1 /*
2 * Copyright (c) 2003, 2020, 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/classLoaderDataGraph.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/metadataOnStackMark.hpp"
31 #include "classfile/symbolTable.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/verifier.hpp"
34 #include "code/codeCache.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "interpreter/oopMapCache.hpp"
37 #include "interpreter/rewriter.hpp"
38 #include "jfr/jfrEvents.hpp"
39 #include "logging/logStream.hpp"
40 #include "memory/metadataFactory.hpp"
41 #include "memory/metaspaceShared.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/annotations.hpp"
45 #include "oops/constantPool.hpp"
46 #include "oops/fieldStreams.inline.hpp"
47 #include "oops/klassVtable.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/recordComponent.hpp"
50 #include "prims/jvmtiImpl.hpp"
51 #include "prims/jvmtiRedefineClasses.hpp"
52 #include "prims/jvmtiThreadState.inline.hpp"
53 #include "prims/resolvedMethodTable.hpp"
54 #include "prims/methodComparator.hpp"
55 #include "runtime/atomic.hpp"
56 #include "runtime/deoptimization.hpp"
57 #include "runtime/handles.inline.hpp"
58 #include "runtime/jniHandles.inline.hpp"
59 #include "runtime/relocator.hpp"
60 #include "runtime/safepointVerifiers.hpp"
61 #include "utilities/bitMap.inline.hpp"
62 #include "utilities/events.hpp"
63
64 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
65 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
66 Method** VM_RedefineClasses::_matching_old_methods = NULL;
67 Method** VM_RedefineClasses::_matching_new_methods = NULL;
68 Method** VM_RedefineClasses::_deleted_methods = NULL;
69 Method** VM_RedefineClasses::_added_methods = NULL;
70 int VM_RedefineClasses::_matching_methods_length = 0;
71 int VM_RedefineClasses::_deleted_methods_length = 0;
72 int VM_RedefineClasses::_added_methods_length = 0;
73 bool VM_RedefineClasses::_has_redefined_Object = false;
74 bool VM_RedefineClasses::_has_null_class_loader = false;
75 u8 VM_RedefineClasses::_id_counter = 0;
76
77 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
78 const jvmtiClassDefinition *class_defs,
79 JvmtiClassLoadKind class_load_kind) {
80 _class_count = class_count;
81 _class_defs = class_defs;
82 _class_load_kind = class_load_kind;
83 _any_class_has_resolved_methods = false;
84 _res = JVMTI_ERROR_NONE;
85 _the_class = NULL;
86 _has_redefined_Object = false;
87 _has_null_class_loader = false;
88 _id = next_id();
89 }
90
91 static inline InstanceKlass* get_ik(jclass def) {
92 oop mirror = JNIHandles::resolve_non_null(def);
93 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
94 }
95
96 // If any of the classes are being redefined, wait
97 // Parallel constant pool merging leads to indeterminate constant pools.
98 void VM_RedefineClasses::lock_classes() {
99 MonitorLocker ml(RedefineClasses_lock);
100 bool has_redefined;
101 do {
102 has_redefined = false;
103 // Go through classes each time until none are being redefined.
104 for (int i = 0; i < _class_count; i++) {
105 if (get_ik(_class_defs[i].klass)->is_being_redefined()) {
106 ml.wait();
107 has_redefined = true;
108 break; // for loop
109 }
110 }
111 } while (has_redefined);
112 for (int i = 0; i < _class_count; i++) {
113 get_ik(_class_defs[i].klass)->set_is_being_redefined(true);
114 }
115 ml.notify_all();
116 }
117
118 void VM_RedefineClasses::unlock_classes() {
119 MonitorLocker ml(RedefineClasses_lock);
120 for (int i = 0; i < _class_count; i++) {
121 assert(get_ik(_class_defs[i].klass)->is_being_redefined(),
122 "should be being redefined to get here");
123 get_ik(_class_defs[i].klass)->set_is_being_redefined(false);
124 }
125 ml.notify_all();
126 }
127
128 bool VM_RedefineClasses::doit_prologue() {
129 if (_class_count == 0) {
130 _res = JVMTI_ERROR_NONE;
131 return false;
132 }
133 if (_class_defs == NULL) {
134 _res = JVMTI_ERROR_NULL_POINTER;
135 return false;
136 }
137
138 for (int i = 0; i < _class_count; i++) {
139 if (_class_defs[i].klass == NULL) {
140 _res = JVMTI_ERROR_INVALID_CLASS;
141 return false;
142 }
143 if (_class_defs[i].class_byte_count == 0) {
144 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
145 return false;
146 }
147 if (_class_defs[i].class_bytes == NULL) {
148 _res = JVMTI_ERROR_NULL_POINTER;
149 return false;
150 }
151
152 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
153 // classes for primitives, arrays, hidden and vm unsafe anonymous classes
154 // cannot be redefined. Check here so following code can assume these classes
155 // are InstanceKlass.
156 if (!is_modifiable_class(mirror)) {
157 _res = JVMTI_ERROR_UNMODIFIABLE_CLASS;
158 return false;
159 }
160 }
161
162 // Start timer after all the sanity checks; not quite accurate, but
163 // better than adding a bunch of stop() calls.
164 if (log_is_enabled(Info, redefine, class, timer)) {
165 _timer_vm_op_prologue.start();
166 }
167
168 lock_classes();
169 // We first load new class versions in the prologue, because somewhere down the
170 // call chain it is required that the current thread is a Java thread.
171 _res = load_new_class_versions(Thread::current());
172 if (_res != JVMTI_ERROR_NONE) {
173 // free any successfully created classes, since none are redefined
174 for (int i = 0; i < _class_count; i++) {
175 if (_scratch_classes[i] != NULL) {
176 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
177 // Free the memory for this class at class unloading time. Not before
178 // because CMS might think this is still live.
179 InstanceKlass* ik = get_ik(_class_defs[i].klass);
180 if (ik->get_cached_class_file() == _scratch_classes[i]->get_cached_class_file()) {
181 // Don't double-free cached_class_file copied from the original class if error.
182 _scratch_classes[i]->set_cached_class_file(NULL);
183 }
184 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
185 }
186 }
187 // Free os::malloc allocated memory in load_new_class_version.
188 os::free(_scratch_classes);
189 _timer_vm_op_prologue.stop();
190 unlock_classes();
191 return false;
192 }
193
194 _timer_vm_op_prologue.stop();
195 return true;
196 }
197
198 void VM_RedefineClasses::doit() {
199 Thread *thread = Thread::current();
200
201 #if INCLUDE_CDS
202 if (UseSharedSpaces) {
203 // Sharing is enabled so we remap the shared readonly space to
204 // shared readwrite, private just in case we need to redefine
205 // a shared class. We do the remap during the doit() phase of
206 // the safepoint to be safer.
207 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
208 log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private");
209 _res = JVMTI_ERROR_INTERNAL;
210 return;
211 }
212 }
213 #endif
214
215 // Mark methods seen on stack and everywhere else so old methods are not
216 // cleaned up if they're on the stack.
217 MetadataOnStackMark md_on_stack(/*walk_all_metadata*/true, /*redefinition_walk*/true);
218 HandleMark hm(thread); // make sure any handles created are deleted
219 // before the stack walk again.
220
221 for (int i = 0; i < _class_count; i++) {
222 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
223 }
224
225 // Flush all compiled code that depends on the classes redefined.
226 flush_dependent_code();
227
228 // Adjust constantpool caches and vtables for all classes
229 // that reference methods of the evolved classes.
230 // Have to do this after all classes are redefined and all methods that
231 // are redefined are marked as old.
232 AdjustAndCleanMetadata adjust_and_clean_metadata(thread);
233 ClassLoaderDataGraph::classes_do(&adjust_and_clean_metadata);
234
235 // JSR-292 support
236 if (_any_class_has_resolved_methods) {
237 bool trace_name_printed = false;
238 ResolvedMethodTable::adjust_method_entries(&trace_name_printed);
239 }
240
241 // Increment flag indicating that some invariants are no longer true.
242 // See jvmtiExport.hpp for detailed explanation.
243 JvmtiExport::increment_redefinition_count();
244
245 // check_class() is optionally called for product bits, but is
246 // always called for non-product bits.
247 #ifdef PRODUCT
248 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
249 #endif
250 log_trace(redefine, class, obsolete, metadata)("calling check_class");
251 CheckClass check_class(thread);
252 ClassLoaderDataGraph::classes_do(&check_class);
253 #ifdef PRODUCT
254 }
255 #endif
256
257 // Clean up any metadata now unreferenced while MetadataOnStackMark is set.
258 ClassLoaderDataGraph::clean_deallocate_lists(false);
259 }
260
261 void VM_RedefineClasses::doit_epilogue() {
262 unlock_classes();
263
264 // Free os::malloc allocated memory.
265 os::free(_scratch_classes);
266
267 // Reset the_class to null for error printing.
268 _the_class = NULL;
269
270 if (log_is_enabled(Info, redefine, class, timer)) {
271 // Used to have separate timers for "doit" and "all", but the timer
272 // overhead skewed the measurements.
273 julong doit_time = _timer_rsc_phase1.milliseconds() +
274 _timer_rsc_phase2.milliseconds();
275 julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
276
277 log_info(redefine, class, timer)
278 ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT,
279 all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time);
280 log_info(redefine, class, timer)
281 ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT,
282 (julong)_timer_rsc_phase1.milliseconds(), (julong)_timer_rsc_phase2.milliseconds());
283 }
284 }
285
286 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
287 // classes for primitives cannot be redefined
288 if (java_lang_Class::is_primitive(klass_mirror)) {
289 return false;
290 }
291 Klass* k = java_lang_Class::as_Klass(klass_mirror);
292 // classes for arrays cannot be redefined
293 if (k == NULL || !k->is_instance_klass()) {
294 return false;
295 }
296
297 // Cannot redefine or retransform a hidden or an unsafe anonymous class.
298 if (InstanceKlass::cast(k)->is_hidden() ||
299 InstanceKlass::cast(k)->is_unsafe_anonymous()) {
300 return false;
301 }
302 return true;
303 }
304
305 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
306 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
307 // direct CP entries, there is just the current entry to append. For
308 // indirect and double-indirect CP entries, there are zero or more
309 // referenced CP entries along with the current entry to append.
310 // Indirect and double-indirect CP entries are handled by recursive
311 // calls to append_entry() as needed. The referenced CP entries are
312 // always appended to *merge_cp_p before the referee CP entry. These
313 // referenced CP entries may already exist in *merge_cp_p in which case
314 // there is nothing extra to append and only the current entry is
315 // appended.
316 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
317 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
318 TRAPS) {
319
320 // append is different depending on entry tag type
321 switch (scratch_cp->tag_at(scratch_i).value()) {
322
323 // The old verifier is implemented outside the VM. It loads classes,
324 // but does not resolve constant pool entries directly so we never
325 // see Class entries here with the old verifier. Similarly the old
326 // verifier does not like Class entries in the input constant pool.
327 // The split-verifier is implemented in the VM so it can optionally
328 // and directly resolve constant pool entries to load classes. The
329 // split-verifier can accept either Class entries or UnresolvedClass
330 // entries in the input constant pool. We revert the appended copy
331 // back to UnresolvedClass so that either verifier will be happy
332 // with the constant pool entry.
333 //
334 // this is an indirect CP entry so it needs special handling
335 case JVM_CONSTANT_Class:
336 case JVM_CONSTANT_UnresolvedClass:
337 {
338 int name_i = scratch_cp->klass_name_index_at(scratch_i);
339 int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p,
340 merge_cp_length_p, THREAD);
341
342 if (new_name_i != name_i) {
343 log_trace(redefine, class, constantpool)
344 ("Class entry@%d name_index change: %d to %d",
345 *merge_cp_length_p, name_i, new_name_i);
346 }
347
348 (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_i);
349 if (scratch_i != *merge_cp_length_p) {
350 // The new entry in *merge_cp_p is at a different index than
351 // the new entry in scratch_cp so we need to map the index values.
