1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/metadataOnStackMark.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/verifier.hpp"
31 #include "code/codeCache.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "interpreter/rewriter.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/metadataFactory.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "memory/universe.hpp"
41 #include "oops/fieldStreams.hpp"
42 #include "oops/klassVtable.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "prims/jvmtiImpl.hpp"
45 #include "prims/jvmtiRedefineClasses.hpp"
46 #include "prims/jvmtiThreadState.inline.hpp"
47 #include "prims/resolvedMethodTable.hpp"
48 #include "prims/methodComparator.hpp"
49 #include "runtime/deoptimization.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/jniHandles.inline.hpp"
52 #include "runtime/relocator.hpp"
53 #include "utilities/bitMap.inline.hpp"
54 #include "utilities/events.hpp"
55
56 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
57 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
58 Method** VM_RedefineClasses::_matching_old_methods = NULL;
59 Method** VM_RedefineClasses::_matching_new_methods = NULL;
60 Method** VM_RedefineClasses::_deleted_methods = NULL;
61 Method** VM_RedefineClasses::_added_methods = NULL;
62 int VM_RedefineClasses::_matching_methods_length = 0;
63 int VM_RedefineClasses::_deleted_methods_length = 0;
64 int VM_RedefineClasses::_added_methods_length = 0;
65 Klass* VM_RedefineClasses::_the_class = NULL;
66
67
68 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
69 const jvmtiClassDefinition *class_defs,
70 JvmtiClassLoadKind class_load_kind) {
71 _class_count = class_count;
72 _class_defs = class_defs;
73 _class_load_kind = class_load_kind;
74 _any_class_has_resolved_methods = false;
75 _res = JVMTI_ERROR_NONE;
76 }
77
78 static inline InstanceKlass* get_ik(jclass def) {
79 oop mirror = JNIHandles::resolve_non_null(def);
80 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
81 }
82
83 // If any of the classes are being redefined, wait
84 // Parallel constant pool merging leads to indeterminate constant pools.
85 void VM_RedefineClasses::lock_classes() {
86 MutexLocker ml(RedefineClasses_lock);
87 bool has_redefined;
88 do {
89 has_redefined = false;
90 // Go through classes each time until none are being redefined.
91 for (int i = 0; i < _class_count; i++) {
92 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
93 RedefineClasses_lock->wait();
94 has_redefined = true;
95 break; // for loop
96 }
97 }
98 } while (has_redefined);
99 for (int i = 0; i < _class_count; i++) {
100 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
101 }
102 RedefineClasses_lock->notify_all();
103 }
104
105 void VM_RedefineClasses::unlock_classes() {
106 MutexLocker ml(RedefineClasses_lock);
107 for (int i = 0; i < _class_count; i++) {
108 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
109 "should be being redefined to get here");
110 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
111 }
112 RedefineClasses_lock->notify_all();
113 }
114
115 bool VM_RedefineClasses::doit_prologue() {
116 if (_class_count == 0) {
117 _res = JVMTI_ERROR_NONE;
118 return false;
119 }
120 if (_class_defs == NULL) {
121 _res = JVMTI_ERROR_NULL_POINTER;
122 return false;
123 }
124 for (int i = 0; i < _class_count; i++) {
125 if (_class_defs[i].klass == NULL) {
126 _res = JVMTI_ERROR_INVALID_CLASS;
127 return false;
128 }
129 if (_class_defs[i].class_byte_count == 0) {
130 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
131 return false;
132 }
133 if (_class_defs[i].class_bytes == NULL) {
134 _res = JVMTI_ERROR_NULL_POINTER;
135 return false;
136 }
137
138 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
139 // classes for primitives and arrays and vm anonymous classes cannot be redefined
140 // check here so following code can assume these classes are InstanceKlass
141 if (!is_modifiable_class(mirror)) {
142 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
143 return false;
144 }
145 }
146
147 // Start timer after all the sanity checks; not quite accurate, but
148 // better than adding a bunch of stop() calls.
149 if (log_is_enabled(Info, redefine, class, timer)) {
150 _timer_vm_op_prologue.start();
151 }
152
153 lock_classes();
154 // We first load new class versions in the prologue, because somewhere down the
155 // call chain it is required that the current thread is a Java thread.
156 _res = load_new_class_versions(Thread::current());
157 if (_res != JVMTI_ERROR_NONE) {
158 // free any successfully created classes, since none are redefined
159 for (int i = 0; i < _class_count; i++) {
160 if (_scratch_classes[i] != NULL) {
161 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
162 // Free the memory for this class at class unloading time. Not before
163 // because CMS might think this is still live.
164 InstanceKlass* ik = get_ik(_class_defs[i].klass);
165 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
166 // Don't double-free cached_class_file copied from the original class if error.
167 _scratch_classes[i]->set_cached_class_file(NULL);
168 }
169 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
170 }
171 }
172 // Free os::malloc allocated memory in load_new_class_version.
173 os::free(_scratch_classes);
174 _timer_vm_op_prologue.stop();
175 unlock_classes();
176 return false;
177 }
178
179 _timer_vm_op_prologue.stop();
180 return true;
181 }
182
183 void VM_RedefineClasses::doit() {
184 Thread *thread = Thread::current();
185
186 #if INCLUDE_CDS
187 if (UseSharedSpaces) {
188 // Sharing is enabled so we remap the shared readonly space to
189 // shared readwrite, private just in case we need to redefine
190 // a shared class. We do the remap during the doit() phase of
191 // the safepoint to be safer.
192 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
193 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
194 _res = JVMTI_ERROR_INTERNAL;
195 return;
196 }
197 }
198 #endif
199
200 // Mark methods seen on stack and everywhere else so old methods are not
201 // cleaned up if they're on the stack.
202 MetadataOnStackMark md_on_stack(true);
203 HandleMark hm(thread); // make sure any handles created are deleted
204 // before the stack walk again.
205
206 for (int i = 0; i < _class_count; i++) {
207 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
208 }
209
210 // Clean out MethodData pointing to old Method*
211 // Have to do this after all classes are redefined and all methods that
212 // are redefined are marked as old.
213 MethodDataCleaner clean_weak_method_links;
214 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
215
216 // JSR-292 support
217 if (_any_class_has_resolved_methods) {
218 bool trace_name_printed = false;
219 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
220 }
221
222 // Disable any dependent concurrent compilations
223 SystemDictionary::notice_modification();
224
225 // Set flag indicating that some invariants are no longer true.
226 // See jvmtiExport.hpp for detailed explanation.
227 JvmtiExport::set_has_redefined_a_class();
228
229 // check_class() is optionally called for product bits, but is
230 // always called for non-product bits.
231 #ifdef PRODUCT
232 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
233 #endif
234 log_trace(redefine, class, obsolete, metadata)("calling check_class");
235 CheckClass check_class(thread);
236 ClassLoaderDataGraph::classes_do(&check_class);
237 #ifdef PRODUCT
238 }
239 #endif
240 }
241
242 void VM_RedefineClasses::doit_epilogue() {
243 unlock_classes();
244
245 // Free os::malloc allocated memory.
246 os::free(_scratch_classes);
247
248 // Reset the_class to null for error printing.
249 _the_class = NULL;
250
251 if (log_is_enabled(Info, redefine, class, timer)) {
252 // Used to have separate timers for "doit" and "all", but the timer
253 // overhead skewed the measurements.
254 julong doit_time = _timer_rsc_phase1.milliseconds() +
255 _timer_rsc_phase2.milliseconds();
256 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
257
258 log_info(redefine, class, timer)
259 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
260 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
261 log_info(redefine, class, timer)
262 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
263 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
264 }
265 }
266
267 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
268 // classes for primitives cannot be redefined
269 if (java_lang_Class::is_primitive(klass_mirror)) {
270 return false;
271 }
272 Klass* k = java_lang_Class::as_Klass(klass_mirror);
273 // classes for arrays cannot be redefined
274 if (k == NULL || !k->is_instance_klass()) {
275 return false;
276 }
277
278 // Cannot redefine or retransform an anonymous class.
279 if (InstanceKlass::cast(k)->is_anonymous()) {
280 return false;
281 }
282 return true;
283 }
284
285 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
286 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
287 // direct CP entries, there is just the current entry to append. For
288 // indirect and double-indirect CP entries, there are zero or more
289 // referenced CP entries along with the current entry to append.
290 // Indirect and double-indirect CP entries are handled by recursive
291 // calls to append_entry() as needed. The referenced CP entries are
292 // always appended to *merge_cp_p before the referee CP entry. These
293 // referenced CP entries may already exist in *merge_cp_p in which case
294 // there is nothing extra to append and only the current entry is
295 // appended.
296 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
297 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
298 TRAPS) {
299
300 // append is different depending on entry tag type
301 switch (scratch_cp->tag_at(scratch_i).value()) {
302
303 // The old verifier is implemented outside the VM. It loads classes,
304 // but does not resolve constant pool entries directly so we never
305 // see Class entries here with the old verifier. Similarly the old
306 // verifier does not like Class entries in the input constant pool.
307 // The split-verifier is implemented in the VM so it can optionally
308 // and directly resolve constant pool entries to load classes. The
309 // split-verifier can accept either Class entries or UnresolvedClass
310 // entries in the input constant pool. We revert the appended copy
311 // back to UnresolvedClass so that either verifier will be happy
312 // with the constant pool entry.
313 //
314 // this is an indirect CP entry so it needs special handling
315 case JVM_CONSTANT_Class:
316 case JVM_CONSTANT_UnresolvedClass:
317 {
318 int name_i = scratch_cp->klass_name_index_at(scratch_i);
319 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
320 merge_cp_length_p, THREAD);
321
322 if (new_name_i != name_i) {
323 log_trace(redefine, class, constantpool)
324 ("Class entry@%d name_index change: %d to %d",
325 *merge_cp_length_p, name_i, new_name_i);
326 }
327
328 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
329 if (scratch_i != *merge_cp_length_p) {
330 // The new entry in *merge_cp_p is at a different index than
331 // the new entry in scratch_cp so we need to map the index values.
332 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
333 }
334 (*merge_cp_length_p)++;
335 } break;
336
337 // these are direct CP entries so they can be directly appended,
338 // but double and long take two constant pool entries
339 case JVM_CONSTANT_Double: // fall through
340 case JVM_CONSTANT_Long:
341 {
342 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
343 THREAD);
344
345 if (scratch_i != *merge_cp_length_p) {
346 // The new entry in *merge_cp_p is at a different index than
347 // the new entry in scratch_cp so we need to map the index values.
348 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
349 }
350 (*merge_cp_length_p) += 2;
351 } break;
352
353 // these are direct CP entries so they can be directly appended
354 case JVM_CONSTANT_Float: // fall through
355 case JVM_CONSTANT_Integer: // fall through
356 case JVM_CONSTANT_Utf8: // fall through
357
358 // This was an indirect CP entry, but it has been changed into
359 // Symbol*s so this entry can be directly appended.
360 case JVM_CONSTANT_String: // fall through
361 {
362 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
363 THREAD);
364
365 if (scratch_i != *merge_cp_length_p) {
366 // The new entry in *merge_cp_p is at a different index than
367 // the new entry in scratch_cp so we need to map the index values.
368 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
369 }
370 (*merge_cp_length_p)++;
371 } break;
372
373 // this is an indirect CP entry so it needs special handling
374 case JVM_CONSTANT_NameAndType:
375 {
376 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
377 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
378 merge_cp_length_p, THREAD);
379
380 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
381 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
382 merge_cp_p, merge_cp_length_p,
383 THREAD);
384
385 // If the referenced entries already exist in *merge_cp_p, then
386 // both new_name_ref_i and new_signature_ref_i will both be 0.
387 // In that case, all we are appending is the current entry.
388 if (new_name_ref_i != name_ref_i) {
389 log_trace(redefine, class, constantpool)
390 ("NameAndType entry@%d name_ref_index change: %d to %d",
391 *merge_cp_length_p, name_ref_i, new_name_ref_i);
392 }
393 if (new_signature_ref_i != signature_ref_i) {
394 log_trace(redefine, class, constantpool)
395 ("NameAndType entry@%d signature_ref_index change: %d to %d",
396 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
397 }
398
399 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
400 new_name_ref_i, new_signature_ref_i);
401 if (scratch_i != *merge_cp_length_p) {
402 // The new entry in *merge_cp_p is at a different index than
403 // the new entry in scratch_cp so we need to map the index values.
404 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
405 }
406 (*merge_cp_length_p)++;
407 } break;
408
409 // this is a double-indirect CP entry so it needs special handling
410 case JVM_CONSTANT_Fieldref: // fall through
411 case JVM_CONSTANT_InterfaceMethodref: // fall through
412 case JVM_CONSTANT_Methodref:
413 {
414 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
415 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
416 merge_cp_p, merge_cp_length_p, THREAD);
417
418 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
419 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
420 merge_cp_p, merge_cp_length_p, THREAD);
421
422 const char *entry_name = NULL;
423 switch (scratch_cp->tag_at(scratch_i).value()) {
424 case JVM_CONSTANT_Fieldref:
425 entry_name = "Fieldref";
426 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
427 new_name_and_type_ref_i);
428 break;
429 case JVM_CONSTANT_InterfaceMethodref:
430 entry_name = "IFMethodref";
431 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
432 new_klass_ref_i, new_name_and_type_ref_i);
433 break;
434 case JVM_CONSTANT_Methodref:
435 entry_name = "Methodref";
436 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
437 new_name_and_type_ref_i);
438 break;
439 default:
440 guarantee(false, "bad switch");
441 break;
442 }
443
444 if (klass_ref_i != new_klass_ref_i) {
445 log_trace(redefine, class, constantpool)
446 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
447 }
448 if (name_and_type_ref_i != new_name_and_type_ref_i) {
449 log_trace(redefine, class, constantpool)
450 ("%s entry@%d name_and_type_index changed: %d to %d",
451 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
452 }
453
454 if (scratch_i != *merge_cp_length_p) {
455 // The new entry in *merge_cp_p is at a different index than
456 // the new entry in scratch_cp so we need to map the index values.
457 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
458 }
459 (*merge_cp_length_p)++;
460 } break;
461
462 // this is an indirect CP entry so it needs special handling
463 case JVM_CONSTANT_MethodType:
464 {
465 int ref_i = scratch_cp->method_type_index_at(scratch_i);
466 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
467 merge_cp_length_p, THREAD);
468 if (new_ref_i != ref_i) {
469 log_trace(redefine, class, constantpool)
470 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
471 }
472 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
473 if (scratch_i != *merge_cp_length_p) {
474 // The new entry in *merge_cp_p is at a different index than
475 // the new entry in scratch_cp so we need to map the index values.
476 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
477 }
478 (*merge_cp_length_p)++;
479 } break;
480
481 // this is an indirect CP entry so it needs special handling
482 case JVM_CONSTANT_MethodHandle:
483 {
484 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
485 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
486 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
487 merge_cp_length_p, THREAD);
488 if (new_ref_i != ref_i) {
489 log_trace(redefine, class, constantpool)
490 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
491 }
492 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
493 if (scratch_i != *merge_cp_length_p) {
494 // The new entry in *merge_cp_p is at a different index than
495 // the new entry in scratch_cp so we need to map the index values.
496 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
497 }
498 (*merge_cp_length_p)++;
499 } break;
500
501 // this is an indirect CP entry so it needs special handling
502 case JVM_CONSTANT_Dynamic: // fall through
503 case JVM_CONSTANT_InvokeDynamic:
504 {
505 // Index of the bootstrap specifier in the operands array
506 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
507 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
508 merge_cp_length_p, THREAD);
509 // The bootstrap method NameAndType_info index
510 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
511 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
512 merge_cp_length_p, THREAD);
513 if (new_bs_i != old_bs_i) {
514 log_trace(redefine, class, constantpool)
515 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
516 *merge_cp_length_p, old_bs_i, new_bs_i);
517 }
518 if (new_ref_i != old_ref_i) {
519 log_trace(redefine, class, constantpool)
520 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
521 }
522
523 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
524 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
525 else
526 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
527 if (scratch_i != *merge_cp_length_p) {
528 // The new entry in *merge_cp_p is at a different index than
529 // the new entry in scratch_cp so we need to map the index values.
530 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
531 }
532 (*merge_cp_length_p)++;
533 } break;
534
535 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
536 // ClassIndex
537 case JVM_CONSTANT_ClassIndex: // fall through
538
539 // Invalid is used as the tag for the second constant pool entry
540 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
541 // not be seen by itself.
