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