352 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
353 }
354 (*merge_cp_length_p)++;
355 } break;
356
357 // these are direct CP entries so they can be directly appended,
358 // but double and long take two constant pool entries
359 case JVM_CONSTANT_Double: // fall through
360 case JVM_CONSTANT_Long:
361 {
362 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
363 THREAD);
364
365 if (scratch_i != *merge_cp_length_p) {
366 // The new entry in *merge_cp_p is at a different index than
367 // the new entry in scratch_cp so we need to map the index values.
368 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
369 }
370 (*merge_cp_length_p) += 2;
371 } break;
372
373 // these are direct CP entries so they can be directly appended
374 case JVM_CONSTANT_Float: // fall through
375 case JVM_CONSTANT_Integer: // fall through
376 case JVM_CONSTANT_Utf8: // fall through
377
378 // This was an indirect CP entry, but it has been changed into
379 // Symbol*s so this entry can be directly appended.
380 case JVM_CONSTANT_String: // fall through
381 {
382 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
383 THREAD);
384
385 if (scratch_i != *merge_cp_length_p) {
386 // The new entry in *merge_cp_p is at a different index than
387 // the new entry in scratch_cp so we need to map the index values.
388 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
389 }
390 (*merge_cp_length_p)++;
391 } break;
392
393 // this is an indirect CP entry so it needs special handling
394 case JVM_CONSTANT_NameAndType:
395 {
396 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
397 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
398 merge_cp_length_p, THREAD);
399
400 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
401 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
402 merge_cp_p, merge_cp_length_p,
403 THREAD);
404
405 // If the referenced entries already exist in *merge_cp_p, then
406 // both new_name_ref_i and new_signature_ref_i will both be 0.
407 // In that case, all we are appending is the current entry.
408 if (new_name_ref_i != name_ref_i) {
409 log_trace(redefine, class, constantpool)
410 ("NameAndType entry@%d name_ref_index change: %d to %d",
411 *merge_cp_length_p, name_ref_i, new_name_ref_i);
412 }
413 if (new_signature_ref_i != signature_ref_i) {
414 log_trace(redefine, class, constantpool)
415 ("NameAndType entry@%d signature_ref_index change: %d to %d",
416 *merge_cp_length_p, signature_ref_i, new_signature_ref_i);
417 }
418
419 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
420 new_name_ref_i, new_signature_ref_i);
421 if (scratch_i != *merge_cp_length_p) {
422 // The new entry in *merge_cp_p is at a different index than
423 // the new entry in scratch_cp so we need to map the index values.
424 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
425 }
426 (*merge_cp_length_p)++;
427 } break;
428
429 // this is a double-indirect CP entry so it needs special handling
430 case JVM_CONSTANT_Fieldref: // fall through
431 case JVM_CONSTANT_InterfaceMethodref: // fall through
432 case JVM_CONSTANT_Methodref:
433 {
434 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
435 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
436 merge_cp_p, merge_cp_length_p, THREAD);
437
438 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
439 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
440 merge_cp_p, merge_cp_length_p, THREAD);
441
442 const char *entry_name = NULL;
443 switch (scratch_cp->tag_at(scratch_i).value()) {
444 case JVM_CONSTANT_Fieldref:
445 entry_name = "Fieldref";
446 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
447 new_name_and_type_ref_i);
448 break;
449 case JVM_CONSTANT_InterfaceMethodref:
450 entry_name = "IFMethodref";
451 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
452 new_klass_ref_i, new_name_and_type_ref_i);
453 break;
454 case JVM_CONSTANT_Methodref:
455 entry_name = "Methodref";
456 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
457 new_name_and_type_ref_i);
458 break;
459 default:
460 guarantee(false, "bad switch");
461 break;
462 }
463
464 if (klass_ref_i != new_klass_ref_i) {
465 log_trace(redefine, class, constantpool)
466 ("%s entry@%d class_index changed: %d to %d", entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i);
467 }
468 if (name_and_type_ref_i != new_name_and_type_ref_i) {
469 log_trace(redefine, class, constantpool)
470 ("%s entry@%d name_and_type_index changed: %d to %d",
471 entry_name, *merge_cp_length_p, name_and_type_ref_i, new_name_and_type_ref_i);
472 }
473
474 if (scratch_i != *merge_cp_length_p) {
475 // The new entry in *merge_cp_p is at a different index than
476 // the new entry in scratch_cp so we need to map the index values.
477 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
478 }
479 (*merge_cp_length_p)++;
480 } break;
481
482 // this is an indirect CP entry so it needs special handling
483 case JVM_CONSTANT_MethodType:
484 {
485 int ref_i = scratch_cp->method_type_index_at(scratch_i);
486 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
487 merge_cp_length_p, THREAD);
488 if (new_ref_i != ref_i) {
489 log_trace(redefine, class, constantpool)
490 ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
491 }
492 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
493 if (scratch_i != *merge_cp_length_p) {
494 // The new entry in *merge_cp_p is at a different index than
495 // the new entry in scratch_cp so we need to map the index values.
496 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
497 }
498 (*merge_cp_length_p)++;
499 } break;
500
501 // this is an indirect CP entry so it needs special handling
502 case JVM_CONSTANT_MethodHandle:
503 {
504 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
505 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
506 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
507 merge_cp_length_p, THREAD);
508 if (new_ref_i != ref_i) {
509 log_trace(redefine, class, constantpool)
510 ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i);
511 }
512 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, 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 // this is an indirect CP entry so it needs special handling
522 case JVM_CONSTANT_Dynamic: // fall through
523 case JVM_CONSTANT_InvokeDynamic:
524 {
525 // Index of the bootstrap specifier in the operands array
526 int old_bs_i = scratch_cp->bootstrap_methods_attribute_index(scratch_i);
527 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
528 merge_cp_length_p, THREAD);
529 // The bootstrap method NameAndType_info index
530 int old_ref_i = scratch_cp->bootstrap_name_and_type_ref_index_at(scratch_i);
531 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
532 merge_cp_length_p, THREAD);
533 if (new_bs_i != old_bs_i) {
534 log_trace(redefine, class, constantpool)
535 ("Dynamic entry@%d bootstrap_method_attr_index change: %d to %d",
536 *merge_cp_length_p, old_bs_i, new_bs_i);
537 }
538 if (new_ref_i != old_ref_i) {
539 log_trace(redefine, class, constantpool)
540 ("Dynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i);
541 }
542
543 if (scratch_cp->tag_at(scratch_i).is_dynamic_constant())
544 (*merge_cp_p)->dynamic_constant_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
545 else
546 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
547 if (scratch_i != *merge_cp_length_p) {
548 // The new entry in *merge_cp_p is at a different index than
549 // the new entry in scratch_cp so we need to map the index values.
550 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
551 }
552 (*merge_cp_length_p)++;
553 } break;
554
555 // At this stage, Class or UnresolvedClass could be in scratch_cp, but not
556 // ClassIndex
557 case JVM_CONSTANT_ClassIndex: // fall through
558
559 // Invalid is used as the tag for the second constant pool entry
560 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
561 // not be seen by itself.
562 case JVM_CONSTANT_Invalid: // fall through
563
564 // At this stage, String could be here, but not StringIndex
565 case JVM_CONSTANT_StringIndex: // fall through
566
567 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
568 // here
569 case JVM_CONSTANT_UnresolvedClassInError: // fall through
570
571 default:
572 {
573 // leave a breadcrumb
574 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
575 ShouldNotReachHere();
576 } break;
577 } // end switch tag value
578 } // end append_entry()
579
580
581 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
582 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
583
584 int new_ref_i = ref_i;
585 bool match = (ref_i < *merge_cp_length_p) &&
586 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
587
588 if (!match) {
589 // forward reference in *merge_cp_p or not a direct match
590 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
591 if (found_i != 0) {
592 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
593 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
594 new_ref_i = found_i;
595 map_index(scratch_cp, ref_i, found_i);
596 } else {
597 // no match found so we have to append this entry to *merge_cp_p
598 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
599 // The above call to append_entry() can only append one entry
600 // so the post call query of *merge_cp_length_p is only for
601 // the sake of consistency.
602 new_ref_i = *merge_cp_length_p - 1;
603 }
604 }
605
606 return new_ref_i;
607 } // end find_or_append_indirect_entry()
608
609
610 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
611 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
612 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
613 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
614 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
615
616 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
617 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
618 merge_cp_length_p, THREAD);
619 if (new_ref_i != old_ref_i) {
620 log_trace(redefine, class, constantpool)
621 ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i);
622 }
623
624 Array<u2>* merge_ops = (*merge_cp_p)->operands();
625 int new_bs_i = _operands_cur_length;
626 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
627 // However, the operand_offset_at(0) was set in the extend_operands() call.
628 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
629 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
630 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
631
632 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
633 merge_ops->at_put(new_base++, new_ref_i);
634 merge_ops->at_put(new_base++, argc);
635
636 for (int i = 0; i < argc; i++) {
637 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
638 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
639 merge_cp_length_p, THREAD);
640 merge_ops->at_put(new_base++, new_arg_ref_i);
641 if (new_arg_ref_i != old_arg_ref_i) {
642 log_trace(redefine, class, constantpool)
643 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
644 _operands_cur_length, old_arg_ref_i, new_arg_ref_i);
645 }
646 }
647 if (old_bs_i != _operands_cur_length) {
648 // The bootstrap specifier in *merge_cp_p is at a different index than
649 // that in scratch_cp so we need to map the index values.
650 map_operand_index(old_bs_i, new_bs_i);
651 }
652 _operands_cur_length++;
653 } // end append_operand()
654
655
656 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
657 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
658
659 int new_bs_i = old_bs_i; // bootstrap specifier index
660 bool match = (old_bs_i < _operands_cur_length) &&
661 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
662
663 if (!match) {
664 // forward reference in *merge_cp_p or not a direct match
665 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
666 _operands_cur_length, THREAD);
667 if (found_i != -1) {
668 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
669 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
670 new_bs_i = found_i;
671 map_operand_index(old_bs_i, found_i);
672 } else {
673 // no match found so we have to append this bootstrap specifier to *merge_cp_p
674 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
675 new_bs_i = _operands_cur_length - 1;
676 }
677 }
678 return new_bs_i;
679 } // end find_or_append_operand()
680
681
682 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
683 if (merge_cp->operands() == NULL) {
684 return;
685 }
686 // Shrink the merge_cp operands
687 merge_cp->shrink_operands(_operands_cur_length, CHECK);
688
689 if (log_is_enabled(Trace, redefine, class, constantpool)) {
690 // don't want to loop unless we are tracing
691 int count = 0;
692 for (int i = 1; i < _operands_index_map_p->length(); i++) {
693 int value = _operands_index_map_p->at(i);
694 if (value != -1) {
695 log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value);
696 count++;
697 }
698 }
699 }
700 // Clean-up
701 _operands_index_map_p = NULL;
702 _operands_cur_length = 0;
703 _operands_index_map_count = 0;
704 } // end finalize_operands_merge()
705
706 // Symbol* comparator for qsort
707 // The caller must have an active ResourceMark.
708 static int symcmp(const void* a, const void* b) {
709 char* astr = (*(Symbol**)a)->as_C_string();
710 char* bstr = (*(Symbol**)b)->as_C_string();
711 return strcmp(astr, bstr);
712 }
713
714 static jvmtiError check_nest_attributes(InstanceKlass* the_class,
715 InstanceKlass* scratch_class) {
716 // Check whether the class NestHost attribute has been changed.