542 case JVM_CONSTANT_Invalid: // fall through
543
544 // At this stage, String could be here, but not StringIndex
545 case JVM_CONSTANT_StringIndex: // fall through
546
547 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
548 // here
549 case JVM_CONSTANT_UnresolvedClassInError: // fall through
550
551 default:
552 {
553 // leave a breadcrumb
554 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
555 ShouldNotReachHere();
556 } break;
557 } // end switch tag value
558 } // end append_entry()
559
560
561 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
562 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
563
564 int new_ref_i = ref_i;
565 bool match = (ref_i < *merge_cp_length_p) &&
566 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
567
568 if (!match) {
569 // forward reference in *merge_cp_p or not a direct match
570 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
571 if (found_i != 0) {
572 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
573 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
574 new_ref_i = found_i;
575 map_index(scratch_cp, ref_i, found_i);
576 } else {
577 // no match found so we have to append this entry to *merge_cp_p
578 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
579 // The above call to append_entry() can only append one entry
580 // so the post call query of *merge_cp_length_p is only for
581 // the sake of consistency.
582 new_ref_i = *merge_cp_length_p - 1;
583 }
584 }
585
586 return new_ref_i;
587 } // end find_or_append_indirect_entry()
588
589
590 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
591 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
592 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
593 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
594 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
595
596 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
597 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
598 merge_cp_length_p, THREAD);
599 if (new_ref_i != old_ref_i) {
600 log_trace(redefine, class, constantpool)
601 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
602 }
603
604 Array<u2>* merge_ops = (*merge_cp_p)->operands();
605 int new_bs_i = _operands_cur_length;
606 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
607 // However, the operand_offset_at(0) was set in the extend_operands() call.
608 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
609 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
610 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
611
612 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
613 merge_ops->at_put(new_base++, new_ref_i);
614 merge_ops->at_put(new_base++, argc);
615
616 for (int i = 0; i < argc; i++) {
617 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
618 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
619 merge_cp_length_p, THREAD);
620 merge_ops->at_put(new_base++, new_arg_ref_i);
621 if (new_arg_ref_i != old_arg_ref_i) {
622 log_trace(redefine, class, constantpool)
623 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
624 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
625 }
626 }
627 if (old_bs_i != _operands_cur_length) {
628 // The bootstrap specifier in *merge_cp_p is at a different index than
629 // that in scratch_cp so we need to map the index values.
630 map_operand_index(old_bs_i, new_bs_i);
631 }
632 _operands_cur_length++;
633 } // end append_operand()
634
635
636 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
637 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
638
639 int new_bs_i = old_bs_i; // bootstrap specifier index
640 bool match = (old_bs_i < _operands_cur_length) &&
641 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
642
643 if (!match) {
644 // forward reference in *merge_cp_p or not a direct match
645 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
646 _operands_cur_length, THREAD);
647 if (found_i != -1) {
648 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
649 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
650 new_bs_i = found_i;
651 map_operand_index(old_bs_i, found_i);
652 } else {
653 // no match found so we have to append this bootstrap specifier to *merge_cp_p
654 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
655 new_bs_i = _operands_cur_length - 1;
656 }
657 }
658 return new_bs_i;
659 } // end find_or_append_operand()
660
661
662 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
663 if (merge_cp->operands() == NULL) {
664 return;
665 }
666 // Shrink the merge_cp operands
667 merge_cp->shrink_operands(_operands_cur_length, CHECK);
668
669 if (log_is_enabled(Trace, redefine, class, constantpool)) {
670 // don't want to loop unless we are tracing
671 int count = 0;
672 for (int i = 1; i < _operands_index_map_p->length(); i++) {
673 int value = _operands_index_map_p->at(i);
674 if (value != -1) {
675 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
676 count++;
677 }
678 }
679 }
680 // Clean-up
681 _operands_index_map_p = NULL;
682 _operands_cur_length = 0;
683 _operands_index_map_count = 0;
684 } // end finalize_operands_merge()
685
686
687 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
688 InstanceKlass* the_class,
689 InstanceKlass* scratch_class) {
690 int i;
691
692 // Check superclasses, or rather their names, since superclasses themselves can be
693 // requested to replace.
694 // Check for NULL superclass first since this might be java.lang.Object
695 if (the_class->super() != scratch_class->super() &&
696 (the_class->super() == NULL || scratch_class->super() == NULL ||
697 the_class->super()->name() !=
698 scratch_class->super()->name())) {
699 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
700 }
701
702 // Check if the number, names and order of directly implemented interfaces are the same.
703 // I think in principle we should just check if the sets of names of directly implemented
704 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
705 // .java file, also changes in .class file) should not matter. However, comparing sets is
706 // technically a bit more difficult, and, more importantly, I am not sure at present that the
707 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
708 // rely on it somewhere.
709 Array<Klass*>* k_interfaces = the_class->local_interfaces();
710 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
711 int n_intfs = k_interfaces->length();
712 if (n_intfs != k_new_interfaces->length()) {
713 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
714 }
715 for (i = 0; i < n_intfs; i++) {
716 if (k_interfaces->at(i)->name() !=
717 k_new_interfaces->at(i)->name()) {
718 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
719 }
720 }
721
722 // Check whether class is in the error init state.
723 if (the_class->is_in_error_state()) {
724 // TBD #5057930: special error code is needed in 1.6
725 return JVMTI_ERROR_INVALID_CLASS;
726 }
727
728 // Check whether class modifiers are the same.
729 jushort old_flags = (jushort) the_class->access_flags().get_flags();
730 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
731 if (old_flags != new_flags) {
732 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
733 }
734
735 // Check if the number, names, types and order of fields declared in these classes
736 // are the same.
737 JavaFieldStream old_fs(the_class);
738 JavaFieldStream new_fs(scratch_class);
739 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
740 // access
741 old_flags = old_fs.access_flags().as_short();
742 new_flags = new_fs.access_flags().as_short();
743 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
744 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
745 }
746 // offset
747 if (old_fs.offset() != new_fs.offset()) {
748 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
749 }
750 // name and signature
751 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
752 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
753 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
754 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
755 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
756 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
757 }
758 }
759
760 // If both streams aren't done then we have a differing number of
761 // fields.
762 if (!old_fs.done() || !new_fs.done()) {
763 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
764 }
765
766 // Do a parallel walk through the old and new methods. Detect
767 // cases where they match (exist in both), have been added in
768 // the new methods, or have been deleted (exist only in the
769 // old methods). The class file parser places methods in order
770 // by method name, but does not order overloaded methods by
771 // signature. In order to determine what fate befell the methods,
772 // this code places the overloaded new methods that have matching
773 // old methods in the same order as the old methods and places
774 // new overloaded methods at the end of overloaded methods of
775 // that name. The code for this order normalization is adapted
776 // from the algorithm used in InstanceKlass::find_method().
777 // Since we are swapping out of order entries as we find them,
778 // we only have to search forward through the overloaded methods.
779 // Methods which are added and have the same name as an existing
780 // method (but different signature) will be put at the end of
781 // the methods with that name, and the name mismatch code will
782 // handle them.
783 Array<Method*>* k_old_methods(the_class->methods());
784 Array<Method*>* k_new_methods(scratch_class->methods());
785 int n_old_methods = k_old_methods->length();
786 int n_new_methods = k_new_methods->length();
787 Thread* thread = Thread::current();
788
789 int ni = 0;
790 int oi = 0;
791 while (true) {
792 Method* k_old_method;
793 Method* k_new_method;
794 enum { matched, added, deleted, undetermined } method_was = undetermined;
795
796 if (oi >= n_old_methods) {
797 if (ni >= n_new_methods) {
798 break; // we've looked at everything, done
799 }
800 // New method at the end
801 k_new_method = k_new_methods->at(ni);
802 method_was = added;
803 } else if (ni >= n_new_methods) {
804 // Old method, at the end, is deleted
805 k_old_method = k_old_methods->at(oi);
806 method_was = deleted;
807 } else {
808 // There are more methods in both the old and new lists
809 k_old_method = k_old_methods->at(oi);
810 k_new_method = k_new_methods->at(ni);
811 if (k_old_method->name() != k_new_method->name()) {
812 // Methods are sorted by method name, so a mismatch means added
813 // or deleted
814 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
815 method_was = added;
816 } else {
817 method_was = deleted;
818 }
819 } else if (k_old_method->signature() == k_new_method->signature()) {
820 // Both the name and signature match
821 method_was = matched;
822 } else {
823 // The name matches, but the signature doesn't, which means we have to
824 // search forward through the new overloaded methods.
825 int nj; // outside the loop for post-loop check
826 for (nj = ni + 1; nj < n_new_methods; nj++) {
827 Method* m = k_new_methods->at(nj);
828 if (k_old_method->name() != m->name()) {
829 // reached another method name so no more overloaded methods
830 method_was = deleted;
831 break;
832 }
833 if (k_old_method->signature() == m->signature()) {
834 // found a match so swap the methods
835 k_new_methods->at_put(ni, m);
836 k_new_methods->at_put(nj, k_new_method);
837 k_new_method = m;
838 method_was = matched;
839 break;
840 }
841 }
842
843 if (nj >= n_new_methods) {
844 // reached the end without a match; so method was deleted
845 method_was = deleted;
846 }
847 }
848 }
849
850 switch (method_was) {
851 case matched:
852 // methods match, be sure modifiers do too
853 old_flags = (jushort) k_old_method->access_flags().get_flags();
854 new_flags = (jushort) k_new_method->access_flags().get_flags();
855 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
856 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
857 }
858 {
859 u2 new_num = k_new_method->method_idnum();
860 u2 old_num = k_old_method->method_idnum();
861 if (new_num != old_num) {
862 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
863 if (idnum_owner != NULL) {
864 // There is already a method assigned this idnum -- switch them
865 // Take current and original idnum from the new_method
866 idnum_owner->set_method_idnum(new_num);
867 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
868 }
869 // Take current and original idnum from the old_method
870 k_new_method->set_method_idnum(old_num);
871 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
872 if (thread->has_pending_exception()) {
873 return JVMTI_ERROR_OUT_OF_MEMORY;
874 }
875 }
876 }
877 log_trace(redefine, class, normalize)
878 ("Method matched: new: %s [%d] == old: %s [%d]",
879 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
880 // advance to next pair of methods
881 ++oi;
882 ++ni;
883 break;
884 case added:
885 // method added, see if it is OK
886 new_flags = (jushort) k_new_method->access_flags().get_flags();
887 if ((new_flags & JVM_ACC_PRIVATE) == 0
888 // hack: private should be treated as final, but alas
889 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
890 ) {
891 // new methods must be private
892 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
893 }
894 {
895 u2 num = the_class->next_method_idnum();
896 if (num == ConstMethod::UNSET_IDNUM) {
897 // cannot add any more methods
898 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
899 }
900 u2 new_num = k_new_method->method_idnum();
901 Method* idnum_owner = scratch_class->method_with_idnum(num);
902 if (idnum_owner != NULL) {
903 // There is already a method assigned this idnum -- switch them
904 // Take current and original idnum from the new_method
905 idnum_owner->set_method_idnum(new_num);
906 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
907 }
908 k_new_method->set_method_idnum(num);
909 k_new_method->set_orig_method_idnum(num);
910 if (thread->has_pending_exception()) {
911 return JVMTI_ERROR_OUT_OF_MEMORY;
912 }
913 }
914 log_trace(redefine, class, normalize)
915 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
916 ++ni; // advance to next new method
917 break;
918 case deleted:
919 // method deleted, see if it is OK
920 old_flags = (jushort) k_old_method->access_flags().get_flags();
921 if ((old_flags & JVM_ACC_PRIVATE) == 0
922 // hack: private should be treated as final, but alas
923 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
924 ) {
925 // deleted methods must be private
926 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
927 }
928 log_trace(redefine, class, normalize)
929 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
930 ++oi; // advance to next old method
931 break;
932 default:
933 ShouldNotReachHere();
934 }
935 }
936
937 return JVMTI_ERROR_NONE;
938 }
939
940
941 // Find new constant pool index value for old constant pool index value
942 // by seaching the index map. Returns zero (0) if there is no mapped
943 // value for the old constant pool index.
944 int VM_RedefineClasses::find_new_index(int old_index) {
945 if (_index_map_count == 0) {
946 // map is empty so nothing can be found
947 return 0;
948 }
949
950 if (old_index < 1 || old_index >= _index_map_p->length()) {
951 // The old_index is out of range so it is not mapped. This should
952 // not happen in regular constant pool merging use, but it can
953 // happen if a corrupt annotation is processed.
954 return 0;
955 }
956
957 int value = _index_map_p->at(old_index);
958 if (value == -1) {
959 // the old_index is not mapped
960 return 0;
961 }
962
963 return value;
964 } // end find_new_index()
965
966
967 // Find new bootstrap specifier index value for old bootstrap specifier index
968 // value by seaching the index map. Returns unused index (-1) if there is
969 // no mapped value for the old bootstrap specifier index.
970 int VM_RedefineClasses::find_new_operand_index(int old_index) {
971 if (_operands_index_map_count == 0) {
972 // map is empty so nothing can be found
973 return -1;
974 }
975
976 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
977 // The old_index is out of range so it is not mapped.
978 // This should not happen in regular constant pool merging use.
979 return -1;
980 }
981
982 int value = _operands_index_map_p->at(old_index);
983 if (value == -1) {
984 // the old_index is not mapped
985 return -1;
986 }
987
988 return value;
989 } // end find_new_operand_index()
990
991
992 // Returns true if the current mismatch is due to a resolved/unresolved
993 // class pair. Otherwise, returns false.
994 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
995 int index1, const constantPoolHandle& cp2, int index2) {
996
997 jbyte t1 = cp1->tag_at(index1).value();
998 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
999 return false; // wrong entry type; not our special case
1000 }
1001
1002 jbyte t2 = cp2->tag_at(index2).value();
1003 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1004 return false; // wrong entry type; not our special case
1005 }
1006
1007 if (t1 == t2) {
1008 return false; // not a mismatch; not our special case
1009 }
1010
1011 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1012 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1013 if (strcmp(s1, s2) != 0) {
1014 return false; // strings don't match; not our special case
1015 }
1016
1017 return true; // made it through the gauntlet; this is our special case
1018 } // end is_unresolved_class_mismatch()
1019
1020
1021 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1022
1023 // For consistency allocate memory using os::malloc wrapper.
1024 _scratch_classes = (InstanceKlass**)
1025 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1026 if (_scratch_classes == NULL) {
1027 return JVMTI_ERROR_OUT_OF_MEMORY;
1028 }
1029 // Zero initialize the _scratch_classes array.
1030 for (int i = 0; i < _class_count; i++) {
1031 _scratch_classes[i] = NULL;
1032 }
1033
1034 ResourceMark rm(THREAD);
1035
1036 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1037 // state can only be NULL if the current thread is exiting which
1038 // should not happen since we're trying to do a RedefineClasses
1039 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1040 for (int i = 0; i < _class_count; i++) {
1041 // Create HandleMark so that any handles created while loading new class
1042 // versions are deleted. Constant pools are deallocated while merging
1043 // constant pools
1044 HandleMark hm(THREAD);
1045 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1046 Symbol* the_class_sym = the_class->name();
1047
1048 log_debug(redefine, class, load)
1049 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1050 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1051
1052 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1053 _class_defs[i].class_byte_count,
1054 "__VM_RedefineClasses__",
1055 ClassFileStream::verify);
1056
1057 // Parse the stream.
1058 Handle the_class_loader(THREAD, the_class->class_loader());
1059 Handle protection_domain(THREAD, the_class->protection_domain());
1060 // Set redefined class handle in JvmtiThreadState class.
1061 // This redefined class is sent to agent event handler for class file
1062 // load hook event.
1063 state->set_class_being_redefined(the_class, _class_load_kind);
1064
1065 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1066 the_class_sym,
1067 the_class_loader,
1068 protection_domain,
1069 &st,
1070 THREAD);
1071 // Clear class_being_redefined just to be sure.
1072 state->clear_class_being_redefined();
1073
1074 // TODO: if this is retransform, and nothing changed we can skip it
1075
1076 // Need to clean up allocated InstanceKlass if there's an error so assign
1077 // the result here. Caller deallocates all the scratch classes in case of
1078 // an error.
1079 _scratch_classes[i] = scratch_class;
1080
1081 if (HAS_PENDING_EXCEPTION) {
1082 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1083 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1084 CLEAR_PENDING_EXCEPTION;
1085
1086 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1087 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1088 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1089 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1090 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1091 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1092 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1093 // The message will be "XXX (wrong name: YYY)"
1094 return JVMTI_ERROR_NAMES_DONT_MATCH;
1095 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1096 return JVMTI_ERROR_OUT_OF_MEMORY;
1097 } else { // Just in case more exceptions can be thrown..
