr();
4173 }
4174 log_trace(redefine, class, dump)("_new_methods --");
4175 for (j = 0; j < _new_methods->length(); ++j) {
4176 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4177 Method* m = _new_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)("_matching_methods --");
4185 for (j = 0; j < _matching_methods_length; ++j) {
4186 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4187 Method* m = _matching_old_methods[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();
4192 log_stream.cr();
4193
4194 m = _matching_new_methods[j];
4195 log_stream.print(" (%5d) ", m->vtable_index());
4196 m->access_flags().print_on(&log_stream);
4197 log_stream.cr();
4198 }
4199 log_trace(redefine, class, dump)("_deleted_methods --");
4200 for (j = 0; j < _deleted_methods_length; ++j) {
4201 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4202 Method* m = _deleted_methods[j];
4203 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4204 m->access_flags().print_on(&log_stream);
4205 log_stream.print(" -- ");
4206 m->print_name(&log_stream);
4207 log_stream.cr();
4208 }
4209 log_trace(redefine, class, dump)("_added_methods --");
4210 for (j = 0; j < _added_methods_length; ++j) {
4211 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4212 Method* m = _added_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 }
4220
4221 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4222 VM_Operation::print_on_error(st);
4223 if (_the_class != NULL) {
4224 ResourceMark rm;
4225 st->print_cr(", redefining class %s", _the_class->external_name());
4226 }
4227 }