717 Thread* thread = Thread::current();
718 ResourceMark rm(thread);
719 u2 the_nest_host_idx = the_class->nest_host_index();
720 u2 scr_nest_host_idx = scratch_class->nest_host_index();
721
722 if (the_nest_host_idx != 0 && scr_nest_host_idx != 0) {
723 Symbol* the_sym = the_class->constants()->klass_name_at(the_nest_host_idx);
724 Symbol* scr_sym = scratch_class->constants()->klass_name_at(scr_nest_host_idx);
725 if (the_sym != scr_sym) {
726 log_trace(redefine, class, nestmates)
727 ("redefined class %s attribute change error: NestHost class: %s replaced with: %s",
728 the_class->external_name(), the_sym->as_C_string(), scr_sym->as_C_string());
729 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
730 }
731 } else if ((the_nest_host_idx == 0) ^ (scr_nest_host_idx == 0)) {
732 const char* action_str = (the_nest_host_idx != 0) ? "removed" : "added";
733 log_trace(redefine, class, nestmates)
734 ("redefined class %s attribute change error: NestHost attribute %s",
735 the_class->external_name(), action_str);
736 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
737 }
738
739 // Check whether the class NestMembers attribute has been changed.
740 Array<u2>* the_nest_members = the_class->nest_members();
741 Array<u2>* scr_nest_members = scratch_class->nest_members();
742 bool the_members_exists = the_nest_members != Universe::the_empty_short_array();
743 bool scr_members_exists = scr_nest_members != Universe::the_empty_short_array();
744
745 int members_len = the_nest_members->length();
746 if (the_members_exists && scr_members_exists) {
747 if (members_len != scr_nest_members->length()) {
748 log_trace(redefine, class, nestmates)
749 ("redefined class %s attribute change error: NestMember len=%d changed to len=%d",
750 the_class->external_name(), members_len, scr_nest_members->length());
751 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
752 }
753
754 // The order of entries in the NestMembers array is not specified so we
755 // have to explicitly check for the same contents. We do this by copying
756 // the referenced symbols into their own arrays, sorting them and then
757 // comparing each element pair.
758
759 Symbol** the_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, members_len);
760 Symbol** scr_syms = NEW_RESOURCE_ARRAY_RETURN_NULL(Symbol*, members_len);
761
762 if (the_syms == NULL || scr_syms == NULL) {
763 return JVMTI_ERROR_OUT_OF_MEMORY;
764 }
765
766 for (int i = 0; i < members_len; i++) {
767 int the_cp_index = the_nest_members->at(i);
768 int scr_cp_index = scr_nest_members->at(i);
769 the_syms[i] = the_class->constants()->klass_name_at(the_cp_index);
770 scr_syms[i] = scratch_class->constants()->klass_name_at(scr_cp_index);
771 }
772
773 qsort(the_syms, members_len, sizeof(Symbol*), symcmp);
774 qsort(scr_syms, members_len, sizeof(Symbol*), symcmp);
775
776 for (int i = 0; i < members_len; i++) {
777 if (the_syms[i] != scr_syms[i]) {
778 log_trace(redefine, class, nestmates)
779 ("redefined class %s attribute change error: NestMembers[%d]: %s changed to %s",
780 the_class->external_name(), i, the_syms[i]->as_C_string(), scr_syms[i]->as_C_string());
781 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
782 }
783 }
784 } else if (the_members_exists ^ scr_members_exists) {
785 const char* action_str = (the_members_exists) ? "removed" : "added";
786 log_trace(redefine, class, nestmates)
787 ("redefined class %s attribute change error: NestMembers attribute %s",
788 the_class->external_name(), action_str);
789 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
790 }
791
792 return JVMTI_ERROR_NONE;
793 }
794
795 // Return an error status if the class Record attribute was changed.
796 static jvmtiError check_record_attribute(InstanceKlass* the_class, InstanceKlass* scratch_class) {
797 // Get lists of record components.
798 Array<RecordComponent*>* the_record = the_class->record_components();
799 Array<RecordComponent*>* scr_record = scratch_class->record_components();
800 bool the_record_exists = the_record != NULL;
801 bool scr_record_exists = scr_record != NULL;
802
803 if (the_record_exists && scr_record_exists) {
804 int the_num_components = the_record->length();
805 int scr_num_components = scr_record->length();
806 if (the_num_components != scr_num_components) {
807 log_trace(redefine, class, record)
808 ("redefined class %s attribute change error: Record num_components=%d changed to num_components=%d",
809 the_class->external_name(), the_num_components, scr_num_components);
810 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
811 }
812
813 // Compare each field in each record component.
814 ConstantPool* the_cp = the_class->constants();
815 ConstantPool* scr_cp = scratch_class->constants();
816 for (int x = 0; x < the_num_components; x++) {
817 RecordComponent* the_component = the_record->at(x);
818 RecordComponent* scr_component = scr_record->at(x);
819 const Symbol* const the_name = the_cp->symbol_at(the_component->name_index());
820 const Symbol* const scr_name = scr_cp->symbol_at(scr_component->name_index());
821 const Symbol* const the_descr = the_cp->symbol_at(the_component->descriptor_index());
822 const Symbol* const scr_descr = scr_cp->symbol_at(scr_component->descriptor_index());
823 if (the_name != scr_name || the_descr != scr_descr) {
824 log_trace(redefine, class, record)
825 ("redefined class %s attribute change error: Record name_index, descriptor_index, and/or attributes_count changed",
826 the_class->external_name());
827 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
828 }
829
830 int the_gen_sig = the_component->generic_signature_index();
831 int scr_gen_sig = scr_component->generic_signature_index();
832 const Symbol* const the_gen_sig_sym = (the_gen_sig == 0 ? NULL :
833 the_cp->symbol_at(the_component->generic_signature_index()));
834 const Symbol* const scr_gen_sig_sym = (scr_gen_sig == 0 ? NULL :
835 scr_cp->symbol_at(scr_component->generic_signature_index()));
836 if (the_gen_sig_sym != scr_gen_sig_sym) {
837 log_trace(redefine, class, record)
838 ("redefined class %s attribute change error: Record generic_signature attribute changed",
839 the_class->external_name());
840 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
841 }
842
843 // It's okay if a record component's annotations were changed.
844 }
845
846 } else if (the_record_exists ^ scr_record_exists) {
847 const char* action_str = (the_record_exists) ? "removed" : "added";
848 log_trace(redefine, class, record)
849 ("redefined class %s attribute change error: Record attribute %s",
850 the_class->external_name(), action_str);
851 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED;
852 }
853
854 return JVMTI_ERROR_NONE;
855 }
856
857
858 static bool can_add_or_delete(Method* m) {
859 // Compatibility mode
860 return (AllowRedefinitionToAddDeleteMethods &&
861 (m->is_private() && (m->is_static() || m->is_final())));
862 }
863
864 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
865 InstanceKlass* the_class,
866 InstanceKlass* scratch_class) {
867 int i;
868
869 // Check superclasses, or rather their names, since superclasses themselves can be
870 // requested to replace.
871 // Check for NULL superclass first since this might be java.lang.Object
872 if (the_class->super() != scratch_class->super() &&
873 (the_class->super() == NULL || scratch_class->super() == NULL ||
874 the_class->super()->name() !=
875 scratch_class->super()->name())) {
876 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
877 }
878
879 // Check if the number, names and order of directly implemented interfaces are the same.
880 // I think in principle we should just check if the sets of names of directly implemented
881 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
882 // .java file, also changes in .class file) should not matter. However, comparing sets is
883 // technically a bit more difficult, and, more importantly, I am not sure at present that the
884 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
885 // rely on it somewhere.
886 Array<InstanceKlass*>* k_interfaces = the_class->local_interfaces();
887 Array<InstanceKlass*>* k_new_interfaces = scratch_class->local_interfaces();
888 int n_intfs = k_interfaces->length();
889 if (n_intfs != k_new_interfaces->length()) {
890 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
891 }
892 for (i = 0; i < n_intfs; i++) {
893 if (k_interfaces->at(i)->name() !=
894 k_new_interfaces->at(i)->name()) {
895 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
896 }
897 }
898
899 // Check whether class is in the error init state.
900 if (the_class->is_in_error_state()) {
901 // TBD #5057930: special error code is needed in 1.6
902 return JVMTI_ERROR_INVALID_CLASS;
903 }
904
905 // Check whether the nest-related attributes have been changed.
906 jvmtiError err = check_nest_attributes(the_class, scratch_class);
907 if (err != JVMTI_ERROR_NONE) {
908 return err;
909 }
910
911 // Check whether the Record attribute has been changed.
912 err = check_record_attribute(the_class, scratch_class);
913 if (err != JVMTI_ERROR_NONE) {
914 return err;
915 }
916
917 // Check whether class modifiers are the same.
918 jushort old_flags = (jushort) the_class->access_flags().get_flags();
919 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
920 if (old_flags != new_flags) {
921 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
922 }
923
924 // Check if the number, names, types and order of fields declared in these classes
925 // are the same.
926 JavaFieldStream old_fs(the_class);
927 JavaFieldStream new_fs(scratch_class);
928 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
929 // access
930 old_flags = old_fs.access_flags().as_short();
931 new_flags = new_fs.access_flags().as_short();
932 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
933 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
934 }
935 // offset
936 if (old_fs.offset() != new_fs.offset()) {
937 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
938 }
939 // name and signature
940 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
941 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
942 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
943 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
944 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
945 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
946 }
947 }
948
949 // If both streams aren't done then we have a differing number of
950 // fields.
951 if (!old_fs.done() || !new_fs.done()) {
952 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
953 }
954
955 // Do a parallel walk through the old and new methods. Detect
956 // cases where they match (exist in both), have been added in
957 // the new methods, or have been deleted (exist only in the
958 // old methods). The class file parser places methods in order
959 // by method name, but does not order overloaded methods by
960 // signature. In order to determine what fate befell the methods,
961 // this code places the overloaded new methods that have matching
962 // old methods in the same order as the old methods and places
963 // new overloaded methods at the end of overloaded methods of
964 // that name. The code for this order normalization is adapted
965 // from the algorithm used in InstanceKlass::find_method().
966 // Since we are swapping out of order entries as we find them,
967 // we only have to search forward through the overloaded methods.
968 // Methods which are added and have the same name as an existing
969 // method (but different signature) will be put at the end of
970 // the methods with that name, and the name mismatch code will
971 // handle them.
972 Array<Method*>* k_old_methods(the_class->methods());
973 Array<Method*>* k_new_methods(scratch_class->methods());
974 int n_old_methods = k_old_methods->length();
975 int n_new_methods = k_new_methods->length();
976 Thread* thread = Thread::current();
977
978 int ni = 0;
979 int oi = 0;
980 while (true) {
981 Method* k_old_method;
982 Method* k_new_method;
983 enum { matched, added, deleted, undetermined } method_was = undetermined;
984
985 if (oi >= n_old_methods) {
986 if (ni >= n_new_methods) {
987 break; // we've looked at everything, done
988 }
989 // New method at the end
990 k_new_method = k_new_methods->at(ni);
991 method_was = added;
992 } else if (ni >= n_new_methods) {
993 // Old method, at the end, is deleted
994 k_old_method = k_old_methods->at(oi);
995 method_was = deleted;
996 } else {
997 // There are more methods in both the old and new lists
998 k_old_method = k_old_methods->at(oi);
999 k_new_method = k_new_methods->at(ni);
1000 if (k_old_method->name() != k_new_method->name()) {
1001 // Methods are sorted by method name, so a mismatch means added
1002 // or deleted
1003 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1004 method_was = added;
1005 } else {
1006 method_was = deleted;
1007 }
1008 } else if (k_old_method->signature() == k_new_method->signature()) {
1009 // Both the name and signature match
1010 method_was = matched;
1011 } else {
1012 // The name matches, but the signature doesn't, which means we have to
1013 // search forward through the new overloaded methods.