1098 return JVMTI_ERROR_FAILS_VERIFICATION;
1099 }
1100 }
1101
1102 // Ensure class is linked before redefine
1103 if (!the_class->is_linked()) {
1104 the_class->link_class(THREAD);
1105 if (HAS_PENDING_EXCEPTION) {
1106 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1107 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1108 CLEAR_PENDING_EXCEPTION;
1109 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1110 return JVMTI_ERROR_OUT_OF_MEMORY;
1111 } else {
1112 return JVMTI_ERROR_INTERNAL;
1113 }
1114 }
1115 }
1116
1117 // Do the validity checks in compare_and_normalize_class_versions()
1118 // before verifying the byte codes. By doing these checks first, we
1119 // limit the number of functions that require redirection from
1120 // the_class to scratch_class. In particular, we don't have to
1121 // modify JNI GetSuperclass() and thus won't change its performance.
1122 jvmtiError res = compare_and_normalize_class_versions(the_class,
1123 scratch_class);
1124 if (res != JVMTI_ERROR_NONE) {
1125 return res;
1126 }
1127
1128 // verify what the caller passed us
1129 {
1130 // The bug 6214132 caused the verification to fail.
1131 // Information about the_class and scratch_class is temporarily
1132 // recorded into jvmtiThreadState. This data is used to redirect
1133 // the_class to scratch_class in the JVM_* functions called by the
1134 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1135 // description.
1136 RedefineVerifyMark rvm(the_class, scratch_class, state);
1137 Verifier::verify(
1138 scratch_class, Verifier::ThrowException, true, THREAD);
1139 }
1140
1141 if (HAS_PENDING_EXCEPTION) {
1142 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1143 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1144 CLEAR_PENDING_EXCEPTION;
1145 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1146 return JVMTI_ERROR_OUT_OF_MEMORY;
1147 } else {
1148 // tell the caller the bytecodes are bad
1149 return JVMTI_ERROR_FAILS_VERIFICATION;
1150 }
1151 }
1152
1153 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1154 if (HAS_PENDING_EXCEPTION) {
1155 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1156 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1157 CLEAR_PENDING_EXCEPTION;
1158 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1159 return JVMTI_ERROR_OUT_OF_MEMORY;
1160 } else {
1161 return JVMTI_ERROR_INTERNAL;
1162 }
1163 }
1164
1165 if (VerifyMergedCPBytecodes) {
1166 // verify what we have done during constant pool merging
1167 {
1168 RedefineVerifyMark rvm(the_class, scratch_class, state);
1169 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1170 }
1171
1172 if (HAS_PENDING_EXCEPTION) {
1173 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1174 log_info(redefine, class, load, exceptions)
1175 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1176 CLEAR_PENDING_EXCEPTION;
1177 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1178 return JVMTI_ERROR_OUT_OF_MEMORY;
1179 } else {
1180 // tell the caller that constant pool merging screwed up
1181 return JVMTI_ERROR_INTERNAL;
1182 }
1183 }
1184 }
1185
1186 Rewriter::rewrite(scratch_class, THREAD);
1187 if (!HAS_PENDING_EXCEPTION) {
1188 scratch_class->link_methods(THREAD);
1189 }
1190 if (HAS_PENDING_EXCEPTION) {
1191 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1192 log_info(redefine, class, load, exceptions)
1193 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1194 CLEAR_PENDING_EXCEPTION;
1195 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1196 return JVMTI_ERROR_OUT_OF_MEMORY;
1197 } else {
1198 return JVMTI_ERROR_INTERNAL;
1199 }
1200 }
1201
1202 log_debug(redefine, class, load)
1203 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1204 }
1205
1206 return JVMTI_ERROR_NONE;
1207 }
1208
1209
1210 // Map old_index to new_index as needed. scratch_cp is only needed
1211 // for log calls.
1212 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1213 int old_index, int new_index) {
1214 if (find_new_index(old_index) != 0) {
1215 // old_index is already mapped
1216 return;
1217 }
1218
1219 if (old_index == new_index) {
1220 // no mapping is needed
1221 return;
1222 }
1223
1224 _index_map_p->at_put(old_index, new_index);
1225 _index_map_count++;
1226
1227 log_trace(redefine, class, constantpool)
1228 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1229 } // end map_index()
1230
1231
1232 // Map old_index to new_index as needed.
1233 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1234 if (find_new_operand_index(old_index) != -1) {
1235 // old_index is already mapped
1236 return;
1237 }
1238
1239 if (old_index == new_index) {
1240 // no mapping is needed
1241 return;
1242 }
1243
1244 _operands_index_map_p->at_put(old_index, new_index);
1245 _operands_index_map_count++;
1246
1247 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1248 } // end map_index()
1249
1250
1251 // Merge old_cp and scratch_cp and return the results of the merge via
1252 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1253 // merge_cp_length_p. The entries in old_cp occupy the same locations
1254 // in *merge_cp_p. Also creates a map of indices from entries in
1255 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1256 // entries are only created for entries in scratch_cp that occupy a
1257 // different location in *merged_cp_p.
1258 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1259 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1260 int *merge_cp_length_p, TRAPS) {
1261
1262 if (merge_cp_p == NULL) {
1263 assert(false, "caller must provide scratch constantPool");
1264 return false; // robustness
1265 }
1266 if (merge_cp_length_p == NULL) {
1267 assert(false, "caller must provide scratch CP length");
1268 return false; // robustness
1269 }
1270 // Worst case we need old_cp->length() + scratch_cp()->length(),
1271 // but the caller might be smart so make sure we have at least
1272 // the minimum.
1273 if ((*merge_cp_p)->length() < old_cp->length()) {
1274 assert(false, "merge area too small");
1275 return false; // robustness
1276 }
1277
1278 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1279
1280 {
1281 // Pass 0:
1282 // The old_cp is copied to *merge_cp_p; this means that any code
1283 // using old_cp does not have to change. This work looks like a
1284 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1285 // handle one special case:
1286 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1287 // This will make verification happy.
1288
1289 int old_i; // index into old_cp
1290
1291 // index zero (0) is not used in constantPools
1292 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1293 // leave debugging crumb
1294 jbyte old_tag = old_cp->tag_at(old_i).value();
1295 switch (old_tag) {
1296 case JVM_CONSTANT_Class:
1297 case JVM_CONSTANT_UnresolvedClass:
1298 // revert the copy to JVM_CONSTANT_UnresolvedClass
1299 // May be resolving while calling this so do the same for
1300 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1301 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1302 old_cp->klass_name_index_at(old_i));
1303 break;
1304
1305 case JVM_CONSTANT_Double:
1306 case JVM_CONSTANT_Long:
1307 // just copy the entry to *merge_cp_p, but double and long take
1308 // two constant pool entries
1309 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1310 old_i++;
1311 break;
1312
1313 default:
1314 // just copy the entry to *merge_cp_p
1315 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1316 break;
1317 }
1318 } // end for each old_cp entry
1319
1320 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1321 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1322
1323 // We don't need to sanity check that *merge_cp_length_p is within
1324 // *merge_cp_p bounds since we have the minimum on-entry check above.
1325 (*merge_cp_length_p) = old_i;
1326 }
1327
1328 // merge_cp_len should be the same as old_cp->length() at this point
1329 // so this trace message is really a "warm-and-breathing" message.
1330 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1331
1332 int scratch_i; // index into scratch_cp
1333 {
1334 // Pass 1a:
1335 // Compare scratch_cp entries to the old_cp entries that we have
1336 // already copied to *merge_cp_p. In this pass, we are eliminating
1337 // exact duplicates (matching entry at same index) so we only
1338 // compare entries in the common indice range.
1339 int increment = 1;
1340 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1341 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1342 switch (scratch_cp->tag_at(scratch_i).value()) {
1343 case JVM_CONSTANT_Double:
1344 case JVM_CONSTANT_Long:
1345 // double and long take two constant pool entries
1346 increment = 2;
1347 break;
1348
1349 default:
1350 increment = 1;
1351 break;
1352 }
1353
1354 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1355 scratch_i, CHECK_0);
1356 if (match) {
1357 // found a match at the same index so nothing more to do
1358 continue;
1359 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1360 *merge_cp_p, scratch_i)) {
1361 // The mismatch in compare_entry_to() above is because of a
1362 // resolved versus unresolved class entry at the same index
1363 // with the same string value. Since Pass 0 reverted any
1364 // class entries to unresolved class entries in *merge_cp_p,
1365 // we go with the unresolved class entry.
1366 continue;
1367 }
1368
1369 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1370 CHECK_0);
1371 if (found_i != 0) {
1372 guarantee(found_i != scratch_i,
1373 "compare_entry_to() and find_matching_entry() do not agree");
1374
1375 // Found a matching entry somewhere else in *merge_cp_p so
1376 // just need a mapping entry.
1377 map_index(scratch_cp, scratch_i, found_i);
1378 continue;
1379 }
1380
1381 // The find_matching_entry() call above could fail to find a match
1382 // due to a resolved versus unresolved class or string entry situation
1383 // like we solved above with the is_unresolved_*_mismatch() calls.
1384 // However, we would have to call is_unresolved_*_mismatch() over
1385 // all of *merge_cp_p (potentially) and that doesn't seem to be
1386 // worth the time.
1387
1388 // No match found so we have to append this entry and any unique
1389 // referenced entries to *merge_cp_p.
1390 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1391 CHECK_0);
1392 }
1393 }
1394
1395 log_debug(redefine, class, constantpool)
1396 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1397 *merge_cp_length_p, scratch_i, _index_map_count);
1398
1399 if (scratch_i < scratch_cp->length()) {
1400 // Pass 1b:
1401 // old_cp is smaller than scratch_cp so there are entries in
1402 // scratch_cp that we have not yet processed. We take care of
1403 // those now.
1404 int increment = 1;
1405 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1406 switch (scratch_cp->tag_at(scratch_i).value()) {
1407 case JVM_CONSTANT_Double:
1408 case JVM_CONSTANT_Long:
1409 // double and long take two constant pool entries
1410 increment = 2;
1411 break;
1412
1413 default:
1414 increment = 1;
1415 break;
1416 }
1417
1418 int found_i =
1419 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1420 if (found_i != 0) {
1421 // Found a matching entry somewhere else in *merge_cp_p so
1422 // just need a mapping entry.
1423 map_index(scratch_cp, scratch_i, found_i);
1424 continue;
1425 }
1426
1427 // No match found so we have to append this entry and any unique
1428 // referenced entries to *merge_cp_p.
1429 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1430 CHECK_0);
1431 }
1432
1433 log_debug(redefine, class, constantpool)
1434 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1435 *merge_cp_length_p, scratch_i, _index_map_count);
1436 }
1437 finalize_operands_merge(*merge_cp_p, THREAD);
1438
1439 return true;
1440 } // end merge_constant_pools()
1441
1442
1443 // Scoped object to clean up the constant pool(s) created for merging
1444 class MergeCPCleaner {
1445 ClassLoaderData* _loader_data;
1446 ConstantPool* _cp;
1447 ConstantPool* _scratch_cp;
1448 public:
1449 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1450 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1451 ~MergeCPCleaner() {
1452 _loader_data->add_to_deallocate_list(_cp);
1453 if (_scratch_cp != NULL) {
1454 _loader_data->add_to_deallocate_list(_scratch_cp);
1455 }
1456 }
1457 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1458 };
1459
1460 // Merge constant pools between the_class and scratch_class and
1461 // potentially rewrite bytecodes in scratch_class to use the merged
1462 // constant pool.
1463 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1464 InstanceKlass* the_class, InstanceKlass* scratch_class,
1465 TRAPS) {
1466 // worst case merged constant pool length is old and new combined
1467 int merge_cp_length = the_class->constants()->length()
1468 + scratch_class->constants()->length();
1469
1470 // Constant pools are not easily reused so we allocate a new one
1471 // each time.
1472 // merge_cp is created unsafe for concurrent GC processing. It
1473 // should be marked safe before discarding it. Even though
1474 // garbage, if it crosses a card boundary, it may be scanned
1475 // in order to find the start of the first complete object on the card.
1476 ClassLoaderData* loader_data = the_class->class_loader_data();
1477 ConstantPool* merge_cp_oop =
1478 ConstantPool::allocate(loader_data,
1479 merge_cp_length,
1480 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1481 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1482
1483 HandleMark hm(THREAD); // make sure handles are cleared before
1484 // MergeCPCleaner clears out merge_cp_oop
1485 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1486
1487 // Get constants() from the old class because it could have been rewritten
1488 // while we were at a safepoint allocating a new constant pool.
1489 constantPoolHandle old_cp(THREAD, the_class->constants());
1490 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1491
1492 // If the length changed, the class was redefined out from under us. Return
1493 // an error.
1494 if (merge_cp_length != the_class->constants()->length()
1495 + scratch_class->constants()->length()) {
1496 return JVMTI_ERROR_INTERNAL;
1497 }
1498
1499 // Update the version number of the constant pools (may keep scratch_cp)
1500 merge_cp->increment_and_save_version(old_cp->version());
1501 scratch_cp->increment_and_save_version(old_cp->version());
1502
1503 ResourceMark rm(THREAD);
1504 _index_map_count = 0;
1505 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1506
1507 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1508 _operands_index_map_count = 0;
1509 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1510 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1511
1512 // reference to the cp holder is needed for copy_operands()
1513 merge_cp->set_pool_holder(scratch_class);
1514 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1515 &merge_cp_length, THREAD);
1516 merge_cp->set_pool_holder(NULL);
1517
1518 if (!result) {
1519 // The merge can fail due to memory allocation failure or due
1520 // to robustness checks.
1521 return JVMTI_ERROR_INTERNAL;
1522 }
1523
1524 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1525
1526 if (_index_map_count == 0) {
1527 // there is nothing to map between the new and merged constant pools
1528
1529 if (old_cp->length() == scratch_cp->length()) {
1530 // The old and new constant pools are the same length and the
1531 // index map is empty. This means that the three constant pools
1532 // are equivalent (but not the same). Unfortunately, the new
1533 // constant pool has not gone through link resolution nor have
1534 // the new class bytecodes gone through constant pool cache
1535 // rewriting so we can't use the old constant pool with the new
1536 // class.
1537
1538 // toss the merged constant pool at return
1539 } else if (old_cp->length() < scratch_cp->length()) {
1540 // The old constant pool has fewer entries than the new constant
1541 // pool and the index map is empty. This means the new constant
1542 // pool is a superset of the old constant pool. However, the old
1543 // class bytecodes have already gone through constant pool cache
1544 // rewriting so we can't use the new constant pool with the old
1545 // class.
1546
1547 // toss the merged constant pool at return
1548 } else {
1549 // The old constant pool has more entries than the new constant
1550 // pool and the index map is empty. This means that both the old
1551 // and merged constant pools are supersets of the new constant
1552 // pool.
1553
1554 // Replace the new constant pool with a shrunken copy of the
1555 // merged constant pool
1556 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1557 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1558 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1559 // It can't be cleaned up while there are handles to it.
1560 cp_cleaner.add_scratch_cp(scratch_cp());
1561 }
1562 } else {
1563 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1564 // don't want to loop unless we are tracing
1565 int count = 0;
1566 for (int i = 1; i < _index_map_p->length(); i++) {
1567 int value = _index_map_p->at(i);
1568
1569 if (value != -1) {
1570 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1571 count++;
1572 }
1573 }
1574 }
1575
1576 // We have entries mapped between the new and merged constant pools
1577 // so we have to rewrite some constant pool references.
1578 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1579 return JVMTI_ERROR_INTERNAL;
1580 }
1581
1582 // Replace the new constant pool with a shrunken copy of the
1583 // merged constant pool so now the rewritten bytecodes have
1584 // valid references; the previous new constant pool will get
1585 // GCed.
1586 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1587 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1588 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1589 // It can't be cleaned up while there are handles to it.
1590 cp_cleaner.add_scratch_cp(scratch_cp());
1591 }
1592
1593 return JVMTI_ERROR_NONE;
1594 } // end merge_cp_and_rewrite()
1595
1596
1597 // Rewrite constant pool references in klass scratch_class.