1014 int nj; // outside the loop for post-loop check
1015 for (nj = ni + 1; nj < n_new_methods; nj++) {
1016 Method* m = k_new_methods->at(nj);
1017 if (k_old_method->name() != m->name()) {
1018 // reached another method name so no more overloaded methods
1019 method_was = deleted;
1020 break;
1021 }
1022 if (k_old_method->signature() == m->signature()) {
1023 // found a match so swap the methods
1024 k_new_methods->at_put(ni, m);
1025 k_new_methods->at_put(nj, k_new_method);
1026 k_new_method = m;
1027 method_was = matched;
1028 break;
1029 }
1030 }
1031
1032 if (nj >= n_new_methods) {
1033 // reached the end without a match; so method was deleted
1034 method_was = deleted;
1035 }
1036 }
1037 }
1038
1039 switch (method_was) {
1040 case matched:
1041 // methods match, be sure modifiers do too
1042 old_flags = (jushort) k_old_method->access_flags().get_flags();
1043 new_flags = (jushort) k_new_method->access_flags().get_flags();
1044 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1045 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1046 }
1047 {
1048 u2 new_num = k_new_method->method_idnum();
1049 u2 old_num = k_old_method->method_idnum();
1050 if (new_num != old_num) {
1051 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1052 if (idnum_owner != NULL) {
1053 // There is already a method assigned this idnum -- switch them
1054 // Take current and original idnum from the new_method
1055 idnum_owner->set_method_idnum(new_num);
1056 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1057 }
1058 // Take current and original idnum from the old_method
1059 k_new_method->set_method_idnum(old_num);
1060 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
1061 if (thread->has_pending_exception()) {
1062 return JVMTI_ERROR_OUT_OF_MEMORY;
1063 }
1064 }
1065 }
1066 log_trace(redefine, class, normalize)
1067 ("Method matched: new: %s [%d] == old: %s [%d]",
1068 k_new_method->name_and_sig_as_C_string(), ni, k_old_method->name_and_sig_as_C_string(), oi);
1069 // advance to next pair of methods
1070 ++oi;
1071 ++ni;
1072 break;
1073 case added:
1074 // method added, see if it is OK
1075 if (!can_add_or_delete(k_new_method)) {
1076 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1077 }
1078 {
1079 u2 num = the_class->next_method_idnum();
1080 if (num == ConstMethod::UNSET_IDNUM) {
1081 // cannot add any more methods
1082 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1083 }
1084 u2 new_num = k_new_method->method_idnum();
1085 Method* idnum_owner = scratch_class->method_with_idnum(num);
1086 if (idnum_owner != NULL) {
1087 // There is already a method assigned this idnum -- switch them
1088 // Take current and original idnum from the new_method
1089 idnum_owner->set_method_idnum(new_num);
1090 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
1091 }
1092 k_new_method->set_method_idnum(num);
1093 k_new_method->set_orig_method_idnum(num);
1094 if (thread->has_pending_exception()) {
1095 return JVMTI_ERROR_OUT_OF_MEMORY;
1096 }
1097 }
1098 log_trace(redefine, class, normalize)
1099 ("Method added: new: %s [%d]", k_new_method->name_and_sig_as_C_string(), ni);
1100 ++ni; // advance to next new method
1101 break;
1102 case deleted:
1103 // method deleted, see if it is OK
1104 if (!can_add_or_delete(k_old_method)) {
1105 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1106 }
1107 log_trace(redefine, class, normalize)
1108 ("Method deleted: old: %s [%d]", k_old_method->name_and_sig_as_C_string(), oi);
1109 ++oi; // advance to next old method
1110 break;
1111 default:
1112 ShouldNotReachHere();
1113 }
1114 }
1115
1116 return JVMTI_ERROR_NONE;
1117 }
1118
1119
1120 // Find new constant pool index value for old constant pool index value
1121 // by seaching the index map. Returns zero (0) if there is no mapped
1122 // value for the old constant pool index.
1123 int VM_RedefineClasses::find_new_index(int old_index) {
1124 if (_index_map_count == 0) {
1125 // map is empty so nothing can be found
1126 return 0;
1127 }
1128
1129 if (old_index < 1 || old_index >= _index_map_p->length()) {
1130 // The old_index is out of range so it is not mapped. This should
1131 // not happen in regular constant pool merging use, but it can
1132 // happen if a corrupt annotation is processed.
1133 return 0;
1134 }
1135
1136 int value = _index_map_p->at(old_index);
1137 if (value == -1) {
1138 // the old_index is not mapped
1139 return 0;
1140 }
1141
1142 return value;
1143 } // end find_new_index()
1144
1145
1146 // Find new bootstrap specifier index value for old bootstrap specifier index
1147 // value by seaching the index map. Returns unused index (-1) if there is
1148 // no mapped value for the old bootstrap specifier index.
1149 int VM_RedefineClasses::find_new_operand_index(int old_index) {
1150 if (_operands_index_map_count == 0) {
1151 // map is empty so nothing can be found
1152 return -1;
1153 }
1154
1155 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1156 // The old_index is out of range so it is not mapped.
1157 // This should not happen in regular constant pool merging use.
1158 return -1;
1159 }
1160
1161 int value = _operands_index_map_p->at(old_index);
1162 if (value == -1) {
1163 // the old_index is not mapped
1164 return -1;
1165 }
1166
1167 return value;
1168 } // end find_new_operand_index()
1169
1170
1171 // Returns true if the current mismatch is due to a resolved/unresolved
1172 // class pair. Otherwise, returns false.
1173 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
1174 int index1, const constantPoolHandle& cp2, int index2) {
1175
1176 jbyte t1 = cp1->tag_at(index1).value();
1177 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
1178 return false; // wrong entry type; not our special case
1179 }
1180
1181 jbyte t2 = cp2->tag_at(index2).value();
1182 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1183 return false; // wrong entry type; not our special case
1184 }
1185
1186 if (t1 == t2) {
1187 return false; // not a mismatch; not our special case
1188 }
1189
1190 char *s1 = cp1->klass_name_at(index1)->as_C_string();
1191 char *s2 = cp2->klass_name_at(index2)->as_C_string();
1192 if (strcmp(s1, s2) != 0) {
1193 return false; // strings don't match; not our special case
1194 }
1195
1196 return true; // made it through the gauntlet; this is our special case
1197 } // end is_unresolved_class_mismatch()
1198
1199
1200 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1201
1202 // For consistency allocate memory using os::malloc wrapper.
1203 _scratch_classes = (InstanceKlass**)
1204 os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass);
1205 if (_scratch_classes == NULL) {
1206 return JVMTI_ERROR_OUT_OF_MEMORY;
1207 }
1208 // Zero initialize the _scratch_classes array.
1209 for (int i = 0; i < _class_count; i++) {
1210 _scratch_classes[i] = NULL;
1211 }
1212
1213 ResourceMark rm(THREAD);
1214
1215 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1216 // state can only be NULL if the current thread is exiting which
1217 // should not happen since we're trying to do a RedefineClasses
1218 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1219 for (int i = 0; i < _class_count; i++) {
1220 // Create HandleMark so that any handles created while loading new class
1221 // versions are deleted. Constant pools are deallocated while merging
1222 // constant pools
1223 HandleMark hm(THREAD);
1224 InstanceKlass* the_class = get_ik(_class_defs[i].klass);
1225 Symbol* the_class_sym = the_class->name();
1226
1227 log_debug(redefine, class, load)
1228 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1229 the_class->external_name(), _class_load_kind, os::available_memory() >> 10);
1230
1231 ClassFileStream st((u1*)_class_defs[i].class_bytes,
1232 _class_defs[i].class_byte_count,
1233 "__VM_RedefineClasses__",
1234 ClassFileStream::verify);
1235
1236 // Parse the stream.
1237 Handle the_class_loader(THREAD, the_class->class_loader());
1238 Handle protection_domain(THREAD, the_class->protection_domain());
1239 // Set redefined class handle in JvmtiThreadState class.
1240 // This redefined class is sent to agent event handler for class file
1241 // load hook event.
1242 state->set_class_being_redefined(the_class, _class_load_kind);
1243
1244 ClassLoadInfo cl_info(protection_domain);
1245 InstanceKlass* scratch_class = SystemDictionary::parse_stream(
1246 the_class_sym,
1247 the_class_loader,
1248 &st,
1249 cl_info,
1250 THREAD);
1251 // Clear class_being_redefined just to be sure.
1252 state->clear_class_being_redefined();
1253
1254 // TODO: if this is retransform, and nothing changed we can skip it
1255
1256 // Need to clean up allocated InstanceKlass if there's an error so assign
1257 // the result here. Caller deallocates all the scratch classes in case of
1258 // an error.
1259 _scratch_classes[i] = scratch_class;
1260
1261 if (HAS_PENDING_EXCEPTION) {
1262 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1263 log_info(redefine, class, load, exceptions)("parse_stream exception: '%s'", ex_name->as_C_string());
1264 CLEAR_PENDING_EXCEPTION;
1265
1266 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1267 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1268 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1269 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1270 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1271 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1272 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1273 // The message will be "XXX (wrong name: YYY)"
1274 return JVMTI_ERROR_NAMES_DONT_MATCH;
1275 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1276 return JVMTI_ERROR_OUT_OF_MEMORY;
1277 } else { // Just in case more exceptions can be thrown..
1278 return JVMTI_ERROR_FAILS_VERIFICATION;
1279 }
1280 }
1281
1282 // Ensure class is linked before redefine
1283 if (!the_class->is_linked()) {
1284 the_class->link_class(THREAD);
1285 if (HAS_PENDING_EXCEPTION) {
1286 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1287 log_info(redefine, class, load, exceptions)("link_class exception: '%s'", ex_name->as_C_string());
1288 CLEAR_PENDING_EXCEPTION;
1289 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1290 return JVMTI_ERROR_OUT_OF_MEMORY;
1291 } else {
1292 return JVMTI_ERROR_INTERNAL;
1293 }
1294 }
1295 }
1296
1297 // Do the validity checks in compare_and_normalize_class_versions()
1298 // before verifying the byte codes. By doing these checks first, we
1299 // limit the number of functions that require redirection from
1300 // the_class to scratch_class. In particular, we don't have to
1301 // modify JNI GetSuperclass() and thus won't change its performance.
1302 jvmtiError res = compare_and_normalize_class_versions(the_class,
1303 scratch_class);
1304 if (res != JVMTI_ERROR_NONE) {
1305 return res;
1306 }
1307
1308 // verify what the caller passed us
1309 {
1310 // The bug 6214132 caused the verification to fail.
1311 // Information about the_class and scratch_class is temporarily
1312 // recorded into jvmtiThreadState. This data is used to redirect
1313 // the_class to scratch_class in the JVM_* functions called by the
1314 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1315 // description.
1316 RedefineVerifyMark rvm(the_class, scratch_class, state);
1317 Verifier::verify(scratch_class, true, THREAD);
1318 }
1319
1320 if (HAS_PENDING_EXCEPTION) {
1321 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1322 log_info(redefine, class, load, exceptions)("verify_byte_codes exception: '%s'", ex_name->as_C_string());
1323 CLEAR_PENDING_EXCEPTION;
1324 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1325 return JVMTI_ERROR_OUT_OF_MEMORY;
1326 } else {
1327 // tell the caller the bytecodes are bad
1328 return JVMTI_ERROR_FAILS_VERIFICATION;
1329 }
1330 }
1331
1332 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1333 if (HAS_PENDING_EXCEPTION) {
1334 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1335 log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string());
1336 CLEAR_PENDING_EXCEPTION;
1337 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1338 return JVMTI_ERROR_OUT_OF_MEMORY;
1339 } else {
1340 return JVMTI_ERROR_INTERNAL;
1341 }
1342 }
1343
1344 if (VerifyMergedCPBytecodes) {
1345 // verify what we have done during constant pool merging
1346 {
1347 RedefineVerifyMark rvm(the_class, scratch_class, state);
1348 Verifier::verify(scratch_class, true, THREAD);
1349 }
1350
1351 if (HAS_PENDING_EXCEPTION) {
1352 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1353 log_info(redefine, class, load, exceptions)
1354 ("verify_byte_codes post merge-CP exception: '%s'", ex_name->as_C_string());
1355 CLEAR_PENDING_EXCEPTION;
1356 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1357 return JVMTI_ERROR_OUT_OF_MEMORY;
1358 } else {
1359 // tell the caller that constant pool merging screwed up
1360 return JVMTI_ERROR_INTERNAL;
1361 }
1362 }
1363 }
1364
1365 Rewriter::rewrite(scratch_class, THREAD);
1366 if (!HAS_PENDING_EXCEPTION) {
1367 scratch_class->link_methods(THREAD);
1368 }
1369 if (HAS_PENDING_EXCEPTION) {
1370 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1371 log_info(redefine, class, load, exceptions)
1372 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string());
1373 CLEAR_PENDING_EXCEPTION;
1374 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1375 return JVMTI_ERROR_OUT_OF_MEMORY;
1376 } else {
1377 return JVMTI_ERROR_INTERNAL;
1378 }
1379 }
1380
1381 log_debug(redefine, class, load)
1382 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", the_class->external_name(), os::available_memory() >> 10);
1383 }
1384
1385 return JVMTI_ERROR_NONE;
1386 }
1387
1388
1389 // Map old_index to new_index as needed. scratch_cp is only needed
1390 // for log calls.
1391 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1392 int old_index, int new_index) {
1393 if (find_new_index(old_index) != 0) {
1394 // old_index is already mapped
1395 return;
1396 }
1397
1398 if (old_index == new_index) {
1399 // no mapping is needed
1400 return;
1401 }
1402
1403 _index_map_p->at_put(old_index, new_index);
1404 _index_map_count++;
1405
1406 log_trace(redefine, class, constantpool)
1407 ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index);
1408 } // end map_index()
1409
1410
1411 // Map old_index to new_index as needed.
1412 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1413 if (find_new_operand_index(old_index) != -1) {
1414 // old_index is already mapped
1415 return;
1416 }
1417
1418 if (old_index == new_index) {
1419 // no mapping is needed
1420 return;
1421 }
1422
1423 _operands_index_map_p->at_put(old_index, new_index);
1424 _operands_index_map_count++;
1425
1426 log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", old_index, new_index);
1427 } // end map_index()
1428
1429
1430 // Merge old_cp and scratch_cp and return the results of the merge via
1431 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1432 // merge_cp_length_p. The entries in old_cp occupy the same locations
1433 // in *merge_cp_p. Also creates a map of indices from entries in
1434 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1435 // entries are only created for entries in scratch_cp that occupy a
1436 // different location in *merged_cp_p.
1437 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1438 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1439 int *merge_cp_length_p, TRAPS) {
1440
1441 if (merge_cp_p == NULL) {
1442 assert(false, "caller must provide scratch constantPool");
1443 return false; // robustness
1444 }
1445 if (merge_cp_length_p == NULL) {
1446 assert(false, "caller must provide scratch CP length");
1447 return false; // robustness
1448 }
1449 // Worst case we need old_cp->length() + scratch_cp()->length(),
1450 // but the caller might be smart so make sure we have at least
1451 // the minimum.
1452 if ((*merge_cp_p)->length() < old_cp->length()) {
1453 assert(false, "merge area too small");
1454 return false; // robustness
1455 }
1456
1457 log_info(redefine, class, constantpool)("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), scratch_cp->length());
1458
1459 {
1460 // Pass 0:
1461 // The old_cp is copied to *merge_cp_p; this means that any code
1462 // using old_cp does not have to change. This work looks like a
1463 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1464 // handle one special case:
1465 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1466 // This will make verification happy.
1467
1468 int old_i; // index into old_cp
1469
1470 // index zero (0) is not used in constantPools
1471 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1472 // leave debugging crumb
1473 jbyte old_tag = old_cp->tag_at(old_i).value();
1474 switch (old_tag) {
1475 case JVM_CONSTANT_Class:
1476 case JVM_CONSTANT_UnresolvedClass:
1477 // revert the copy to JVM_CONSTANT_UnresolvedClass
1478 // May be resolving while calling this so do the same for
1479 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1480 (*merge_cp_p)->temp_unresolved_klass_at_put(old_i,
1481 old_cp->klass_name_index_at(old_i));
1482 break;
1483
1484 case JVM_CONSTANT_Double:
1485 case JVM_CONSTANT_Long:
1486 // just copy the entry to *merge_cp_p, but double and long take
1487 // two constant pool entries
1488 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_false);
1489 old_i++;
1490 break;
1491
1492 default:
1493 // just copy the entry to *merge_cp_p
1494 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_false);
1495 break;
1496 }
1497 } // end for each old_cp entry
1498
1499 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_false);
1500 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_false);
1501
1502 // We don't need to sanity check that *merge_cp_length_p is within
1503 // *merge_cp_p bounds since we have the minimum on-entry check above.
1504 (*merge_cp_length_p) = old_i;
1505 }
1506
1507 // merge_cp_len should be the same as old_cp->length() at this point
1508 // so this trace message is really a "warm-and-breathing" message.
1509 log_debug(redefine, class, constantpool)("after pass 0: merge_cp_len=%d", *merge_cp_length_p);
1510
1511 int scratch_i; // index into scratch_cp
1512 {
1513 // Pass 1a:
1514 // Compare scratch_cp entries to the old_cp entries that we have
1515 // already copied to *merge_cp_p. In this pass, we are eliminating
1516 // exact duplicates (matching entry at same index) so we only
1517 // compare entries in the common indice range.
1518 int increment = 1;
1519 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1520 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1521 switch (scratch_cp->tag_at(scratch_i).value()) {
1522 case JVM_CONSTANT_Double:
1523 case JVM_CONSTANT_Long:
1524 // double and long take two constant pool entries
1525 increment = 2;
1526 break;
1527
1528 default:
1529 increment = 1;
1530 break;
1531 }
1532
1533 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1534 scratch_i, CHECK_false);
1535 if (match) {
1536 // found a match at the same index so nothing more to do
1537 continue;
1538 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1539 *merge_cp_p, scratch_i)) {
1540 // The mismatch in compare_entry_to() above is because of a
1541 // resolved versus unresolved class entry at the same index
1542 // with the same string value. Since Pass 0 reverted any
1543 // class entries to unresolved class entries in *merge_cp_p,
1544 // we go with the unresolved class entry.
1545 continue;
1546 }
1547
1548 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1549 CHECK_false);
1550 if (found_i != 0) {
1551 guarantee(found_i != scratch_i,
1552 "compare_entry_to() and find_matching_entry() do not agree");
1553
1554 // Found a matching entry somewhere else in *merge_cp_p so
1555 // just need a mapping entry.
1556 map_index(scratch_cp, scratch_i, found_i);
1557 continue;
1558 }
1559
1560 // The find_matching_entry() call above could fail to find a match
1561 // due to a resolved versus unresolved class or string entry situation
1562 // like we solved above with the is_unresolved_*_mismatch() calls.
1563 // However, we would have to call is_unresolved_*_mismatch() over
1564 // all of *merge_cp_p (potentially) and that doesn't seem to be
1565 // worth the time.
1566
1567 // No match found so we have to append this entry and any unique
1568 // referenced entries to *merge_cp_p.
1569 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1570 CHECK_false);
1571 }
1572 }
1573
1574 log_debug(redefine, class, constantpool)
1575 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1576 *merge_cp_length_p, scratch_i, _index_map_count);
1577
1578 if (scratch_i < scratch_cp->length()) {
1579 // Pass 1b:
1580 // old_cp is smaller than scratch_cp so there are entries in
1581 // scratch_cp that we have not yet processed. We take care of
1582 // those now.
1583 int increment = 1;
1584 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1585 switch (scratch_cp->tag_at(scratch_i).value()) {
1586 case JVM_CONSTANT_Double:
1587 case JVM_CONSTANT_Long:
1588 // double and long take two constant pool entries
1589 increment = 2;
1590 break;
1591
1592 default:
1593 increment = 1;
1594 break;
1595 }
1596
1597 int found_i =
1598 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_false);
1599 if (found_i != 0) {
1600 // Found a matching entry somewhere else in *merge_cp_p so
1601 // just need a mapping entry.
1602 map_index(scratch_cp, scratch_i, found_i);
1603 continue;
1604 }
1605
1606 // No match found so we have to append this entry and any unique
1607 // referenced entries to *merge_cp_p.
1608 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1609 CHECK_false);
1610 }
1611
1612 log_debug(redefine, class, constantpool)
1613 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1614 *merge_cp_length_p, scratch_i, _index_map_count);
1615 }
1616 finalize_operands_merge(*merge_cp_p, THREAD);
1617
1618 return true;
1619 } // end merge_constant_pools()
1620
1621
1622 // Scoped object to clean up the constant pool(s) created for merging
1623 class MergeCPCleaner {
1624 ClassLoaderData* _loader_data;
1625 ConstantPool* _cp;
1626 ConstantPool* _scratch_cp;
1627 public:
1628 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1629 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1630 ~MergeCPCleaner() {
1631 _loader_data->add_to_deallocate_list(_cp);
1632 if (_scratch_cp != NULL) {
1633 _loader_data->add_to_deallocate_list(_scratch_cp);
1634 }
1635 }
1636 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1637 };
1638
1639 // Merge constant pools between the_class and scratch_class and
1640 // potentially rewrite bytecodes in scratch_class to use the merged
1641 // constant pool.
1642 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1643 InstanceKlass* the_class, InstanceKlass* scratch_class,
1644 TRAPS) {
1645 // worst case merged constant pool length is old and new combined
1646 int merge_cp_length = the_class->constants()->length()
1647 + scratch_class->constants()->length();
1648
1649 // Constant pools are not easily reused so we allocate a new one
1650 // each time.
1651 // merge_cp is created unsafe for concurrent GC processing. It
1652 // should be marked safe before discarding it. Even though
1653 // garbage, if it crosses a card boundary, it may be scanned
1654 // in order to find the start of the first complete object on the card.
1655 ClassLoaderData* loader_data = the_class->class_loader_data();
1656 ConstantPool* merge_cp_oop =
1657 ConstantPool::allocate(loader_data,
1658 merge_cp_length,
1659 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1660 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1661
1662 HandleMark hm(THREAD); // make sure handles are cleared before
1663 // MergeCPCleaner clears out merge_cp_oop
1664 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1665
1666 // Get constants() from the old class because it could have been rewritten
1667 // while we were at a safepoint allocating a new constant pool.
1668 constantPoolHandle old_cp(THREAD, the_class->constants());
1669 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1670
1671 // If the length changed, the class was redefined out from under us. Return
1672 // an error.
1673 if (merge_cp_length != the_class->constants()->length()
1674 + scratch_class->constants()->length()) {
1675 return JVMTI_ERROR_INTERNAL;
1676 }
1677
1678 // Update the version number of the constant pools (may keep scratch_cp)
1679 merge_cp->increment_and_save_version(old_cp->version());
1680 scratch_cp->increment_and_save_version(old_cp->version());
1681
1682 ResourceMark rm(THREAD);
1683 _index_map_count = 0;
1684 _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1);
1685
1686 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1687 _operands_index_map_count = 0;
1688 int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands());
1689 _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1);
1690
1691 // reference to the cp holder is needed for copy_operands()
1692 merge_cp->set_pool_holder(scratch_class);
1693 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1694 &merge_cp_length, THREAD);
1695 merge_cp->set_pool_holder(NULL);
1696
1697 if (!result) {
1698 // The merge can fail due to memory allocation failure or due
1699 // to robustness checks.