1598 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1599 TRAPS) {
1600
1601 // rewrite constant pool references in the methods:
1602 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1603 // propagate failure back to caller
1604 return false;
1605 }
1606
1607 // rewrite constant pool references in the class_annotations:
1608 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1609 // propagate failure back to caller
1610 return false;
1611 }
1612
1613 // rewrite constant pool references in the fields_annotations:
1614 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1615 // propagate failure back to caller
1616 return false;
1617 }
1618
1619 // rewrite constant pool references in the methods_annotations:
1620 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1621 // propagate failure back to caller
1622 return false;
1623 }
1624
1625 // rewrite constant pool references in the methods_parameter_annotations:
1626 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1627 THREAD)) {
1628 // propagate failure back to caller
1629 return false;
1630 }
1631
1632 // rewrite constant pool references in the methods_default_annotations:
1633 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1634 THREAD)) {
1635 // propagate failure back to caller
1636 return false;
1637 }
1638
1639 // rewrite constant pool references in the class_type_annotations:
1640 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1641 // propagate failure back to caller
1642 return false;
1643 }
1644
1645 // rewrite constant pool references in the fields_type_annotations:
1646 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1647 // propagate failure back to caller
1648 return false;
1649 }
1650
1651 // rewrite constant pool references in the methods_type_annotations:
1652 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1653 // propagate failure back to caller
1654 return false;
1655 }
1656
1657 // There can be type annotations in the Code part of a method_info attribute.
1658 // These annotations are not accessible, even by reflection.
1659 // Currently they are not even parsed by the ClassFileParser.
1660 // If runtime access is added they will also need to be rewritten.
1661
1662 // rewrite source file name index:
1663 u2 source_file_name_idx = scratch_class->source_file_name_index();
1664 if (source_file_name_idx != 0) {
1665 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1666 if (new_source_file_name_idx != 0) {
1667 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1668 }
1669 }
1670
1671 // rewrite class generic signature index:
1672 u2 generic_signature_index = scratch_class->generic_signature_index();
1673 if (generic_signature_index != 0) {
1674 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1675 if (new_generic_signature_index != 0) {
1676 scratch_class->set_generic_signature_index(new_generic_signature_index);
1677 }
1678 }
1679
1680 return true;
1681 } // end rewrite_cp_refs()
1682
1683 // Rewrite constant pool references in the methods.
1684 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1685 InstanceKlass* scratch_class, TRAPS) {
1686
1687 Array<Method*>* methods = scratch_class->methods();
1688
1689 if (methods == NULL || methods->length() == 0) {
1690 // no methods so nothing to do
1691 return true;
1692 }
1693
1694 // rewrite constant pool references in the methods:
1695 for (int i = methods->length() - 1; i >= 0; i--) {
1696 methodHandle method(THREAD, methods->at(i));
1697 methodHandle new_method;
1698 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1699 if (!new_method.is_null()) {
1700 // the method has been replaced so save the new method version
1701 // even in the case of an exception. original method is on the
1702 // deallocation list.
1703 methods->at_put(i, new_method());
1704 }
1705 if (HAS_PENDING_EXCEPTION) {
1706 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1707 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1708 // Need to clear pending exception here as the super caller sets
1709 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1710 CLEAR_PENDING_EXCEPTION;
1711 return false;
1712 }
1713 }
1714
1715 return true;
1716 }
1717
1718
1719 // Rewrite constant pool references in the specific method. This code
1720 // was adapted from Rewriter::rewrite_method().
1721 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1722 methodHandle *new_method_p, TRAPS) {
1723
1724 *new_method_p = methodHandle(); // default is no new method
1725
1726 // We cache a pointer to the bytecodes here in code_base. If GC
1727 // moves the Method*, then the bytecodes will also move which
1728 // will likely cause a crash. We create a NoSafepointVerifier
1729 // object to detect whether we pass a possible safepoint in this
1730 // code block.
1731 NoSafepointVerifier nsv;
1732
1733 // Bytecodes and their length
1734 address code_base = method->code_base();
1735 int code_length = method->code_size();
1736
1737 int bc_length;
1738 for (int bci = 0; bci < code_length; bci += bc_length) {
1739 address bcp = code_base + bci;
1740 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1741
1742 bc_length = Bytecodes::length_for(c);
1743 if (bc_length == 0) {
1744 // More complicated bytecodes report a length of zero so
1745 // we have to try again a slightly different way.
1746 bc_length = Bytecodes::length_at(method(), bcp);
1747 }
1748
1749 assert(bc_length != 0, "impossible bytecode length");
1750
1751 switch (c) {
1752 case Bytecodes::_ldc:
1753 {
1754 int cp_index = *(bcp + 1);
1755 int new_index = find_new_index(cp_index);
1756
1757 if (StressLdcRewrite && new_index == 0) {
1758 // If we are stressing ldc -> ldc_w rewriting, then we
1759 // always need a new_index value.
1760 new_index = cp_index;
1761 }
1762 if (new_index != 0) {
1763 // the original index is mapped so we have more work to do
1764 if (!StressLdcRewrite && new_index <= max_jubyte) {
1765 // The new value can still use ldc instead of ldc_w
1766 // unless we are trying to stress ldc -> ldc_w rewriting
1767 log_trace(redefine, class, constantpool)
1768 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1769 *(bcp + 1) = new_index;
1770 } else {
1771 log_trace(redefine, class, constantpool)
1772 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
1773 // the new value needs ldc_w instead of ldc
1774 u_char inst_buffer[4]; // max instruction size is 4 bytes
1775 bcp = (address)inst_buffer;
1776 // construct new instruction sequence
1777 *bcp = Bytecodes::_ldc_w;
1778 bcp++;
1779 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1780 // See comment below for difference between put_Java_u2()
1781 // and put_native_u2().
1782 Bytes::put_Java_u2(bcp, new_index);
1783
1784 Relocator rc(method, NULL /* no RelocatorListener needed */);
1785 methodHandle m;
1786 {
1787 PauseNoSafepointVerifier pnsv(&nsv);
1788
1789 // ldc is 2 bytes and ldc_w is 3 bytes
1790 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1791 }
1792
1793 // return the new method so that the caller can update
1794 // the containing class
1795 *new_method_p = method = m;
1796 // switch our bytecode processing loop from the old method
1797 // to the new method
1798 code_base = method->code_base();
1799 code_length = method->code_size();
1800 bcp = code_base + bci;
1801 c = (Bytecodes::Code)(*bcp);
1802 bc_length = Bytecodes::length_for(c);
1803 assert(bc_length != 0, "sanity check");
1804 } // end we need ldc_w instead of ldc
1805 } // end if there is a mapped index
1806 } break;
1807
1808 // these bytecodes have a two-byte constant pool index
1809 case Bytecodes::_anewarray : // fall through
1810 case Bytecodes::_checkcast : // fall through
1811 case Bytecodes::_getfield : // fall through
1812 case Bytecodes::_getstatic : // fall through
1813 case Bytecodes::_instanceof : // fall through
1814 case Bytecodes::_invokedynamic : // fall through
1815 case Bytecodes::_invokeinterface: // fall through
1816 case Bytecodes::_invokespecial : // fall through
1817 case Bytecodes::_invokestatic : // fall through
1818 case Bytecodes::_invokevirtual : // fall through
1819 case Bytecodes::_ldc_w : // fall through
1820 case Bytecodes::_ldc2_w : // fall through
1821 case Bytecodes::_multianewarray : // fall through
1822 case Bytecodes::_new : // fall through
1823 case Bytecodes::_putfield : // fall through
1824 case Bytecodes::_putstatic :
1825 {
1826 address p = bcp + 1;
1827 int cp_index = Bytes::get_Java_u2(p);
1828 int new_index = find_new_index(cp_index);
1829 if (new_index != 0) {
1830 // the original index is mapped so update w/ new value
1831 log_trace(redefine, class, constantpool)
1832 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
1833 // Rewriter::rewrite_method() uses put_native_u2() in this
1834 // situation because it is reusing the constant pool index
1835 // location for a native index into the ConstantPoolCache.
1836 // Since we are updating the constant pool index prior to
1837 // verification and ConstantPoolCache initialization, we
1838 // need to keep the new index in Java byte order.
1839 Bytes::put_Java_u2(p, new_index);
1840 }
1841 } break;
1842 default:
1843 break;
1844 }
1845 } // end for each bytecode
1846
1847 // We also need to rewrite the parameter name indexes, if there is
1848 // method parameter data present
1849 if(method->has_method_parameters()) {
1850 const int len = method->method_parameters_length();
1851 MethodParametersElement* elem = method->method_parameters_start();
1852
1853 for (int i = 0; i < len; i++) {
1854 const u2 cp_index = elem[i].name_cp_index;
1855 const u2 new_cp_index = find_new_index(cp_index);
1856 if (new_cp_index != 0) {
1857 elem[i].name_cp_index = new_cp_index;
1858 }
1859 }
1860 }
1861 } // end rewrite_cp_refs_in_method()
1862
1863
1864 // Rewrite constant pool references in the class_annotations field.
1865 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1866 InstanceKlass* scratch_class, TRAPS) {
1867
1868 AnnotationArray* class_annotations = scratch_class->class_annotations();
1869 if (class_annotations == NULL || class_annotations->length() == 0) {
1870 // no class_annotations so nothing to do
1871 return true;
1872 }
1873
1874 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
1875
1876 int byte_i = 0; // byte index into class_annotations
1877 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1878 THREAD);
1879 }
1880
1881
1882 // Rewrite constant pool references in an annotations typeArray. This
1883 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1884 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1885 //
1886 // annotations_typeArray {
1887 // u2 num_annotations;
1888 // annotation annotations[num_annotations];
1889 // }
1890 //
1891 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1892 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1893
1894 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1895 // not enough room for num_annotations field
1896 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
1897 return false;
1898 }
1899
1900 u2 num_annotations = Bytes::get_Java_u2((address)
1901 annotations_typeArray->adr_at(byte_i_ref));
1902 byte_i_ref += 2;
1903
1904 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
1905
1906 int calc_num_annotations = 0;
1907 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1908 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1909 byte_i_ref, THREAD)) {
1910 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
1911 // propagate failure back to caller
1912 return false;
1913 }
1914 }
1915 assert(num_annotations == calc_num_annotations, "sanity check");
1916
1917 return true;
1918 } // end rewrite_cp_refs_in_annotations_typeArray()
1919
1920
1921 // Rewrite constant pool references in the annotation struct portion of
1922 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1923 // the 2nd-edition of the VM spec:
1924 //
1925 // struct annotation {
1926 // u2 type_index;
1927 // u2 num_element_value_pairs;
1928 // {
1929 // u2 element_name_index;
1930 // element_value value;
1931 // } element_value_pairs[num_element_value_pairs];
1932 // }
1933 //
1934 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1935 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1936 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1937 // not enough room for smallest annotation_struct
1938 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
1939 return false;
1940 }
1941
1942 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1943 byte_i_ref, "type_index", THREAD);
1944
1945 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1946 annotations_typeArray->adr_at(byte_i_ref));
1947 byte_i_ref += 2;
1948
1949 log_debug(redefine, class, annotation)
1950 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
1951
1952 int calc_num_element_value_pairs = 0;
1953 for (; calc_num_element_value_pairs < num_element_value_pairs;
1954 calc_num_element_value_pairs++) {
1955 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1956 // not enough room for another element_name_index, let alone
1957 // the rest of another component
1958 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
1959 return false;
1960 }
1961
1962 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1963 annotations_typeArray, byte_i_ref,
1964 "element_name_index", THREAD);
1965
1966 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
1967
1968 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1969 byte_i_ref, THREAD)) {
1970 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
1971 // propagate failure back to caller
1972 return false;
1973 }
1974 } // end for each component
1975 assert(num_element_value_pairs == calc_num_element_value_pairs,
1976 "sanity check");
1977
1978 return true;
1979 } // end rewrite_cp_refs_in_annotation_struct()
1980
1981
1982 // Rewrite a constant pool reference at the current position in
1983 // annotations_typeArray if needed. Returns the original constant
1984 // pool reference if a rewrite was not needed or the new constant
1985 // pool reference if a rewrite was needed.
1986 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1987 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1988 const char * trace_mesg, TRAPS) {
1989
1990 address cp_index_addr = (address)
1991 annotations_typeArray->adr_at(byte_i_ref);
1992 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1993 u2 new_cp_index = find_new_index(old_cp_index);
1994 if (new_cp_index != 0) {
1995 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
1996 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1997 old_cp_index = new_cp_index;
1998 }
1999 byte_i_ref += 2;
2000 return old_cp_index;
2001 }
2002
2003
2004 // Rewrite constant pool references in the element_value portion of an
2005 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2006 // the 2nd-edition of the VM spec:
2007 //
2008 // struct element_value {
2009 // u1 tag;
2010 // union {
2011 // u2 const_value_index;
2012 // {
2013 // u2 type_name_index;
2014 // u2 const_name_index;
2015 // } enum_const_value;
2016 // u2 class_info_index;
2017 // annotation annotation_value;
2018 // struct {
2019 // u2 num_values;
2020 // element_value values[num_values];
2021 // } array_value;
2022 // } value;
2023 // }
2024 //
2025 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2026 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2027
2028 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2029 // not enough room for a tag let alone the rest of an element_value
2030 log_debug(redefine, class, annotation)("length() is too small for a tag");
2031 return false;
2032 }
2033
2034 u1 tag = annotations_typeArray->at(byte_i_ref);
2035 byte_i_ref++;
2036 log_debug(redefine, class, annotation)("tag='%c'", tag);
2037
2038 switch (tag) {
2039 // These BaseType tag values are from Table 4.2 in VM spec:
2040 case 'B': // byte
2041 case 'C': // char
2042 case 'D': // double
2043 case 'F': // float
2044 case 'I': // int
2045 case 'J': // long
2046 case 'S': // short
2047 case 'Z': // boolean
2048
2049 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2050 // the VM spec:
2051 case 's':
2052 {
2053 // For the above tag values (including the BaseType values),
2054 // value.const_value_index is right union field.
2055
2056 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2057 // not enough room for a const_value_index
2058 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2059 return false;
2060 }
2061
2062 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2063 annotations_typeArray, byte_i_ref,
2064 "const_value_index", THREAD);
2065
2066 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2067 } break;
2068
2069 case 'e':
2070 {
2071 // for the above tag value, value.enum_const_value is right union field
2072
2073 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2074 // not enough room for a enum_const_value
2075 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2076 return false;
2077 }
2078
2079 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2080 annotations_typeArray, byte_i_ref,
2081 "type_name_index", THREAD);
2082
2083 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2084 annotations_typeArray, byte_i_ref,
2085 "const_name_index", THREAD);
2086
2087 log_debug(redefine, class, annotation)
2088 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2089 } break;
2090
2091 case 'c':
2092 {
2093 // for the above tag value, value.class_info_index is right union field
2094
2095 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2096 // not enough room for a class_info_index
2097 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2098 return false;
2099 }
2100
2101 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2102 annotations_typeArray, byte_i_ref,
2103 "class_info_index", THREAD);
2104
2105 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2106 } break;
2107
2108 case '@':
2109 // For the above tag value, value.attr_value is the right union
2110 // field. This is a nested annotation.
2111 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2112 byte_i_ref, THREAD)) {
2113 // propagate failure back to caller
2114 return false;
2115 }
2116 break;
2117
2118 case '[':
2119 {
2120 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2121 // not enough room for a num_values field
2122 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2123 return false;
2124 }
2125
2126 // For the above tag value, value.array_value is the right union
2127 // field. This is an array of nested element_value.
2128 u2 num_values = Bytes::get_Java_u2((address)
2129 annotations_typeArray->adr_at(byte_i_ref));
2130 byte_i_ref += 2;
2131 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2132
2133 int calc_num_values = 0;
2134 for (; calc_num_values < num_values; calc_num_values++) {
2135 if (!rewrite_cp_refs_in_element_value(
2136 annotations_typeArray, byte_i_ref, THREAD)) {
2137 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2138 // propagate failure back to caller
2139 return false;
2140 }
2141 }
2142 assert(num_values == calc_num_values, "sanity check");
2143 } break;
2144
2145 default:
2146 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2147 return false;
2148 } // end decode tag field
2149
2150 return true;
2151 } // end rewrite_cp_refs_in_element_value()
2152
2153
2154 // Rewrite constant pool references in a fields_annotations field.
2155 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2156 InstanceKlass* scratch_class, TRAPS) {
2157
2158 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2159
2160 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2161 // no fields_annotations so nothing to do
2162 return true;
2163 }
2164
2165 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2166
2167 for (int i = 0; i < fields_annotations->length(); i++) {
2168 AnnotationArray* field_annotations = fields_annotations->at(i);
2169 if (field_annotations == NULL || field_annotations->length() == 0) {
2170 // this field does not have any annotations so skip it
2171 continue;
2172 }
2173
2174 int byte_i = 0; // byte index into field_annotations
2175 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2176 THREAD)) {
2177 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2178 // propagate failure back to caller
2179 return false;
2180 }
2181 }
2182
2183 return true;
2184 } // end rewrite_cp_refs_in_fields_annotations()
2185
2186
2187 // Rewrite constant pool references in a methods_annotations field.