1700 return JVMTI_ERROR_INTERNAL;
1701 }
1702
1703 if (old_cp->has_dynamic_constant()) {
1704 merge_cp->set_has_dynamic_constant();
1705 scratch_cp->set_has_dynamic_constant();
1706 }
1707
1708 log_info(redefine, class, constantpool)("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count);
1709
1710 if (_index_map_count == 0) {
1711 // there is nothing to map between the new and merged constant pools
1712
1713 if (old_cp->length() == scratch_cp->length()) {
1714 // The old and new constant pools are the same length and the
1715 // index map is empty. This means that the three constant pools
1716 // are equivalent (but not the same). Unfortunately, the new
1717 // constant pool has not gone through link resolution nor have
1718 // the new class bytecodes gone through constant pool cache
1719 // rewriting so we can't use the old constant pool with the new
1720 // class.
1721
1722 // toss the merged constant pool at return
1723 } else if (old_cp->length() < scratch_cp->length()) {
1724 // The old constant pool has fewer entries than the new constant
1725 // pool and the index map is empty. This means the new constant
1726 // pool is a superset of the old constant pool. However, the old
1727 // class bytecodes have already gone through constant pool cache
1728 // rewriting so we can't use the new constant pool with the old
1729 // class.
1730
1731 // toss the merged constant pool at return
1732 } else {
1733 // The old constant pool has more entries than the new constant
1734 // pool and the index map is empty. This means that both the old
1735 // and merged constant pools are supersets of the new constant
1736 // pool.
1737
1738 // Replace the new constant pool with a shrunken copy of the
1739 // merged constant pool
1740 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1741 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1742 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1743 // It can't be cleaned up while there are handles to it.
1744 cp_cleaner.add_scratch_cp(scratch_cp());
1745 }
1746 } else {
1747 if (log_is_enabled(Trace, redefine, class, constantpool)) {
1748 // don't want to loop unless we are tracing
1749 int count = 0;
1750 for (int i = 1; i < _index_map_p->length(); i++) {
1751 int value = _index_map_p->at(i);
1752
1753 if (value != -1) {
1754 log_trace(redefine, class, constantpool)("index_map[%d]: old=%d new=%d", count, i, value);
1755 count++;
1756 }
1757 }
1758 }
1759
1760 // We have entries mapped between the new and merged constant pools
1761 // so we have to rewrite some constant pool references.
1762 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1763 return JVMTI_ERROR_INTERNAL;
1764 }
1765
1766 // Replace the new constant pool with a shrunken copy of the
1767 // merged constant pool so now the rewritten bytecodes have
1768 // valid references; the previous new constant pool will get
1769 // GCed.
1770 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1771 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1772 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1773 // It can't be cleaned up while there are handles to it.
1774 cp_cleaner.add_scratch_cp(scratch_cp());
1775 }
1776
1777 return JVMTI_ERROR_NONE;
1778 } // end merge_cp_and_rewrite()
1779
1780
1781 // Rewrite constant pool references in klass scratch_class.
1782 bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class,
1783 TRAPS) {
1784
1785 // rewrite constant pool references in the nest attributes:
1786 if (!rewrite_cp_refs_in_nest_attributes(scratch_class)) {
1787 // propagate failure back to caller
1788 return false;
1789 }
1790
1791 // rewrite constant pool references in the Record attribute:
1792 if (!rewrite_cp_refs_in_record_attribute(scratch_class, THREAD)) {
1793 // propagate failure back to caller
1794 return false;
1795 }
1796
1797 // rewrite constant pool references in the methods:
1798 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1799 // propagate failure back to caller
1800 return false;
1801 }
1802
1803 // rewrite constant pool references in the class_annotations:
1804 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1805 // propagate failure back to caller
1806 return false;
1807 }
1808
1809 // rewrite constant pool references in the fields_annotations:
1810 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1811 // propagate failure back to caller
1812 return false;
1813 }
1814
1815 // rewrite constant pool references in the methods_annotations:
1816 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1817 // propagate failure back to caller
1818 return false;
1819 }
1820
1821 // rewrite constant pool references in the methods_parameter_annotations:
1822 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1823 THREAD)) {
1824 // propagate failure back to caller
1825 return false;
1826 }
1827
1828 // rewrite constant pool references in the methods_default_annotations:
1829 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1830 THREAD)) {
1831 // propagate failure back to caller
1832 return false;
1833 }
1834
1835 // rewrite constant pool references in the class_type_annotations:
1836 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1837 // propagate failure back to caller
1838 return false;
1839 }
1840
1841 // rewrite constant pool references in the fields_type_annotations:
1842 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1843 // propagate failure back to caller
1844 return false;
1845 }
1846
1847 // rewrite constant pool references in the methods_type_annotations:
1848 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1849 // propagate failure back to caller
1850 return false;
1851 }
1852
1853 // There can be type annotations in the Code part of a method_info attribute.
1854 // These annotations are not accessible, even by reflection.
1855 // Currently they are not even parsed by the ClassFileParser.
1856 // If runtime access is added they will also need to be rewritten.
1857
1858 // rewrite source file name index:
1859 u2 source_file_name_idx = scratch_class->source_file_name_index();
1860 if (source_file_name_idx != 0) {
1861 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1862 if (new_source_file_name_idx != 0) {
1863 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1864 }
1865 }
1866
1867 // rewrite class generic signature index:
1868 u2 generic_signature_index = scratch_class->generic_signature_index();
1869 if (generic_signature_index != 0) {
1870 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1871 if (new_generic_signature_index != 0) {
1872 scratch_class->set_generic_signature_index(new_generic_signature_index);
1873 }
1874 }
1875
1876 return true;
1877 } // end rewrite_cp_refs()
1878
1879 // Rewrite constant pool references in the NestHost and NestMembers attributes.
1880 bool VM_RedefineClasses::rewrite_cp_refs_in_nest_attributes(
1881 InstanceKlass* scratch_class) {
1882
1883 u2 cp_index = scratch_class->nest_host_index();
1884 if (cp_index != 0) {
1885 scratch_class->set_nest_host_index(find_new_index(cp_index));
1886 }
1887 Array<u2>* nest_members = scratch_class->nest_members();
1888 for (int i = 0; i < nest_members->length(); i++) {
1889 u2 cp_index = nest_members->at(i);
1890 nest_members->at_put(i, find_new_index(cp_index));
1891 }
1892 return true;
1893 }
1894
1895 // Rewrite constant pool references in the Record attribute.
1896 bool VM_RedefineClasses::rewrite_cp_refs_in_record_attribute(
1897 InstanceKlass* scratch_class, TRAPS) {
1898 Array<RecordComponent*>* components = scratch_class->record_components();
1899 if (components != NULL) {
1900 for (int i = 0; i < components->length(); i++) {
1901 RecordComponent* component = components->at(i);
1902 u2 cp_index = component->name_index();
1903 component->set_name_index(find_new_index(cp_index));
1904 cp_index = component->descriptor_index();
1905 component->set_descriptor_index(find_new_index(cp_index));
1906 cp_index = component->generic_signature_index();
1907 if (cp_index != 0) {
1908 component->set_generic_signature_index(find_new_index(cp_index));
1909 }
1910
1911 AnnotationArray* annotations = component->annotations();
1912 if (annotations != NULL && annotations->length() != 0) {
1913 int byte_i = 0; // byte index into annotations
1914 if (!rewrite_cp_refs_in_annotations_typeArray(annotations, byte_i, THREAD)) {
1915 log_debug(redefine, class, annotation)("bad record_component_annotations at %d", i);
1916 // propagate failure back to caller
1917 return false;
1918 }
1919 }
1920
1921 AnnotationArray* type_annotations = component->type_annotations();
1922 if (type_annotations != NULL && type_annotations->length() != 0) {
1923 int byte_i = 0; // byte index into annotations
1924 if (!rewrite_cp_refs_in_annotations_typeArray(type_annotations, byte_i, THREAD)) {
1925 log_debug(redefine, class, annotation)("bad record_component_type_annotations at %d", i);
1926 // propagate failure back to caller
1927 return false;
1928 }
1929 }
1930 }
1931 }
1932 return true;
1933 }
1934
1935 // Rewrite constant pool references in the methods.
1936 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1937 InstanceKlass* scratch_class, TRAPS) {
1938
1939 Array<Method*>* methods = scratch_class->methods();
1940
1941 if (methods == NULL || methods->length() == 0) {
1942 // no methods so nothing to do
1943 return true;
1944 }
1945
1946 // rewrite constant pool references in the methods:
1947 for (int i = methods->length() - 1; i >= 0; i--) {
1948 methodHandle method(THREAD, methods->at(i));
1949 methodHandle new_method;
1950 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1951 if (!new_method.is_null()) {
1952 // the method has been replaced so save the new method version
1953 // even in the case of an exception. original method is on the
1954 // deallocation list.
1955 methods->at_put(i, new_method());
1956 }
1957 if (HAS_PENDING_EXCEPTION) {
1958 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1959 log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string());
1960 // Need to clear pending exception here as the super caller sets
1961 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1962 CLEAR_PENDING_EXCEPTION;
1963 return false;
1964 }
1965 }
1966
1967 return true;
1968 }
1969
1970
1971 // Rewrite constant pool references in the specific method. This code
1972 // was adapted from Rewriter::rewrite_method().
1973 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1974 methodHandle *new_method_p, TRAPS) {
1975
1976 *new_method_p = methodHandle(); // default is no new method
1977
1978 // We cache a pointer to the bytecodes here in code_base. If GC
1979 // moves the Method*, then the bytecodes will also move which
1980 // will likely cause a crash. We create a NoSafepointVerifier
1981 // object to detect whether we pass a possible safepoint in this
1982 // code block.
1983 NoSafepointVerifier nsv;
1984
1985 // Bytecodes and their length
1986 address code_base = method->code_base();
1987 int code_length = method->code_size();
1988
1989 int bc_length;
1990 for (int bci = 0; bci < code_length; bci += bc_length) {
1991 address bcp = code_base + bci;
1992 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1993
1994 bc_length = Bytecodes::length_for(c);
1995 if (bc_length == 0) {
1996 // More complicated bytecodes report a length of zero so
1997 // we have to try again a slightly different way.
1998 bc_length = Bytecodes::length_at(method(), bcp);
1999 }
2000
2001 assert(bc_length != 0, "impossible bytecode length");
2002
2003 switch (c) {
2004 case Bytecodes::_ldc:
2005 {
2006 int cp_index = *(bcp + 1);
2007 int new_index = find_new_index(cp_index);
2008
2009 if (StressLdcRewrite && new_index == 0) {
2010 // If we are stressing ldc -> ldc_w rewriting, then we
2011 // always need a new_index value.
2012 new_index = cp_index;
2013 }
2014 if (new_index != 0) {
2015 // the original index is mapped so we have more work to do
2016 if (!StressLdcRewrite && new_index <= max_jubyte) {
2017 // The new value can still use ldc instead of ldc_w
2018 // unless we are trying to stress ldc -> ldc_w rewriting
2019 log_trace(redefine, class, constantpool)
2020 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2021 *(bcp + 1) = new_index;
2022 } else {
2023 log_trace(redefine, class, constantpool)
2024 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index);
2025 // the new value needs ldc_w instead of ldc
2026 u_char inst_buffer[4]; // max instruction size is 4 bytes
2027 bcp = (address)inst_buffer;
2028 // construct new instruction sequence
2029 *bcp = Bytecodes::_ldc_w;
2030 bcp++;
2031 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
2032 // See comment below for difference between put_Java_u2()
2033 // and put_native_u2().