2188 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2189 InstanceKlass* scratch_class, TRAPS) {
2190
2191 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2192 Method* m = scratch_class->methods()->at(i);
2193 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2194
2195 if (method_annotations == NULL || method_annotations->length() == 0) {
2196 // this method does not have any annotations so skip it
2197 continue;
2198 }
2199
2200 int byte_i = 0; // byte index into method_annotations
2201 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2202 THREAD)) {
2203 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2204 // propagate failure back to caller
2205 return false;
2206 }
2207 }
2208
2209 return true;
2210 } // end rewrite_cp_refs_in_methods_annotations()
2211
2212
2213 // Rewrite constant pool references in a methods_parameter_annotations
2214 // field. This "structure" is adapted from the
2215 // RuntimeVisibleParameterAnnotations_attribute described in section
2216 // 4.8.17 of the 2nd-edition of the VM spec:
2217 //
2218 // methods_parameter_annotations_typeArray {
2219 // u1 num_parameters;
2220 // {
2221 // u2 num_annotations;
2222 // annotation annotations[num_annotations];
2223 // } parameter_annotations[num_parameters];
2224 // }
2225 //
2226 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2227 InstanceKlass* scratch_class, TRAPS) {
2228
2229 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2230 Method* m = scratch_class->methods()->at(i);
2231 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2232 if (method_parameter_annotations == NULL
2233 || method_parameter_annotations->length() == 0) {
2234 // this method does not have any parameter annotations so skip it
2235 continue;
2236 }
2237
2238 if (method_parameter_annotations->length() < 1) {
2239 // not enough room for a num_parameters field
2240 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2241 return false;
2242 }
2243
2244 int byte_i = 0; // byte index into method_parameter_annotations
2245
2246 u1 num_parameters = method_parameter_annotations->at(byte_i);
2247 byte_i++;
2248
2249 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2250
2251 int calc_num_parameters = 0;
2252 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2253 if (!rewrite_cp_refs_in_annotations_typeArray(
2254 method_parameter_annotations, byte_i, THREAD)) {
2255 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2256 // propagate failure back to caller
2257 return false;
2258 }
2259 }
2260 assert(num_parameters == calc_num_parameters, "sanity check");
2261 }
2262
2263 return true;
2264 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2265
2266
2267 // Rewrite constant pool references in a methods_default_annotations
2268 // field. This "structure" is adapted from the AnnotationDefault_attribute
2269 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2270 //
2271 // methods_default_annotations_typeArray {
2272 // element_value default_value;
2273 // }
2274 //
2275 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2276 InstanceKlass* scratch_class, TRAPS) {
2277
2278 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2279 Method* m = scratch_class->methods()->at(i);
2280 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2281 if (method_default_annotations == NULL
2282 || method_default_annotations->length() == 0) {
2283 // this method does not have any default annotations so skip it
2284 continue;
2285 }
2286
2287 int byte_i = 0; // byte index into method_default_annotations
2288
2289 if (!rewrite_cp_refs_in_element_value(
2290 method_default_annotations, byte_i, THREAD)) {
2291 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2292 // propagate failure back to caller
2293 return false;
2294 }
2295 }
2296
2297 return true;
2298 } // end rewrite_cp_refs_in_methods_default_annotations()
2299
2300
2301 // Rewrite constant pool references in a class_type_annotations field.
2302 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2303 InstanceKlass* scratch_class, TRAPS) {
2304
2305 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2306 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2307 // no class_type_annotations so nothing to do
2308 return true;
2309 }
2310
2311 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2312
2313 int byte_i = 0; // byte index into class_type_annotations
2314 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2315 byte_i, "ClassFile", THREAD);
2316 } // end rewrite_cp_refs_in_class_type_annotations()
2317
2318
2319 // Rewrite constant pool references in a fields_type_annotations field.
2320 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2321 InstanceKlass* scratch_class, TRAPS) {
2322
2323 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2324 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2325 // no fields_type_annotations so nothing to do
2326 return true;
2327 }
2328
2329 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2330
2331 for (int i = 0; i < fields_type_annotations->length(); i++) {
2332 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2333 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2334 // this field does not have any annotations so skip it
2335 continue;
2336 }
2337
2338 int byte_i = 0; // byte index into field_type_annotations
2339 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2340 byte_i, "field_info", THREAD)) {
2341 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2342 // propagate failure back to caller
2343 return false;
2344 }
2345 }
2346
2347 return true;
2348 } // end rewrite_cp_refs_in_fields_type_annotations()
2349
2350
2351 // Rewrite constant pool references in a methods_type_annotations field.
2352 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2353 InstanceKlass* scratch_class, TRAPS) {
2354
2355 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2356 Method* m = scratch_class->methods()->at(i);
2357 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2358
2359 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2360 // this method does not have any annotations so skip it
2361 continue;
2362 }
2363
2364 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2365
2366 int byte_i = 0; // byte index into method_type_annotations
2367 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2368 byte_i, "method_info", THREAD)) {
2369 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2370 // propagate failure back to caller
2371 return false;
2372 }
2373 }
2374
2375 return true;
2376 } // end rewrite_cp_refs_in_methods_type_annotations()
2377
2378
2379 // Rewrite constant pool references in a type_annotations
2380 // field. This "structure" is adapted from the
2381 // RuntimeVisibleTypeAnnotations_attribute described in
2382 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2383 //
2384 // type_annotations_typeArray {
2385 // u2 num_annotations;
2386 // type_annotation annotations[num_annotations];
2387 // }
2388 //
2389 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2390 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2391 const char * location_mesg, TRAPS) {
2392
2393 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2394 // not enough room for num_annotations field
2395 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2396 return false;
2397 }
2398
2399 u2 num_annotations = Bytes::get_Java_u2((address)
2400 type_annotations_typeArray->adr_at(byte_i_ref));
2401 byte_i_ref += 2;
2402
2403 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2404
2405 int calc_num_annotations = 0;
2406 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2407 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2408 byte_i_ref, location_mesg, THREAD)) {
2409 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2410 // propagate failure back to caller
2411 return false;
2412 }
2413 }
2414 assert(num_annotations == calc_num_annotations, "sanity check");
2415
2416 if (byte_i_ref != type_annotations_typeArray->length()) {
2417 log_debug(redefine, class, annotation)
2418 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2419 byte_i_ref, type_annotations_typeArray->length());
2420 return false;
2421 }
2422
2423 return true;
2424 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2425
2426
2427 // Rewrite constant pool references in a type_annotation
2428 // field. This "structure" is adapted from the
2429 // RuntimeVisibleTypeAnnotations_attribute described in
2430 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2431 //
2432 // type_annotation {
2433 // u1 target_type;
2434 // union {
2435 // type_parameter_target;
2436 // supertype_target;
2437 // type_parameter_bound_target;
2438 // empty_target;
2439 // method_formal_parameter_target;
2440 // throws_target;
2441 // localvar_target;
2442 // catch_target;
2443 // offset_target;
2444 // type_argument_target;
2445 // } target_info;
2446 // type_path target_path;
2447 // annotation anno;
2448 // }
2449 //
2450 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2451 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2452 const char * location_mesg, TRAPS) {
2453
2454 if (!skip_type_annotation_target(type_annotations_typeArray,
2455 byte_i_ref, location_mesg, THREAD)) {
2456 return false;
2457 }
2458
2459 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2460 byte_i_ref, THREAD)) {
2461 return false;
2462 }
2463
2464 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2465 byte_i_ref, THREAD)) {
2466 return false;
2467 }
2468
2469 return true;
2470 } // end rewrite_cp_refs_in_type_annotation_struct()
2471
2472
2473 // Read, verify and skip over the target_type and target_info part
2474 // so that rewriting can continue in the later parts of the struct.
2475 //
2476 // u1 target_type;
2477 // union {
2478 // type_parameter_target;
2479 // supertype_target;
2480 // type_parameter_bound_target;
2481 // empty_target;
2482 // method_formal_parameter_target;
2483 // throws_target;
2484 // localvar_target;
2485 // catch_target;
2486 // offset_target;
2487 // type_argument_target;
2488 // } target_info;
2489 //
2490 bool VM_RedefineClasses::skip_type_annotation_target(
2491 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2492 const char * location_mesg, TRAPS) {
2493
2494 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2495 // not enough room for a target_type let alone the rest of a type_annotation
2496 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2497 return false;
2498 }
2499
2500 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2501 byte_i_ref += 1;
2502 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2503 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2504
2505 // Skip over target_info
2506 switch (target_type) {
2507 case 0x00:
2508 // kind: type parameter declaration of generic class or interface
2509 // location: ClassFile
2510 case 0x01:
2511 // kind: type parameter declaration of generic method or constructor
2512 // location: method_info
2513
2514 {
2515 // struct:
2516 // type_parameter_target {
2517 // u1 type_parameter_index;
2518 // }
2519 //
2520 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2521 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2522 return false;
2523 }
2524
2525 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2526 byte_i_ref += 1;
2527
2528 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2529 } break;
2530
2531 case 0x10:
2532 // kind: type in extends clause of class or interface declaration
2533 // (including the direct superclass of an anonymous class declaration),
2534 // or in implements clause of interface declaration
2535 // location: ClassFile
2536
2537 {
2538 // struct:
2539 // supertype_target {
2540 // u2 supertype_index;
2541 // }
2542 //
2543 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2544 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2545 return false;
2546 }
2547
2548 u2 supertype_index = Bytes::get_Java_u2((address)
2549 type_annotations_typeArray->adr_at(byte_i_ref));
2550 byte_i_ref += 2;
2551
2552 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2553 } break;
2554
2555 case 0x11:
2556 // kind: type in bound of type parameter declaration of generic class or interface
2557 // location: ClassFile
2558 case 0x12:
2559 // kind: type in bound of type parameter declaration of generic method or constructor
2560 // location: method_info
2561
2562 {
2563 // struct:
2564 // type_parameter_bound_target {
2565 // u1 type_parameter_index;
2566 // u1 bound_index;
2567 // }
2568 //
2569 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2570 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2571 return false;
2572 }
2573
2574 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2575 byte_i_ref += 1;
2576 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2577 byte_i_ref += 1;
2578
2579 log_debug(redefine, class, annotation)
2580 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2581 } break;
2582
2583 case 0x13:
2584 // kind: type in field declaration
2585 // location: field_info
2586 case 0x14:
2587 // kind: return type of method, or type of newly constructed object
2588 // location: method_info
2589 case 0x15:
2590 // kind: receiver type of method or constructor
2591 // location: method_info
2592
2593 {
2594 // struct:
2595 // empty_target {
2596 // }
2597 //
2598 log_debug(redefine, class, annotation)("empty_target");
2599 } break;
2600
2601 case 0x16:
2602 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2603 // location: method_info
2604
2605 {
2606 // struct:
2607 // formal_parameter_target {
2608 // u1 formal_parameter_index;
2609 // }
2610 //
2611 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2612 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2613 return false;
2614 }
2615
2616 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2617 byte_i_ref += 1;
2618
2619 log_debug(redefine, class, annotation)
2620 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2621 } break;
2622
2623 case 0x17:
2624 // kind: type in throws clause of method or constructor
2625 // location: method_info
2626
2627 {
2628 // struct:
2629 // throws_target {
2630 // u2 throws_type_index
2631 // }
2632 //
2633 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2634 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2635 return false;
2636 }
2637
2638 u2 throws_type_index = Bytes::get_Java_u2((address)
2639 type_annotations_typeArray->adr_at(byte_i_ref));
2640 byte_i_ref += 2;
2641
2642 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2643 } break;
2644
2645 case 0x40:
2646 // kind: type in local variable declaration
2647 // location: Code
2648 case 0x41:
2649 // kind: type in resource variable declaration
2650 // location: Code
2651
2652 {
2653 // struct:
2654 // localvar_target {
2655 // u2 table_length;
2656 // struct {
2657 // u2 start_pc;
2658 // u2 length;
2659 // u2 index;
2660 // } table[table_length];
2661 // }
2662 //
2663 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2664 // not enough room for a table_length let alone the rest of a localvar_target
2665 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2666 return false;
2667 }
2668
2669 u2 table_length = Bytes::get_Java_u2((address)
2670 type_annotations_typeArray->adr_at(byte_i_ref));
2671 byte_i_ref += 2;
2672
2673 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2674
2675 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2676 int table_size = table_length * table_struct_size;
2677
2678 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2679 // not enough room for a table
2680 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2681 return false;
2682 }
2683
2684 // Skip over table
2685 byte_i_ref += table_size;
2686 } break;
2687
2688 case 0x42:
2689 // kind: type in exception parameter declaration
2690 // location: Code
2691
2692 {
2693 // struct:
2694 // catch_target {
2695 // u2 exception_table_index;
2696 // }
2697 //
2698 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2699 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2700 return false;
2701 }
2702
2703 u2 exception_table_index = Bytes::get_Java_u2((address)
2704 type_annotations_typeArray->adr_at(byte_i_ref));
2705 byte_i_ref += 2;
2706
2707 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2708 } break;
2709
2710 case 0x43:
2711 // kind: type in instanceof expression
2712 // location: Code
2713 case 0x44:
2714 // kind: type in new expression
2715 // location: Code
2716 case 0x45:
2717 // kind: type in method reference expression using ::new
2718 // location: Code
2719 case 0x46:
2720 // kind: type in method reference expression using ::Identifier
2721 // location: Code
2722
2723 {
2724 // struct:
2725 // offset_target {
2726 // u2 offset;
2727 // }
2728 //
2729 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2730 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2731 return false;
2732 }
2733
2734 u2 offset = Bytes::get_Java_u2((address)
2735 type_annotations_typeArray->adr_at(byte_i_ref));
2736 byte_i_ref += 2;
2737
2738 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2739 } break;
2740
2741 case 0x47:
2742 // kind: type in cast expression
2743 // location: Code
2744 case 0x48:
2745 // kind: type argument for generic constructor in new expression or
2746 // explicit constructor invocation statement
2747 // location: Code
2748 case 0x49:
2749 // kind: type argument for generic method in method invocation expression
2750 // location: Code
2751 case 0x4A:
2752 // kind: type argument for generic constructor in method reference expression using ::new
2753 // location: Code
2754 case 0x4B:
2755 // kind: type argument for generic method in method reference expression using ::Identifier
2756 // location: Code
2757
2758 {
2759 // struct:
2760 // type_argument_target {
2761 // u2 offset;
2762 // u1 type_argument_index;
2763 // }
2764 //
2765 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2766 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
2767 return false;
2768 }
2769
2770 u2 offset = Bytes::get_Java_u2((address)
2771 type_annotations_typeArray->adr_at(byte_i_ref));
2772 byte_i_ref += 2;
2773 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2774 byte_i_ref += 1;
2775
2776 log_debug(redefine, class, annotation)
2777 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
2778 } break;
2779
2780 default:
2781 log_debug(redefine, class, annotation)("unknown target_type");
2782 #ifdef ASSERT
2783 ShouldNotReachHere();
2784 #endif
2785 return false;
2786 }
2787
2788 return true;
2789 } // end skip_type_annotation_target()
2790
2791
2792 // Read, verify and skip over the type_path part so that rewriting
2793 // can continue in the later parts of the struct.
2794 //
2795 // type_path {
2796 // u1 path_length;
2797 // {
2798 // u1 type_path_kind;
2799 // u1 type_argument_index;
2800 // } path[path_length];
2801 // }
2802 //
2803 bool VM_RedefineClasses::skip_type_annotation_type_path(
2804 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2805
2806 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2807 // not enough room for a path_length let alone the rest of the type_path
2808 log_debug(redefine, class, annotation)("length() is too small for a type_path");
2809 return false;
2810 }
2811
2812 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2813 byte_i_ref += 1;
2814
2815 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
2816
2817 int calc_path_length = 0;
2818 for (; calc_path_length < path_length; calc_path_length++) {
2819 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2820 // not enough room for a path
2821 log_debug(redefine, class, annotation)
2822 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
2823 return false;
2824 }
2825
2826 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2827 byte_i_ref += 1;
2828 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2829 byte_i_ref += 1;
2830
2831 log_debug(redefine, class, annotation)
2832 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2833 calc_path_length, type_path_kind, type_argument_index);
2834
2835 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2836 // not enough room for a path
2837 log_debug(redefine, class, annotation)("inconsistent type_path values");
2838 return false;
2839 }
2840 }
2841 assert(path_length == calc_path_length, "sanity check");
2842
2843 return true;
2844 } // end skip_type_annotation_type_path()
2845
2846
2847 // Rewrite constant pool references in the method's stackmap table.
2848 // These "structures" are adapted from the StackMapTable_attribute that
2849 // is described in section 4.8.4 of the 6.0 version of the VM spec
2850 // (dated 2005.10.26):
2851 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2852 //
2853 // stack_map {
2854 // u2 number_of_entries;
2855 // stack_map_frame entries[number_of_entries];
2856 // }
2857 //
2858 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2859 const methodHandle& method, TRAPS) {
2860
2861 if (!method->has_stackmap_table()) {
2862 return;
2863 }
2864
2865 AnnotationArray* stackmap_data = method->stackmap_data();
2866 address stackmap_p = (address)stackmap_data->adr_at(0);
2867 address stackmap_end = stackmap_p + stackmap_data->length();
2868
2869 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2870 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2871 stackmap_p += 2;
2872
2873 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
2874
2875 // walk through each stack_map_frame
2876 u2 calc_number_of_entries = 0;
2877 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2878 // The stack_map_frame structure is a u1 frame_type followed by
2879 // 0 or more bytes of data:
2880 //
2881 // union stack_map_frame {
2882 // same_frame;
2883 // same_locals_1_stack_item_frame;
2884 // same_locals_1_stack_item_frame_extended;
2885 // chop_frame;
2886 // same_frame_extended;
2887 // append_frame;
2888 // full_frame;
2889 // }
2890
2891 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2892 u1 frame_type = *stackmap_p;
2893 stackmap_p++;
2894
2895 // same_frame {
2896 // u1 frame_type = SAME; /* 0-63 */
2897 // }
2898 if (frame_type <= 63) {
2899 // nothing more to do for same_frame
2900 }
2901
2902 // same_locals_1_stack_item_frame {
2903 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2904 // verification_type_info stack[1];
2905 // }
2906 else if (frame_type >= 64 && frame_type <= 127) {
2907 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2908 calc_number_of_entries, frame_type, THREAD);
2909 }
2910
2911 // reserved for future use
2912 else if (frame_type >= 128 && frame_type <= 246) {
2913 // nothing more to do for reserved frame_types
2914 }
2915
2916 // same_locals_1_stack_item_frame_extended {
2917 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2918 // u2 offset_delta;
2919 // verification_type_info stack[1];
2920 // }
2921 else if (frame_type == 247) {
2922 stackmap_p += 2;
2923 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2924 calc_number_of_entries, frame_type, THREAD);
2925 }
2926
2927 // chop_frame {
2928 // u1 frame_type = CHOP; /* 248-250 */
2929 // u2 offset_delta;
2930 // }
2931 else if (frame_type >= 248 && frame_type <= 250) {
2932 stackmap_p += 2;
2933 }
2934
2935 // same_frame_extended {
2936 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2937 // u2 offset_delta;
2938 // }
2939 else if (frame_type == 251) {
2940 stackmap_p += 2;
2941 }
2942
2943 // append_frame {
2944 // u1 frame_type = APPEND; /* 252-254 */
2945 // u2 offset_delta;
2946 // verification_type_info locals[frame_type - 251];
2947 // }
2948 else if (frame_type >= 252 && frame_type <= 254) {
2949 assert(stackmap_p + 2 <= stackmap_end,
2950 "no room for offset_delta");
2951 stackmap_p += 2;
2952 u1 len = frame_type - 251;
2953 for (u1 i = 0; i < len; i++) {
2954 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2955 calc_number_of_entries, frame_type, THREAD);
2956 }
2957 }
2958
2959 // full_frame {
2960 // u1 frame_type = FULL_FRAME; /* 255 */
2961 // u2 offset_delta;
2962 // u2 number_of_locals;
2963 // verification_type_info locals[number_of_locals];
2964 // u2 number_of_stack_items;
2965 // verification_type_info stack[number_of_stack_items];
2966 // }
2967 else if (frame_type == 255) {
2968 assert(stackmap_p + 2 + 2 <= stackmap_end,
2969 "no room for smallest full_frame");
2970 stackmap_p += 2;
2971
2972 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2973 stackmap_p += 2;
2974
2975 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2976 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2977 calc_number_of_entries, frame_type, THREAD);
2978 }
2979
2980 // Use the largest size for the number_of_stack_items, but only get
2981 // the right number of bytes.
2982 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2983 stackmap_p += 2;
2984
2985 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2986 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2987 calc_number_of_entries, frame_type, THREAD);
2988 }
2989 }
2990 } // end while there is a stack_map_frame
2991 assert(number_of_entries == calc_number_of_entries, "sanity check");
2992 } // end rewrite_cp_refs_in_stack_map_table()
2993
2994
2995 // Rewrite constant pool references in the verification type info
2996 // portion of the method's stackmap table. These "structures" are
2997 // adapted from the StackMapTable_attribute that is described in
2998 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2999 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3000 //
3001 // The verification_type_info structure is a u1 tag followed by 0 or
3002 // more bytes of data:
3003 //
3004 // union verification_type_info {
3005 // Top_variable_info;
3006 // Integer_variable_info;
3007 // Float_variable_info;
3008 // Long_variable_info;
3009 // Double_variable_info;
3010 // Null_variable_info;
3011 // UninitializedThis_variable_info;
3012 // Object_variable_info;
3013 // Uninitialized_variable_info;
3014 // }
3015 //
3016 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3017 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3018 u1 frame_type, TRAPS) {
3019
3020 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3021 u1 tag = *stackmap_p_ref;
3022 stackmap_p_ref++;
3023
3024 switch (tag) {
3025 // Top_variable_info {
3026 // u1 tag = ITEM_Top; /* 0 */
3027 // }
3028 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3029 case 0: // fall through
3030
3031 // Integer_variable_info {
3032 // u1 tag = ITEM_Integer; /* 1 */
3033 // }
3034 case ITEM_Integer: // fall through
3035
3036 // Float_variable_info {
3037 // u1 tag = ITEM_Float; /* 2 */
3038 // }
3039 case ITEM_Float: // fall through
3040
3041 // Double_variable_info {
3042 // u1 tag = ITEM_Double; /* 3 */
3043 // }
3044 case ITEM_Double: // fall through
3045
3046 // Long_variable_info {
3047 // u1 tag = ITEM_Long; /* 4 */
3048 // }
3049 case ITEM_Long: // fall through
3050
3051 // Null_variable_info {
3052 // u1 tag = ITEM_Null; /* 5 */
3053 // }
3054 case ITEM_Null: // fall through
3055
3056 // UninitializedThis_variable_info {
3057 // u1 tag = ITEM_UninitializedThis; /* 6 */
3058 // }
3059 case ITEM_UninitializedThis:
3060 // nothing more to do for the above tag types
3061 break;
3062
3063 // Object_variable_info {
3064 // u1 tag = ITEM_Object; /* 7 */
3065 // u2 cpool_index;
3066 // }
3067 case ITEM_Object:
3068 {
3069 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3070 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3071 u2 new_cp_index = find_new_index(cpool_index);
3072 if (new_cp_index != 0) {
3073 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3074 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3075 cpool_index = new_cp_index;
3076 }
3077 stackmap_p_ref += 2;
3078
3079 log_debug(redefine, class, stackmap)
3080 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3081 } break;
3082
3083 // Uninitialized_variable_info {
3084 // u1 tag = ITEM_Uninitialized; /* 8 */
3085 // u2 offset;
3086 // }
3087 case ITEM_Uninitialized:
3088 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3089 stackmap_p_ref += 2;
3090 break;
3091
3092 default:
3093 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3094 ShouldNotReachHere();
3095 break;
3096 } // end switch (tag)
3097 } // end rewrite_cp_refs_in_verification_type_info()
3098
3099
3100 // Change the constant pool associated with klass scratch_class to
3101 // scratch_cp. If shrink is true, then scratch_cp_length elements
3102 // are copied from scratch_cp to a smaller constant pool and the
3103 // smaller constant pool is associated with scratch_class.
3104 void VM_RedefineClasses::set_new_constant_pool(
3105 ClassLoaderData* loader_data,
3106 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3107 int scratch_cp_length, TRAPS) {
3108 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3109
3110 // scratch_cp is a merged constant pool and has enough space for a
3111 // worst case merge situation. We want to associate the minimum
3112 // sized constant pool with the klass to save space.
3113 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3114 constantPoolHandle smaller_cp(THREAD, cp);
3115
3116 // preserve version() value in the smaller copy
3117 int version = scratch_cp->version();
3118 assert(version != 0, "sanity check");
3119 smaller_cp->set_version(version);
3120
3121 // attach klass to new constant pool
3122 // reference to the cp holder is needed for copy_operands()
3123 smaller_cp->set_pool_holder(scratch_class);
3124
3125 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3126 if (HAS_PENDING_EXCEPTION) {
3127 // Exception is handled in the caller
3128 loader_data->add_to_deallocate_list(smaller_cp());
3129 return;
3130 }
3131 scratch_cp = smaller_cp;
3132
3133 // attach new constant pool to klass
3134 scratch_class->set_constants(scratch_cp());
3135 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3136
3137 int i; // for portability
3138
3139 // update each field in klass to use new constant pool indices as needed
3140 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3141 jshort cur_index = fs.name_index();
3142 jshort new_index = find_new_index(cur_index);
3143 if (new_index != 0) {
3144 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3145 fs.set_name_index(new_index);
3146 }
3147 cur_index = fs.signature_index();
3148 new_index = find_new_index(cur_index);
3149 if (new_index != 0) {
3150 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3151 fs.set_signature_index(new_index);
3152 }
3153 cur_index = fs.initval_index();
3154 new_index = find_new_index(cur_index);
3155 if (new_index != 0) {
3156 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3157 fs.set_initval_index(new_index);
3158 }
3159 cur_index = fs.generic_signature_index();
3160 new_index = find_new_index(cur_index);
3161 if (new_index != 0) {
3162 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3163 fs.set_generic_signature_index(new_index);
3164 }
3165 } // end for each field
3166
3167 // Update constant pool indices in the inner classes info to use
3168 // new constant indices as needed. The inner classes info is a
3169 // quadruple:
3170 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3171 InnerClassesIterator iter(scratch_class);
3172 for (; !iter.done(); iter.next()) {
3173 int cur_index = iter.inner_class_info_index();
3174 if (cur_index == 0) {
3175 continue; // JVM spec. allows null inner class refs so skip it
3176 }
3177 int new_index = find_new_index(cur_index);
3178 if (new_index != 0) {
3179 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3180 iter.set_inner_class_info_index(new_index);
3181 }
3182 cur_index = iter.outer_class_info_index();
3183 new_index = find_new_index(cur_index);
3184 if (new_index != 0) {
3185 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3186 iter.set_outer_class_info_index(new_index);
3187 }
3188 cur_index = iter.inner_name_index();
3189 new_index = find_new_index(cur_index);
3190 if (new_index != 0) {
3191 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3192 iter.set_inner_name_index(new_index);
3193 }
3194 } // end for each inner class
3195
3196 // Attach each method in klass to the new constant pool and update
3197 // to use new constant pool indices as needed:
3198 Array<Method*>* methods = scratch_class->methods();
3199 for (i = methods->length() - 1; i >= 0; i--) {
3200 methodHandle method(THREAD, methods->at(i));
3201 method->set_constants(scratch_cp());
3202
3203 int new_index = find_new_index(method->name_index());
3204 if (new_index != 0) {
3205 log_trace(redefine, class, constantpool)
3206 ("method-name_index change: %d to %d", method->name_index(), new_index);
3207 method->set_name_index(new_index);
3208 }
3209 new_index = find_new_index(method->signature_index());
3210 if (new_index != 0) {
3211 log_trace(redefine, class, constantpool)
3212 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3213 method->set_signature_index(new_index);
3214 }
3215 new_index = find_new_index(method->generic_signature_index());
3216 if (new_index != 0) {
3217 log_trace(redefine, class, constantpool)
3218 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3219 method->set_generic_signature_index(new_index);
3220 }
3221
3222 // Update constant pool indices in the method's checked exception
3223 // table to use new constant indices as needed.
3224 int cext_length = method->checked_exceptions_length();
3225 if (cext_length > 0) {
3226 CheckedExceptionElement * cext_table =
3227 method->checked_exceptions_start();
3228 for (int j = 0; j < cext_length; j++) {
3229 int cur_index = cext_table[j].class_cp_index;
3230 int new_index = find_new_index(cur_index);
3231 if (new_index != 0) {
3232 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3233 cext_table[j].class_cp_index = (u2)new_index;
3234 }
3235 } // end for each checked exception table entry
3236 } // end if there are checked exception table entries
3237
3238 // Update each catch type index in the method's exception table
3239 // to use new constant pool indices as needed. The exception table
3240 // holds quadruple entries of the form:
3241 // (beg_bci, end_bci, handler_bci, klass_index)
3242
3243 ExceptionTable ex_table(method());
3244 int ext_length = ex_table.length();
3245
3246 for (int j = 0; j < ext_length; j ++) {
3247 int cur_index = ex_table.catch_type_index(j);
3248 int new_index = find_new_index(cur_index);
3249 if (new_index != 0) {
3250 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3251 ex_table.set_catch_type_index(j, new_index);
3252 }
3253 } // end for each exception table entry
3254
3255 // Update constant pool indices in the method's local variable
3256 // table to use new constant indices as needed. The local variable
3257 // table hold sextuple entries of the form:
3258 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3259 int lvt_length = method->localvariable_table_length();
3260 if (lvt_length > 0) {
3261 LocalVariableTableElement * lv_table =
3262 method->localvariable_table_start();
3263 for (int j = 0; j < lvt_length; j++) {
3264 int cur_index = lv_table[j].name_cp_index;
3265 int new_index = find_new_index(cur_index);
3266 if (new_index != 0) {
3267 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3268 lv_table[j].name_cp_index = (u2)new_index;
3269 }
3270 cur_index = lv_table[j].descriptor_cp_index;
3271 new_index = find_new_index(cur_index);
3272 if (new_index != 0) {
3273 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3274 lv_table[j].descriptor_cp_index = (u2)new_index;
3275 }
3276 cur_index = lv_table[j].signature_cp_index;
3277 new_index = find_new_index(cur_index);
3278 if (new_index != 0) {
3279 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3280 lv_table[j].signature_cp_index = (u2)new_index;
3281 }
3282 } // end for each local variable table entry
3283 } // end if there are local variable table entries
3284
3285 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3286 } // end for each method
3287 } // end set_new_constant_pool()
3288
3289
3290 // Unevolving classes may point to methods of the_class directly
3291 // from their constant pool caches, itables, and/or vtables. We
3292 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3293 // to fix up these pointers.
3294
3295 // Adjust cpools and vtables closure
3296 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3297
3298 // This is a very busy routine. We don't want too much tracing
3299 // printed out.
3300 bool trace_name_printed = false;
3301 InstanceKlass *the_class = InstanceKlass::cast(_the_class);
3302
3303 // If the class being redefined is java.lang.Object, we need to fix all
3304 // array class vtables also
3305 if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) {
3306 k->vtable().adjust_method_entries(the_class, &trace_name_printed);
3307
3308 } else if (k->is_instance_klass()) {
3309 HandleMark hm(_thread);
3310 InstanceKlass *ik = InstanceKlass::cast(k);
3311
3312 // HotSpot specific optimization! HotSpot does not currently
3313 // support delegation from the bootstrap class loader to a
3314 // user-defined class loader. This means that if the bootstrap
3315 // class loader is the initiating class loader, then it will also
3316 // be the defining class loader. This also means that classes
3317 // loaded by the bootstrap class loader cannot refer to classes
3318 // loaded by a user-defined class loader. Note: a user-defined
3319 // class loader can delegate to the bootstrap class loader.
3320 //
3321 // If the current class being redefined has a user-defined class
3322 // loader as its defining class loader, then we can skip all
3323 // classes loaded by the bootstrap class loader.
3324 bool is_user_defined = (_the_class->class_loader() != NULL);
3325 if (is_user_defined && ik->class_loader() == NULL) {
3326 return;
3327 }
3328
3329 // Fix the vtable embedded in the_class and subclasses of the_class,
3330 // if one exists. We discard scratch_class and we don't keep an
3331 // InstanceKlass around to hold obsolete methods so we don't have
3332 // any other InstanceKlass embedded vtables to update. The vtable
3333 // holds the Method*s for virtual (but not final) methods.
3334 // Default methods, or concrete methods in interfaces are stored
3335 // in the vtable, so if an interface changes we need to check
3336 // adjust_method_entries() for every InstanceKlass, which will also
3337 // adjust the default method vtable indices.