2034 Bytes::put_Java_u2(bcp, new_index);
2035
2036 Relocator rc(method, NULL /* no RelocatorListener needed */);
2037 methodHandle m;
2038 {
2039 PauseNoSafepointVerifier pnsv(&nsv);
2040
2041 // ldc is 2 bytes and ldc_w is 3 bytes
2042 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
2043 }
2044
2045 // return the new method so that the caller can update
2046 // the containing class
2047 *new_method_p = method = m;
2048 // switch our bytecode processing loop from the old method
2049 // to the new method
2050 code_base = method->code_base();
2051 code_length = method->code_size();
2052 bcp = code_base + bci;
2053 c = (Bytecodes::Code)(*bcp);
2054 bc_length = Bytecodes::length_for(c);
2055 assert(bc_length != 0, "sanity check");
2056 } // end we need ldc_w instead of ldc
2057 } // end if there is a mapped index
2058 } break;
2059
2060 // these bytecodes have a two-byte constant pool index
2061 case Bytecodes::_anewarray : // fall through
2062 case Bytecodes::_checkcast : // fall through
2063 case Bytecodes::_getfield : // fall through
2064 case Bytecodes::_getstatic : // fall through
2065 case Bytecodes::_instanceof : // fall through
2066 case Bytecodes::_invokedynamic : // fall through
2067 case Bytecodes::_invokeinterface: // fall through
2068 case Bytecodes::_invokespecial : // fall through
2069 case Bytecodes::_invokestatic : // fall through
2070 case Bytecodes::_invokevirtual : // fall through
2071 case Bytecodes::_ldc_w : // fall through
2072 case Bytecodes::_ldc2_w : // fall through
2073 case Bytecodes::_multianewarray : // fall through
2074 case Bytecodes::_new : // fall through
2075 case Bytecodes::_putfield : // fall through
2076 case Bytecodes::_putstatic :
2077 {
2078 address p = bcp + 1;
2079 int cp_index = Bytes::get_Java_u2(p);
2080 int new_index = find_new_index(cp_index);
2081 if (new_index != 0) {
2082 // the original index is mapped so update w/ new value
2083 log_trace(redefine, class, constantpool)
2084 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(bcp), cp_index, new_index);
2085 // Rewriter::rewrite_method() uses put_native_u2() in this
2086 // situation because it is reusing the constant pool index
2087 // location for a native index into the ConstantPoolCache.
2088 // Since we are updating the constant pool index prior to
2089 // verification and ConstantPoolCache initialization, we
2090 // need to keep the new index in Java byte order.
2091 Bytes::put_Java_u2(p, new_index);
2092 }
2093 } break;
2094 default:
2095 break;
2096 }
2097 } // end for each bytecode
2098
2099 // We also need to rewrite the parameter name indexes, if there is
2100 // method parameter data present
2101 if(method->has_method_parameters()) {
2102 const int len = method->method_parameters_length();
2103 MethodParametersElement* elem = method->method_parameters_start();
2104
2105 for (int i = 0; i < len; i++) {
2106 const u2 cp_index = elem[i].name_cp_index;
2107 const u2 new_cp_index = find_new_index(cp_index);
2108 if (new_cp_index != 0) {
2109 elem[i].name_cp_index = new_cp_index;
2110 }
2111 }
2112 }
2113 } // end rewrite_cp_refs_in_method()
2114
2115
2116 // Rewrite constant pool references in the class_annotations field.
2117 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
2118 InstanceKlass* scratch_class, TRAPS) {
2119
2120 AnnotationArray* class_annotations = scratch_class->class_annotations();
2121 if (class_annotations == NULL || class_annotations->length() == 0) {
2122 // no class_annotations so nothing to do
2123 return true;
2124 }
2125
2126 log_debug(redefine, class, annotation)("class_annotations length=%d", class_annotations->length());
2127
2128 int byte_i = 0; // byte index into class_annotations
2129 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
2130 THREAD);
2131 }
2132
2133
2134 // Rewrite constant pool references in an annotations typeArray. This
2135 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
2136 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
2137 //
2138 // annotations_typeArray {
2139 // u2 num_annotations;
2140 // annotation annotations[num_annotations];
2141 // }
2142 //
2143 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
2144 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2145
2146 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2147 // not enough room for num_annotations field
2148 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2149 return false;
2150 }
2151
2152 u2 num_annotations = Bytes::get_Java_u2((address)
2153 annotations_typeArray->adr_at(byte_i_ref));
2154 byte_i_ref += 2;
2155
2156 log_debug(redefine, class, annotation)("num_annotations=%d", num_annotations);
2157
2158 int calc_num_annotations = 0;
2159 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2160 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2161 byte_i_ref, THREAD)) {
2162 log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations);
2163 // propagate failure back to caller
2164 return false;
2165 }
2166 }
2167 assert(num_annotations == calc_num_annotations, "sanity check");
2168
2169 return true;
2170 } // end rewrite_cp_refs_in_annotations_typeArray()
2171
2172
2173 // Rewrite constant pool references in the annotation struct portion of
2174 // an annotations_typeArray. This "structure" is from section 4.8.15 of
2175 // the 2nd-edition of the VM spec:
2176 //
2177 // struct annotation {
2178 // u2 type_index;
2179 // u2 num_element_value_pairs;
2180 // {
2181 // u2 element_name_index;
2182 // element_value value;
2183 // } element_value_pairs[num_element_value_pairs];
2184 // }
2185 //
2186 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
2187 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2188 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
2189 // not enough room for smallest annotation_struct
2190 log_debug(redefine, class, annotation)("length() is too small for annotation_struct");
2191 return false;
2192 }
2193
2194 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
2195 byte_i_ref, "type_index", THREAD);
2196
2197 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
2198 annotations_typeArray->adr_at(byte_i_ref));
2199 byte_i_ref += 2;
2200
2201 log_debug(redefine, class, annotation)
2202 ("type_index=%d num_element_value_pairs=%d", type_index, num_element_value_pairs);
2203
2204 int calc_num_element_value_pairs = 0;
2205 for (; calc_num_element_value_pairs < num_element_value_pairs;
2206 calc_num_element_value_pairs++) {
2207 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2208 // not enough room for another element_name_index, let alone
2209 // the rest of another component
2210 log_debug(redefine, class, annotation)("length() is too small for element_name_index");
2211 return false;
2212 }
2213
2214 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
2215 annotations_typeArray, byte_i_ref,
2216 "element_name_index", THREAD);
2217
2218 log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index);
2219
2220 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
2221 byte_i_ref, THREAD)) {
2222 log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs);
2223 // propagate failure back to caller
2224 return false;
2225 }
2226 } // end for each component
2227 assert(num_element_value_pairs == calc_num_element_value_pairs,
2228 "sanity check");
2229
2230 return true;
2231 } // end rewrite_cp_refs_in_annotation_struct()
2232
2233
2234 // Rewrite a constant pool reference at the current position in
2235 // annotations_typeArray if needed. Returns the original constant
2236 // pool reference if a rewrite was not needed or the new constant
2237 // pool reference if a rewrite was needed.
2238 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
2239 AnnotationArray* annotations_typeArray, int &byte_i_ref,
2240 const char * trace_mesg, TRAPS) {
2241
2242 address cp_index_addr = (address)
2243 annotations_typeArray->adr_at(byte_i_ref);
2244 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
2245 u2 new_cp_index = find_new_index(old_cp_index);
2246 if (new_cp_index != 0) {
2247 log_debug(redefine, class, annotation)("mapped old %s=%d", trace_mesg, old_cp_index);
2248 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
2249 old_cp_index = new_cp_index;
2250 }
2251 byte_i_ref += 2;
2252 return old_cp_index;
2253 }
2254
2255
2256 // Rewrite constant pool references in the element_value portion of an
2257 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
2258 // the 2nd-edition of the VM spec:
2259 //
2260 // struct element_value {
2261 // u1 tag;
2262 // union {
2263 // u2 const_value_index;
2264 // {
2265 // u2 type_name_index;
2266 // u2 const_name_index;
2267 // } enum_const_value;
2268 // u2 class_info_index;
2269 // annotation annotation_value;
2270 // struct {
2271 // u2 num_values;
2272 // element_value values[num_values];
2273 // } array_value;
2274 // } value;
2275 // }
2276 //
2277 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
2278 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
2279
2280 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
2281 // not enough room for a tag let alone the rest of an element_value
2282 log_debug(redefine, class, annotation)("length() is too small for a tag");
2283 return false;
2284 }
2285
2286 u1 tag = annotations_typeArray->at(byte_i_ref);
2287 byte_i_ref++;
2288 log_debug(redefine, class, annotation)("tag='%c'", tag);
2289
2290 switch (tag) {
2291 // These BaseType tag values are from Table 4.2 in VM spec:
2292 case JVM_SIGNATURE_BYTE:
2293 case JVM_SIGNATURE_CHAR:
2294 case JVM_SIGNATURE_DOUBLE:
2295 case JVM_SIGNATURE_FLOAT:
2296 case JVM_SIGNATURE_INT:
2297 case JVM_SIGNATURE_LONG:
2298 case JVM_SIGNATURE_SHORT:
2299 case JVM_SIGNATURE_BOOLEAN:
2300
2301 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2302 // the VM spec:
2303 case 's':
2304 {
2305 // For the above tag values (including the BaseType values),
2306 // value.const_value_index is right union field.
2307
2308 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2309 // not enough room for a const_value_index
2310 log_debug(redefine, class, annotation)("length() is too small for a const_value_index");
2311 return false;
2312 }
2313
2314 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2315 annotations_typeArray, byte_i_ref,
2316 "const_value_index", THREAD);
2317
2318 log_debug(redefine, class, annotation)("const_value_index=%d", const_value_index);
2319 } break;
2320
2321 case 'e':
2322 {
2323 // for the above tag value, value.enum_const_value is right union field
2324
2325 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2326 // not enough room for a enum_const_value
2327 log_debug(redefine, class, annotation)("length() is too small for a enum_const_value");
2328 return false;
2329 }
2330
2331 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2332 annotations_typeArray, byte_i_ref,
2333 "type_name_index", THREAD);
2334
2335 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2336 annotations_typeArray, byte_i_ref,
2337 "const_name_index", THREAD);
2338
2339 log_debug(redefine, class, annotation)
2340 ("type_name_index=%d const_name_index=%d", type_name_index, const_name_index);
2341 } break;
2342
2343 case 'c':
2344 {
2345 // for the above tag value, value.class_info_index is right union field
2346
2347 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2348 // not enough room for a class_info_index
2349 log_debug(redefine, class, annotation)("length() is too small for a class_info_index");
2350 return false;
2351 }
2352
2353 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2354 annotations_typeArray, byte_i_ref,
2355 "class_info_index", THREAD);
2356
2357 log_debug(redefine, class, annotation)("class_info_index=%d", class_info_index);
2358 } break;
2359
2360 case '@':
2361 // For the above tag value, value.attr_value is the right union
2362 // field. This is a nested annotation.
2363 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2364 byte_i_ref, THREAD)) {
2365 // propagate failure back to caller
2366 return false;
2367 }
2368 break;
2369
2370 case JVM_SIGNATURE_ARRAY:
2371 {
2372 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2373 // not enough room for a num_values field
2374 log_debug(redefine, class, annotation)("length() is too small for a num_values field");
2375 return false;
2376 }
2377
2378 // For the above tag value, value.array_value is the right union
2379 // field. This is an array of nested element_value.
2380 u2 num_values = Bytes::get_Java_u2((address)
2381 annotations_typeArray->adr_at(byte_i_ref));
2382 byte_i_ref += 2;
2383 log_debug(redefine, class, annotation)("num_values=%d", num_values);
2384
2385 int calc_num_values = 0;
2386 for (; calc_num_values < num_values; calc_num_values++) {
2387 if (!rewrite_cp_refs_in_element_value(
2388 annotations_typeArray, byte_i_ref, THREAD)) {
2389 log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values);
2390 // propagate failure back to caller
2391 return false;
2392 }
2393 }
2394 assert(num_values == calc_num_values, "sanity check");
2395 } break;
2396
2397 default:
2398 log_debug(redefine, class, annotation)("bad tag=0x%x", tag);
2399 return false;
2400 } // end decode tag field
2401
2402 return true;
2403 } // end rewrite_cp_refs_in_element_value()
2404
2405
2406 // Rewrite constant pool references in a fields_annotations field.