3338 // We also need to adjust any default method entries that are
3339 // not yet in the vtable, because the vtable setup is in progress.
3340 // This must be done after we adjust the default_methods and
3341 // default_vtable_indices for methods already in the vtable.
3342 // If redefining Unsafe, walk all the vtables looking for entries.
3343 if (ik->vtable_length() > 0 && (_the_class->is_interface()
3344 || _the_class == SystemDictionary::internal_Unsafe_klass()
3345 || ik->is_subtype_of(_the_class))) {
3346 // ik->vtable() creates a wrapper object; rm cleans it up
3347 ResourceMark rm(_thread);
3348
3349 ik->vtable().adjust_method_entries(the_class, &trace_name_printed);
3350 ik->adjust_default_methods(the_class, &trace_name_printed);
3351 }
3352
3353 // If the current class has an itable and we are either redefining an
3354 // interface or if the current class is a subclass of the_class, then
3355 // we potentially have to fix the itable. If we are redefining an
3356 // interface, then we have to call adjust_method_entries() for
3357 // every InstanceKlass that has an itable since there isn't a
3358 // subclass relationship between an interface and an InstanceKlass.
3359 // If redefining Unsafe, walk all the itables looking for entries.
3360 if (ik->itable_length() > 0 && (_the_class->is_interface()
3361 || _the_class == SystemDictionary::internal_Unsafe_klass()
3362 || ik->is_subclass_of(_the_class))) {
3363 ResourceMark rm(_thread);
3364 ik->itable().adjust_method_entries(the_class, &trace_name_printed);
3365 }
3366
3367 // The constant pools in other classes (other_cp) can refer to
3368 // methods in the_class. We have to update method information in
3369 // other_cp's cache. If other_cp has a previous version, then we
3370 // have to repeat the process for each previous version. The
3371 // constant pool cache holds the Method*s for non-virtual
3372 // methods and for virtual, final methods.
3373 //
3374 // Special case: if the current class is the_class, then new_cp
3375 // has already been attached to the_class and old_cp has already
3376 // been added as a previous version. The new_cp doesn't have any
3377 // cached references to old methods so it doesn't need to be
3378 // updated. We can simply start with the previous version(s) in
3379 // that case.
3380 constantPoolHandle other_cp;
3381 ConstantPoolCache* cp_cache;
3382
3383 if (ik != _the_class) {
3384 // this klass' constant pool cache may need adjustment
3385 other_cp = constantPoolHandle(ik->constants());
3386 cp_cache = other_cp->cache();
3387 if (cp_cache != NULL) {
3388 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3389 }
3390 }
3391
3392 // the previous versions' constant pool caches may need adjustment
3393 for (InstanceKlass* pv_node = ik->previous_versions();
3394 pv_node != NULL;
3395 pv_node = pv_node->previous_versions()) {
3396 cp_cache = pv_node->constants()->cache();
3397 if (cp_cache != NULL) {
3398 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3399 }
3400 }
3401 }
3402 }
3403
3404 // Clean method data for this class
3405 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3406 if (k->is_instance_klass()) {
3407 InstanceKlass *ik = InstanceKlass::cast(k);
3408 // Clean MethodData of this class's methods so they don't refer to
3409 // old methods that are no longer running.
3410 Array<Method*>* methods = ik->methods();
3411 int num_methods = methods->length();
3412 for (int index = 0; index < num_methods; ++index) {
3413 if (methods->at(index)->method_data() != NULL) {
3414 methods->at(index)->method_data()->clean_weak_method_links();
3415 }
3416 }
3417 }
3418 }
3419
3420 void VM_RedefineClasses::update_jmethod_ids() {
3421 for (int j = 0; j < _matching_methods_length; ++j) {
3422 Method* old_method = _matching_old_methods[j];
3423 jmethodID jmid = old_method->find_jmethod_id_or_null();
3424 if (jmid != NULL) {
3425 // There is a jmethodID, change it to point to the new method
3426 methodHandle new_method_h(_matching_new_methods[j]);
3427 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3428 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3429 "should be replaced");
3430 }
3431 }
3432 }
3433
3434 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3435 int emcp_method_count = 0;
3436 int obsolete_count = 0;
3437 int old_index = 0;
3438 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3439 Method* old_method = _matching_old_methods[j];
3440 Method* new_method = _matching_new_methods[j];
3441 Method* old_array_method;
3442
3443 // Maintain an old_index into the _old_methods array by skipping
3444 // deleted methods
3445 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3446 ++old_index;
3447 }
3448
3449 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3450 // The EMCP definition from JSR-163 requires the bytecodes to be
3451 // the same with the exception of constant pool indices which may
3452 // differ. However, the constants referred to by those indices
3453 // must be the same.
3454 //
3455 // We use methods_EMCP() for comparison since constant pool
3456 // merging can remove duplicate constant pool entries that were
3457 // present in the old method and removed from the rewritten new
3458 // method. A faster binary comparison function would consider the
3459 // old and new methods to be different when they are actually
3460 // EMCP.
3461 //
3462 // The old and new methods are EMCP and you would think that we
3463 // could get rid of one of them here and now and save some space.
3464 // However, the concept of EMCP only considers the bytecodes and
3465 // the constant pool entries in the comparison. Other things,
3466 // e.g., the line number table (LNT) or the local variable table
3467 // (LVT) don't count in the comparison. So the new (and EMCP)
3468 // method can have a new LNT that we need so we can't just
3469 // overwrite the new method with the old method.
3470 //
3471 // When this routine is called, we have already attached the new
3472 // methods to the_class so the old methods are effectively
3473 // overwritten. However, if an old method is still executing,
3474 // then the old method cannot be collected until sometime after
3475 // the old method call has returned. So the overwriting of old
3476 // methods by new methods will save us space except for those
3477 // (hopefully few) old methods that are still executing.
3478 //
3479 // A method refers to a ConstMethod* and this presents another
3480 // possible avenue to space savings. The ConstMethod* in the
3481 // new method contains possibly new attributes (LNT, LVT, etc).
3482 // At first glance, it seems possible to save space by replacing
3483 // the ConstMethod* in the old method with the ConstMethod*
3484 // from the new method. The old and new methods would share the
3485 // same ConstMethod* and we would save the space occupied by
3486 // the old ConstMethod*. However, the ConstMethod* contains
3487 // a back reference to the containing method. Sharing the
3488 // ConstMethod* between two methods could lead to confusion in
3489 // the code that uses the back reference. This would lead to
3490 // brittle code that could be broken in non-obvious ways now or
3491 // in the future.
3492 //
3493 // Another possibility is to copy the ConstMethod* from the new
3494 // method to the old method and then overwrite the new method with
3495 // the old method. Since the ConstMethod* contains the bytecodes
3496 // for the method embedded in the oop, this option would change
3497 // the bytecodes out from under any threads executing the old
3498 // method and make the thread's bcp invalid. Since EMCP requires
3499 // that the bytecodes be the same modulo constant pool indices, it
3500 // is straight forward to compute the correct new bcp in the new
3501 // ConstMethod* from the old bcp in the old ConstMethod*. The
3502 // time consuming part would be searching all the frames in all
3503 // of the threads to find all of the calls to the old method.
3504 //
3505 // It looks like we will have to live with the limited savings
3506 // that we get from effectively overwriting the old methods
3507 // when the new methods are attached to the_class.
3508
3509 // Count number of methods that are EMCP. The method will be marked
3510 // old but not obsolete if it is EMCP.
3511 emcp_method_count++;
3512
3513 // An EMCP method is _not_ obsolete. An obsolete method has a
3514 // different jmethodID than the current method. An EMCP method
3515 // has the same jmethodID as the current method. Having the
3516 // same jmethodID for all EMCP versions of a method allows for
3517 // a consistent view of the EMCP methods regardless of which
3518 // EMCP method you happen to have in hand. For example, a
3519 // breakpoint set in one EMCP method will work for all EMCP
3520 // versions of the method including the current one.
3521 } else {
3522 // mark obsolete methods as such
3523 old_method->set_is_obsolete();
3524 obsolete_count++;
3525
3526 // obsolete methods need a unique idnum so they become new entries in
3527 // the jmethodID cache in InstanceKlass
3528 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3529 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3530 if (num != ConstMethod::UNSET_IDNUM) {
3531 old_method->set_method_idnum(num);
3532 }
3533
3534 // With tracing we try not to "yack" too much. The position of
3535 // this trace assumes there are fewer obsolete methods than
3536 // EMCP methods.
3537 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3538 ResourceMark rm;
3539 log_trace(redefine, class, obsolete, mark)
3540 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3541 }
3542 }
3543 old_method->set_is_old();
3544 }
3545 for (int i = 0; i < _deleted_methods_length; ++i) {
3546 Method* old_method = _deleted_methods[i];
3547
3548 assert(!old_method->has_vtable_index(),
3549 "cannot delete methods with vtable entries");;
3550
3551 // Mark all deleted methods as old, obsolete and deleted
3552 old_method->set_is_deleted();
3553 old_method->set_is_old();
3554 old_method->set_is_obsolete();
3555 ++obsolete_count;
3556 // With tracing we try not to "yack" too much. The position of
3557 // this trace assumes there are fewer obsolete methods than
3558 // EMCP methods.
3559 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3560 ResourceMark rm;
3561 log_trace(redefine, class, obsolete, mark)
3562 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3563 }
3564 }
3565 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3566 "sanity check");
3567 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3568 return emcp_method_count;
3569 }
3570
3571 // This internal class transfers the native function registration from old methods
3572 // to new methods. It is designed to handle both the simple case of unchanged
3573 // native methods and the complex cases of native method prefixes being added and/or
3574 // removed.
3575 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3576 //
3577 // This class is used after the new methods have been installed in "the_class".
3578 //
3579 // So, for example, the following must be handled. Where 'm' is a method and
3580 // a number followed by an underscore is a prefix.
3581 //
3582 // Old Name New Name
3583 // Simple transfer to new method m -> m
3584 // Add prefix m -> 1_m
3585 // Remove prefix 1_m -> m
3586 // Simultaneous add of prefixes m -> 3_2_1_m
3587 // Simultaneous removal of prefixes 3_2_1_m -> m
3588 // Simultaneous add and remove 1_m -> 2_m
3589 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3590 //
3591 class TransferNativeFunctionRegistration {
3592 private:
3593 InstanceKlass* the_class;
3594 int prefix_count;
3595 char** prefixes;
3596
3597 // Recursively search the binary tree of possibly prefixed method names.
3598 // Iteration could be used if all agents were well behaved. Full tree walk is
3599 // more resilent to agents not cleaning up intermediate methods.
3600 // Branch at each depth in the binary tree is:
3601 // (1) without the prefix.
3602 // (2) with the prefix.
3603 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3604 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3605 Symbol* signature) {
3606 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3607 if (name_symbol != NULL) {
3608 Method* method = the_class->lookup_method(name_symbol, signature);
3609 if (method != NULL) {
3610 // Even if prefixed, intermediate methods must exist.
3611 if (method->is_native()) {
3612 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3613 return method;
3614 }
3615 if (depth < prefix_count) {
3616 // Try applying further prefixes (other than this one).
3617 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3618 if (method != NULL) {
3619 return method; // found
3620 }
3621
3622 // Try adding this prefix to the method name and see if it matches
3623 // another method name.
3624 char* prefix = prefixes[depth];
3625 size_t prefix_len = strlen(prefix);
3626 size_t trial_len = name_len + prefix_len;
3627 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3628 strcpy(trial_name_str, prefix);
3629 strcat(trial_name_str, name_str);
3630 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3631 signature);
3632 if (method != NULL) {
3633 // If found along this branch, it was prefixed, mark as such
3634 method->set_is_prefixed_native();
3635 return method; // found
3636 }
3637 }
3638 }
3639 }
3640 return NULL; // This whole branch bore nothing
3641 }
3642
3643 // Return the method name with old prefixes stripped away.
3644 char* method_name_without_prefixes(Method* method) {
3645 Symbol* name = method->name();
3646 char* name_str = name->as_utf8();
3647
3648 // Old prefixing may be defunct, strip prefixes, if any.
3649 for (int i = prefix_count-1; i >= 0; i--) {
3650 char* prefix = prefixes[i];
3651 size_t prefix_len = strlen(prefix);
3652 if (strncmp(prefix, name_str, prefix_len) == 0) {
3653 name_str += prefix_len;
3654 }
3655 }
3656 return name_str;
3657 }
3658
3659 // Strip any prefixes off the old native method, then try to find a
3660 // (possibly prefixed) new native that matches it.
3661 Method* strip_and_search_for_new_native(Method* method) {
3662 ResourceMark rm;
3663 char* name_str = method_name_without_prefixes(method);
3664 return search_prefix_name_space(0, name_str, strlen(name_str),
3665 method->signature());
3666 }
3667
3668 public:
3669
3670 // Construct a native method transfer processor for this class.
3671 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3672 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3673
3674 the_class = _the_class;
3675 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3676 }
3677
3678 // Attempt to transfer any of the old or deleted methods that are native
3679 void transfer_registrations(Method** old_methods, int methods_length) {
3680 for (int j = 0; j < methods_length; j++) {
3681 Method* old_method = old_methods[j];
3682
3683 if (old_method->is_native() && old_method->has_native_function()) {
3684 Method* new_method = strip_and_search_for_new_native(old_method);
3685 if (new_method != NULL) {
3686 // Actually set the native function in the new method.
3687 // Redefine does not send events (except CFLH), certainly not this
3688 // behind the scenes re-registration.
3689 new_method->set_native_function(old_method->native_function(),
3690 !Method::native_bind_event_is_interesting);
3691 }
3692 }
3693 }
3694 }
3695 };
3696
3697 // Don't lose the association between a native method and its JNI function.
3698 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3699 TransferNativeFunctionRegistration transfer(the_class);
3700 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3701 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3702 }
3703
3704 // Deoptimize all compiled code that depends on this class.
3705 //
3706 // If the can_redefine_classes capability is obtained in the onload
3707 // phase then the compiler has recorded all dependencies from startup.
3708 // In that case we need only deoptimize and throw away all compiled code
3709 // that depends on the class.
3710 //
3711 // If can_redefine_classes is obtained sometime after the onload
3712 // phase then the dependency information may be incomplete. In that case
3713 // the first call to RedefineClasses causes all compiled code to be
3714 // thrown away. As can_redefine_classes has been obtained then
3715 // all future compilations will record dependencies so second and
3716 // subsequent calls to RedefineClasses need only throw away code
3717 // that depends on the class.
3718 //
3719 void VM_RedefineClasses::flush_dependent_code(InstanceKlass* ik, TRAPS) {
3720 assert_locked_or_safepoint(Compile_lock);
3721
3722 // All dependencies have been recorded from startup or this is a second or
3723 // subsequent use of RedefineClasses
3724 if (JvmtiExport::all_dependencies_are_recorded()) {
3725 CodeCache::flush_evol_dependents_on(ik);
3726 } else {
3727 CodeCache::mark_all_nmethods_for_deoptimization();
3728
3729 ResourceMark rm(THREAD);
3730 DeoptimizationMarker dm;
3731
3732 // Deoptimize all activations depending on marked nmethods
3733 Deoptimization::deoptimize_dependents();
3734
3735 // Make the dependent methods not entrant
3736 CodeCache::make_marked_nmethods_not_entrant();
3737
3738 // From now on we know that the dependency information is complete
3739 JvmtiExport::set_all_dependencies_are_recorded(true);
3740 }
3741 }
3742
3743 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3744 Method* old_method;
3745 Method* new_method;
3746
3747 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3748 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3749 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3750 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3751
3752 _matching_methods_length = 0;
3753 _deleted_methods_length = 0;
3754 _added_methods_length = 0;
3755
3756 int nj = 0;
3757 int oj = 0;
3758 while (true) {
3759 if (oj >= _old_methods->length()) {
3760 if (nj >= _new_methods->length()) {
3761 break; // we've looked at everything, done
3762 }
3763 // New method at the end
3764 new_method = _new_methods->at(nj);
3765 _added_methods[_added_methods_length++] = new_method;
3766 ++nj;
3767 } else if (nj >= _new_methods->length()) {
3768 // Old method, at the end, is deleted
3769 old_method = _old_methods->at(oj);
3770 _deleted_methods[_deleted_methods_length++] = old_method;
3771 ++oj;
3772 } else {
3773 old_method = _old_methods->at(oj);
3774 new_method = _new_methods->at(nj);
3775 if (old_method->name() == new_method->name()) {
3776 if (old_method->signature() == new_method->signature()) {
3777 _matching_old_methods[_matching_methods_length ] = old_method;
3778 _matching_new_methods[_matching_methods_length++] = new_method;
3779 ++nj;
3780 ++oj;
3781 } else {
3782 // added overloaded have already been moved to the end,
3783 // so this is a deleted overloaded method
3784 _deleted_methods[_deleted_methods_length++] = old_method;
3785 ++oj;
3786 }
3787 } else { // names don't match
3788 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3789 // new method
3790 _added_methods[_added_methods_length++] = new_method;
3791 ++nj;
3792 } else {
3793 // deleted method
3794 _deleted_methods[_deleted_methods_length++] = old_method;
3795 ++oj;
3796 }
3797 }
3798 }
3799 }
3800 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3801 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3802 }
3803
3804
3805 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
3806 InstanceKlass* scratch_class) {
3807 // Swap annotation fields values
3808 Annotations* old_annotations = the_class->annotations();
3809 the_class->set_annotations(scratch_class->annotations());
3810 scratch_class->set_annotations(old_annotations);
3811 }
3812
3813
3814 // Install the redefinition of a class:
3815 // - house keeping (flushing breakpoints and caches, deoptimizing
3816 // dependent compiled code)
3817 // - replacing parts in the_class with parts from scratch_class
3818 // - adding a weak reference to track the obsolete but interesting
3819 // parts of the_class
3820 // - adjusting constant pool caches and vtables in other classes
3821 // that refer to methods in the_class. These adjustments use the
3822 // ClassLoaderDataGraph::classes_do() facility which only allows
3823 // a helper method to be specified. The interesting parameters
3824 // that we would like to pass to the helper method are saved in
3825 // static global fields in the VM operation.
3826 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3827 InstanceKlass* scratch_class, TRAPS) {
3828
3829 HandleMark hm(THREAD); // make sure handles from this call are freed
3830
3831 if (log_is_enabled(Info, redefine, class, timer)) {
3832 _timer_rsc_phase1.start();
3833 }
3834
3835 InstanceKlass* the_class = get_ik(the_jclass);
3836
3837 // Remove all breakpoints in methods of this class
3838 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3839 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
3840
3841 // Deoptimize all compiled code that depends on this class
3842 flush_dependent_code(the_class, THREAD);
3843
3844 _old_methods = the_class->methods();
3845 _new_methods = scratch_class->methods();
3846 _the_class = the_class;
3847 compute_added_deleted_matching_methods();
3848 update_jmethod_ids();
3849
3850 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
3851
3852 // Attach new constant pool to the original klass. The original
3853 // klass still refers to the old constant pool (for now).
3854 scratch_class->constants()->set_pool_holder(the_class);
3855
3856 #if 0
3857 // In theory, with constant pool merging in place we should be able
3858 // to save space by using the new, merged constant pool in place of
3859 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3860 // the klass version we are replacing now and any constant pool(s) in
3861 // previous versions of klass. Nice theory, doesn't work in practice.
3862 // When this code is enabled, even simple programs throw NullPointer
3863 // exceptions. I'm guessing that this is caused by some constant pool
3864 // cache difference between the new, merged constant pool and the
3865 // constant pool that was just being used by the klass. I'm keeping
3866 // this code around to archive the idea, but the code has to remain
3867 // disabled for now.
3868
3869 // Attach each old method to the new constant pool. This can be
3870 // done here since we are past the bytecode verification and
3871 // constant pool optimization phases.
3872 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3873 Method* method = _old_methods->at(i);
3874 method->set_constants(scratch_class->constants());
3875 }
3876
3877 // NOTE: this doesn't work because you can redefine the same class in two
3878 // threads, each getting their own constant pool data appended to the
3879 // original constant pool. In order for the new methods to work when they
3880 // become old methods, they need to keep their updated copy of the constant pool.
3881
3882 {
3883 // walk all previous versions of the klass
3884 InstanceKlass *ik = the_class;
3885 PreviousVersionWalker pvw(ik);
3886 do {
3887 ik = pvw.next_previous_version();
3888 if (ik != NULL) {
3889
3890 // attach previous version of klass to the new constant pool
3891 ik->set_constants(scratch_class->constants());
3892
3893 // Attach each method in the previous version of klass to the
3894 // new constant pool
3895 Array<Method*>* prev_methods = ik->methods();
3896 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3897 Method* method = prev_methods->at(i);
3898 method->set_constants(scratch_class->constants());
3899 }
3900 }
3901 } while (ik != NULL);
3902 }
3903 #endif
3904
3905 // Replace methods and constantpool
3906 the_class->set_methods(_new_methods);
3907 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3908 // and to be able to undo operation easily.
3909
3910 Array<int>* old_ordering = the_class->method_ordering();
3911 the_class->set_method_ordering(scratch_class->method_ordering());
3912 scratch_class->set_method_ordering(old_ordering);
3913
3914 ConstantPool* old_constants = the_class->constants();
3915 the_class->set_constants(scratch_class->constants());
3916 scratch_class->set_constants(old_constants); // See the previous comment.
3917 #if 0
3918 // We are swapping the guts of "the new class" with the guts of "the
3919 // class". Since the old constant pool has just been attached to "the
3920 // new class", it seems logical to set the pool holder in the old
3921 // constant pool also. However, doing this will change the observable
3922 // class hierarchy for any old methods that are still executing. A
3923 // method can query the identity of its "holder" and this query uses
3924 // the method's constant pool link to find the holder. The change in
3925 // holding class from "the class" to "the new class" can confuse
3926 // things.
3927 //
3928 // Setting the old constant pool's holder will also cause
3929 // verification done during vtable initialization below to fail.
3930 // During vtable initialization, the vtable's class is verified to be
3931 // a subtype of the method's holder. The vtable's class is "the
3932 // class" and the method's holder is gotten from the constant pool
3933 // link in the method itself. For "the class"'s directly implemented
3934 // methods, the method holder is "the class" itself (as gotten from
3935 // the new constant pool). The check works fine in this case. The
3936 // check also works fine for methods inherited from super classes.
3937 //
3938 // Miranda methods are a little more complicated. A miranda method is
3939 // provided by an interface when the class implementing the interface
3940 // does not provide its own method. These interfaces are implemented
3941 // internally as an InstanceKlass. These special instanceKlasses
3942 // share the constant pool of the class that "implements" the
3943 // interface. By sharing the constant pool, the method holder of a
3944 // miranda method is the class that "implements" the interface. In a
3945 // non-redefine situation, the subtype check works fine. However, if
3946 // the old constant pool's pool holder is modified, then the check
3947 // fails because there is no class hierarchy relationship between the
3948 // vtable's class and "the new class".
3949
3950 old_constants->set_pool_holder(scratch_class());
3951 #endif
3952
3953 // track number of methods that are EMCP for add_previous_version() call below
3954 int emcp_method_count = check_methods_and_mark_as_obsolete();
3955 transfer_old_native_function_registrations(the_class);
3956
3957 // The class file bytes from before any retransformable agents mucked
3958 // with them was cached on the scratch class, move to the_class.
3959 // Note: we still want to do this if nothing needed caching since it
3960 // should get cleared in the_class too.
3961 if (the_class->get_cached_class_file() == 0) {
3962 // the_class doesn't have a cache yet so copy it
3963 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3964 }
3965 else if (scratch_class->get_cached_class_file() !=
3966 the_class->get_cached_class_file()) {
3967 // The same class can be present twice in the scratch classes list or there
3968 // are multiple concurrent RetransformClasses calls on different threads.
3969 // In such cases we have to deallocate scratch_class cached_class_file.
3970 os::free(scratch_class->get_cached_class_file());
3971 }
3972
3973 // NULL out in scratch class to not delete twice. The class to be redefined
3974 // always owns these bytes.
3975 scratch_class->set_cached_class_file(NULL);
3976
3977 // Replace inner_classes
3978 Array<u2>* old_inner_classes = the_class->inner_classes();
3979 the_class->set_inner_classes(scratch_class->inner_classes());
3980 scratch_class->set_inner_classes(old_inner_classes);
3981
3982 // Initialize the vtable and interface table after
3983 // methods have been rewritten
3984 {
3985 ResourceMark rm(THREAD);
3986 // no exception should happen here since we explicitly
3987 // do not check loader constraints.
3988 // compare_and_normalize_class_versions has already checked:
3989 // - classloaders unchanged, signatures unchanged
3990 // - all instanceKlasses for redefined classes reused & contents updated
3991 the_class->vtable().initialize_vtable(false, THREAD);
3992 the_class->itable().initialize_itable(false, THREAD);
3993 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3994 }
3995
3996 // Leave arrays of jmethodIDs and itable index cache unchanged
3997
3998 // Copy the "source file name" attribute from new class version
3999 the_class->set_source_file_name_index(
4000 scratch_class->source_file_name_index());
4001
4002 // Copy the "source debug extension" attribute from new class version
4003 the_class->set_source_debug_extension(
4004 scratch_class->source_debug_extension(),
4005 scratch_class->source_debug_extension() == NULL ? 0 :
4006 (int)strlen(scratch_class->source_debug_extension()));
4007
4008 // Use of javac -g could be different in the old and the new
4009 if (scratch_class->access_flags().has_localvariable_table() !=
4010 the_class->access_flags().has_localvariable_table()) {
4011
4012 AccessFlags flags = the_class->access_flags();
4013 if (scratch_class->access_flags().has_localvariable_table()) {
4014 flags.set_has_localvariable_table();
4015 } else {
4016 flags.clear_has_localvariable_table();
4017 }
4018 the_class->set_access_flags(flags);
4019 }
4020
4021 swap_annotations(the_class, scratch_class);
4022
4023 // Replace minor version number of class file
4024 u2 old_minor_version = the_class->minor_version();
4025 the_class->set_minor_version(scratch_class->minor_version());
4026 scratch_class->set_minor_version(old_minor_version);
4027
4028 // Replace major version number of class file
4029 u2 old_major_version = the_class->major_version();
4030 the_class->set_major_version(scratch_class->major_version());
4031 scratch_class->set_major_version(old_major_version);
4032
4033 // Replace CP indexes for class and name+type of enclosing method
4034 u2 old_class_idx = the_class->enclosing_method_class_index();
4035 u2 old_method_idx = the_class->enclosing_method_method_index();
4036 the_class->set_enclosing_method_indices(
4037 scratch_class->enclosing_method_class_index(),
4038 scratch_class->enclosing_method_method_index());
4039 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4040
4041 // Replace fingerprint data
4042 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4043 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4044
4045 the_class->set_has_been_redefined();
4046
4047 if (!the_class->should_be_initialized()) {
4048 // Class was already initialized, so AOT has only seen the original version.
4049 // We need to let AOT look at it again.
4050 AOTLoader::load_for_klass(the_class, THREAD);
4051 }
4052
4053 // keep track of previous versions of this class
4054 the_class->add_previous_version(scratch_class, emcp_method_count);
4055
4056 _timer_rsc_phase1.stop();
4057 if (log_is_enabled(Info, redefine, class, timer)) {
4058 _timer_rsc_phase2.start();
4059 }
4060
4061 // Adjust constantpool caches and vtables for all classes
4062 // that reference methods of the evolved class.
4063 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4064 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4065
4066 if (the_class->oop_map_cache() != NULL) {
4067 // Flush references to any obsolete methods from the oop map cache
4068 // so that obsolete methods are not pinned.
4069 the_class->oop_map_cache()->flush_obsolete_entries();
4070 }
4071
4072 increment_class_counter((InstanceKlass *)the_class, THREAD);
4073 {
4074 ResourceMark rm(THREAD);
4075 // increment the classRedefinedCount field in the_class and in any
4076 // direct and indirect subclasses of the_class
4077 log_info(redefine, class, load)
4078 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4079 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4080 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4081 the_class->external_name(),
4082 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4083
4084 }
4085 _timer_rsc_phase2.stop();
4086 } // end redefine_single_class()
4087
4088
4089 // Increment the classRedefinedCount field in the specific InstanceKlass
4090 // and in all direct and indirect subclasses.
4091 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4092 oop class_mirror = ik->java_mirror();
4093 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4094 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4095 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4096
4097 if (class_oop != _the_class) {
4098 // _the_class count is printed at end of redefine_single_class()
4099 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4100 }
4101
4102 for (Klass *subk = ik->subklass(); subk != NULL;
4103 subk = subk->next_sibling()) {
4104 if (subk->is_instance_klass()) {
4105 // Only update instanceKlasses
4106 InstanceKlass *subik = InstanceKlass::cast(subk);
4107 // recursively do subclasses of the current subclass
4108 increment_class_counter(subik, THREAD);
4109 }
4110 }
4111 }
4112
4113 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4114 bool no_old_methods = true; // be optimistic
4115
4116 // Both array and instance classes have vtables.
4117 // a vtable should never contain old or obsolete methods
4118 ResourceMark rm(_thread);
4119 if (k->vtable_length() > 0 &&
4120 !k->vtable().check_no_old_or_obsolete_entries()) {
4121 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4122 log_trace(redefine, class, obsolete, metadata)
4123 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4124 k->signature_name());
4125 k->vtable().dump_vtable();
4126 }
4127 no_old_methods = false;
4128 }
4129
4130 if (k->is_instance_klass()) {
4131 HandleMark hm(_thread);
4132 InstanceKlass *ik = InstanceKlass::cast(k);
4133
4134 // an itable should never contain old or obsolete methods
4135 if (ik->itable_length() > 0 &&
4136 !ik->itable().check_no_old_or_obsolete_entries()) {
4137 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4138 log_trace(redefine, class, obsolete, metadata)
4139 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4140 ik->signature_name());
4141 ik->itable().dump_itable();
4142 }
4143 no_old_methods = false;
4144 }
4145
4146 // the constant pool cache should never contain non-deleted old or obsolete methods
4147 if (ik->constants() != NULL &&
4148 ik->constants()->cache() != NULL &&
4149 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4150 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4151 log_trace(redefine, class, obsolete, metadata)
4152 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4153 ik->signature_name());
4154 ik->constants()->cache()->dump_cache();
4155 }
4156 no_old_methods = false;
4157 }
4158 }
4159
4160 // print and fail guarantee if old methods are found.
4161 if (!no_old_methods) {
4162 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4163 dump_methods();
4164 } else {
4165 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4166 "to see more info about the following guarantee() failure.");
4167 }
4168 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4169 }
4170 }
4171
4172
4173 void VM_RedefineClasses::dump_methods() {
4174 int j;
4175 log_trace(redefine, class, dump)("_old_methods --");
4176 for (j = 0; j < _old_methods->length(); ++j) {
4177 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4178 Method* m = _old_methods->at(j);
4179 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4180 m->access_flags().print_on(&log_stream);
4181 log_stream.print(" -- ");
4182 m->print_name(&log_stream);
4183 log_stream.cr();
4184 }
4185 log_trace(redefine, class, dump)("_new_methods --");
4186 for (j = 0; j < _new_methods->length(); ++j) {
4187 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4188 Method* m = _new_methods->at(j);
4189 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4190 m->access_flags().print_on(&log_stream);
4191 log_stream.print(" -- ");
4192 m->print_name(&log_stream);
4193 log_stream.cr();
4194 }
4195 log_trace(redefine, class, dump)("_matching_methods --");
4196 for (j = 0; j < _matching_methods_length; ++j) {
4197 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4198 Method* m = _matching_old_methods[j];
4199 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4200 m->access_flags().print_on(&log_stream);
4201 log_stream.print(" -- ");
4202 m->print_name();
4203 log_stream.cr();
4204
4205 m = _matching_new_methods[j];
4206 log_stream.print(" (%5d) ", m->vtable_index());
4207 m->access_flags().print_on(&log_stream);
4208 log_stream.cr();
4209 }
4210 log_trace(redefine, class, dump)("_deleted_methods --");
4211 for (j = 0; j < _deleted_methods_length; ++j) {
4212 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4213 Method* m = _deleted_methods[j];
4214 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4215 m->access_flags().print_on(&log_stream);
4216 log_stream.print(" -- ");
4217 m->print_name(&log_stream);
4218 log_stream.cr();
4219 }
4220 log_trace(redefine, class, dump)("_added_methods --");
4221 for (j = 0; j < _added_methods_length; ++j) {
4222 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4223 Method* m = _added_methods[j];
4224 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4225 m->access_flags().print_on(&log_stream);
4226 log_stream.print(" -- ");
4227 m->print_name(&log_stream);
4228 log_stream.cr();
4229 }
4230 }
4231
4232 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4233 VM_Operation::print_on_error(st);
4234 if (_the_class != NULL) {
4235 ResourceMark rm;
4236 st->print_cr(", redefining class %s", _the_class->external_name());
4237 }
4238 }