2407 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2408 InstanceKlass* scratch_class, TRAPS) {
2409
2410 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2411
2412 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2413 // no fields_annotations so nothing to do
2414 return true;
2415 }
2416
2417 log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length());
2418
2419 for (int i = 0; i < fields_annotations->length(); i++) {
2420 AnnotationArray* field_annotations = fields_annotations->at(i);
2421 if (field_annotations == NULL || field_annotations->length() == 0) {
2422 // this field does not have any annotations so skip it
2423 continue;
2424 }
2425
2426 int byte_i = 0; // byte index into field_annotations
2427 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2428 THREAD)) {
2429 log_debug(redefine, class, annotation)("bad field_annotations at %d", i);
2430 // propagate failure back to caller
2431 return false;
2432 }
2433 }
2434
2435 return true;
2436 } // end rewrite_cp_refs_in_fields_annotations()
2437
2438
2439 // Rewrite constant pool references in a methods_annotations field.
2440 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2441 InstanceKlass* scratch_class, TRAPS) {
2442
2443 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2444 Method* m = scratch_class->methods()->at(i);
2445 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2446
2447 if (method_annotations == NULL || method_annotations->length() == 0) {
2448 // this method does not have any annotations so skip it
2449 continue;
2450 }
2451
2452 int byte_i = 0; // byte index into method_annotations
2453 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2454 THREAD)) {
2455 log_debug(redefine, class, annotation)("bad method_annotations at %d", i);
2456 // propagate failure back to caller
2457 return false;
2458 }
2459 }
2460
2461 return true;
2462 } // end rewrite_cp_refs_in_methods_annotations()
2463
2464
2465 // Rewrite constant pool references in a methods_parameter_annotations
2466 // field. This "structure" is adapted from the
2467 // RuntimeVisibleParameterAnnotations_attribute described in section
2468 // 4.8.17 of the 2nd-edition of the VM spec:
2469 //
2470 // methods_parameter_annotations_typeArray {
2471 // u1 num_parameters;
2472 // {
2473 // u2 num_annotations;
2474 // annotation annotations[num_annotations];
2475 // } parameter_annotations[num_parameters];
2476 // }
2477 //
2478 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2479 InstanceKlass* scratch_class, TRAPS) {
2480
2481 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2482 Method* m = scratch_class->methods()->at(i);
2483 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2484 if (method_parameter_annotations == NULL
2485 || method_parameter_annotations->length() == 0) {
2486 // this method does not have any parameter annotations so skip it
2487 continue;
2488 }
2489
2490 if (method_parameter_annotations->length() < 1) {
2491 // not enough room for a num_parameters field
2492 log_debug(redefine, class, annotation)("length() is too small for a num_parameters field at %d", i);
2493 return false;
2494 }
2495
2496 int byte_i = 0; // byte index into method_parameter_annotations
2497
2498 u1 num_parameters = method_parameter_annotations->at(byte_i);
2499 byte_i++;
2500
2501 log_debug(redefine, class, annotation)("num_parameters=%d", num_parameters);
2502
2503 int calc_num_parameters = 0;
2504 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2505 if (!rewrite_cp_refs_in_annotations_typeArray(
2506 method_parameter_annotations, byte_i, THREAD)) {
2507 log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters);
2508 // propagate failure back to caller
2509 return false;
2510 }
2511 }
2512 assert(num_parameters == calc_num_parameters, "sanity check");
2513 }
2514
2515 return true;
2516 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2517
2518
2519 // Rewrite constant pool references in a methods_default_annotations
2520 // field. This "structure" is adapted from the AnnotationDefault_attribute
2521 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2522 //
2523 // methods_default_annotations_typeArray {
2524 // element_value default_value;
2525 // }
2526 //
2527 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2528 InstanceKlass* scratch_class, TRAPS) {
2529
2530 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2531 Method* m = scratch_class->methods()->at(i);
2532 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2533 if (method_default_annotations == NULL
2534 || method_default_annotations->length() == 0) {
2535 // this method does not have any default annotations so skip it
2536 continue;
2537 }
2538
2539 int byte_i = 0; // byte index into method_default_annotations
2540
2541 if (!rewrite_cp_refs_in_element_value(
2542 method_default_annotations, byte_i, THREAD)) {
2543 log_debug(redefine, class, annotation)("bad default element_value at %d", i);
2544 // propagate failure back to caller
2545 return false;
2546 }
2547 }
2548
2549 return true;
2550 } // end rewrite_cp_refs_in_methods_default_annotations()
2551
2552
2553 // Rewrite constant pool references in a class_type_annotations field.
2554 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2555 InstanceKlass* scratch_class, TRAPS) {
2556
2557 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2558 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2559 // no class_type_annotations so nothing to do
2560 return true;
2561 }
2562
2563 log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length());
2564
2565 int byte_i = 0; // byte index into class_type_annotations
2566 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2567 byte_i, "ClassFile", THREAD);
2568 } // end rewrite_cp_refs_in_class_type_annotations()
2569
2570
2571 // Rewrite constant pool references in a fields_type_annotations field.
2572 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2573 InstanceKlass* scratch_class, TRAPS) {
2574
2575 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2576 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2577 // no fields_type_annotations so nothing to do
2578 return true;
2579 }
2580
2581 log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length());
2582
2583 for (int i = 0; i < fields_type_annotations->length(); i++) {
2584 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2585 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2586 // this field does not have any annotations so skip it
2587 continue;
2588 }
2589
2590 int byte_i = 0; // byte index into field_type_annotations
2591 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2592 byte_i, "field_info", THREAD)) {
2593 log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i);
2594 // propagate failure back to caller
2595 return false;
2596 }
2597 }
2598
2599 return true;
2600 } // end rewrite_cp_refs_in_fields_type_annotations()
2601
2602
2603 // Rewrite constant pool references in a methods_type_annotations field.
2604 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2605 InstanceKlass* scratch_class, TRAPS) {
2606
2607 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2608 Method* m = scratch_class->methods()->at(i);
2609 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2610
2611 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2612 // this method does not have any annotations so skip it
2613 continue;
2614 }
2615
2616 log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length());
2617
2618 int byte_i = 0; // byte index into method_type_annotations
2619 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2620 byte_i, "method_info", THREAD)) {
2621 log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i);
2622 // propagate failure back to caller
2623 return false;
2624 }
2625 }
2626
2627 return true;
2628 } // end rewrite_cp_refs_in_methods_type_annotations()
2629
2630
2631 // Rewrite constant pool references in a type_annotations
2632 // field. This "structure" is adapted from the
2633 // RuntimeVisibleTypeAnnotations_attribute described in
2634 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2635 //
2636 // type_annotations_typeArray {
2637 // u2 num_annotations;
2638 // type_annotation annotations[num_annotations];
2639 // }
2640 //
2641 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2642 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2643 const char * location_mesg, TRAPS) {
2644
2645 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2646 // not enough room for num_annotations field
2647 log_debug(redefine, class, annotation)("length() is too small for num_annotations field");
2648 return false;
2649 }
2650
2651 u2 num_annotations = Bytes::get_Java_u2((address)
2652 type_annotations_typeArray->adr_at(byte_i_ref));
2653 byte_i_ref += 2;
2654
2655 log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations);
2656
2657 int calc_num_annotations = 0;
2658 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2659 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2660 byte_i_ref, location_mesg, THREAD)) {
2661 log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations);
2662 // propagate failure back to caller
2663 return false;
2664 }
2665 }
2666 assert(num_annotations == calc_num_annotations, "sanity check");
2667
2668 if (byte_i_ref != type_annotations_typeArray->length()) {
2669 log_debug(redefine, class, annotation)
2670 ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)",
2671 byte_i_ref, type_annotations_typeArray->length());
2672 return false;
2673 }
2674
2675 return true;
2676 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2677
2678
2679 // Rewrite constant pool references in a type_annotation
2680 // field. This "structure" is adapted from the
2681 // RuntimeVisibleTypeAnnotations_attribute described in
2682 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2683 //
2684 // type_annotation {
2685 // u1 target_type;
2686 // union {
2687 // type_parameter_target;
2688 // supertype_target;
2689 // type_parameter_bound_target;
2690 // empty_target;
2691 // method_formal_parameter_target;
2692 // throws_target;
2693 // localvar_target;
2694 // catch_target;
2695 // offset_target;
2696 // type_argument_target;
2697 // } target_info;
2698 // type_path target_path;
2699 // annotation anno;
2700 // }
2701 //
2702 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2703 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2704 const char * location_mesg, TRAPS) {
2705
2706 if (!skip_type_annotation_target(type_annotations_typeArray,
2707 byte_i_ref, location_mesg, THREAD)) {
2708 return false;
2709 }
2710
2711 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2712 byte_i_ref, THREAD)) {
2713 return false;
2714 }
2715
2716 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2717 byte_i_ref, THREAD)) {
2718 return false;
2719 }
2720
2721 return true;
2722 } // end rewrite_cp_refs_in_type_annotation_struct()
2723
2724
2725 // Read, verify and skip over the target_type and target_info part
2726 // so that rewriting can continue in the later parts of the struct.
2727 //
2728 // u1 target_type;
2729 // union {
2730 // type_parameter_target;
2731 // supertype_target;
2732 // type_parameter_bound_target;
2733 // empty_target;
2734 // method_formal_parameter_target;
2735 // throws_target;
2736 // localvar_target;
2737 // catch_target;
2738 // offset_target;
2739 // type_argument_target;
2740 // } target_info;
2741 //
2742 bool VM_RedefineClasses::skip_type_annotation_target(
2743 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2744 const char * location_mesg, TRAPS) {
2745
2746 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2747 // not enough room for a target_type let alone the rest of a type_annotation
2748 log_debug(redefine, class, annotation)("length() is too small for a target_type");
2749 return false;
2750 }
2751
2752 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2753 byte_i_ref += 1;
2754 log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type);
2755 log_debug(redefine, class, annotation)("location=%s", location_mesg);
2756
2757 // Skip over target_info
2758 switch (target_type) {
2759 case 0x00:
2760 // kind: type parameter declaration of generic class or interface
2761 // location: ClassFile
2762 case 0x01:
2763 // kind: type parameter declaration of generic method or constructor
2764 // location: method_info
2765
2766 {
2767 // struct:
2768 // type_parameter_target {
2769 // u1 type_parameter_index;
2770 // }
2771 //
2772 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2773 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target");
2774 return false;
2775 }
2776
2777 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2778 byte_i_ref += 1;
2779
2780 log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index);
2781 } break;
2782
2783 case 0x10:
2784 // kind: type in extends clause of class or interface declaration
2785 // (including the direct superclass of an unsafe anonymous class declaration),
2786 // or in implements clause of interface declaration
2787 // location: ClassFile
2788
2789 {
2790 // struct:
2791 // supertype_target {
2792 // u2 supertype_index;
2793 // }
2794 //
2795 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2796 log_debug(redefine, class, annotation)("length() is too small for a supertype_target");
2797 return false;
2798 }
2799
2800 u2 supertype_index = Bytes::get_Java_u2((address)
2801 type_annotations_typeArray->adr_at(byte_i_ref));
2802 byte_i_ref += 2;
2803
2804 log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index);
2805 } break;
2806
2807 case 0x11:
2808 // kind: type in bound of type parameter declaration of generic class or interface
2809 // location: ClassFile
2810 case 0x12:
2811 // kind: type in bound of type parameter declaration of generic method or constructor
2812 // location: method_info
2813
2814 {
2815 // struct:
2816 // type_parameter_bound_target {
2817 // u1 type_parameter_index;
2818 // u1 bound_index;
2819 // }
2820 //
2821 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2822 log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target");
2823 return false;
2824 }
2825
2826 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2827 byte_i_ref += 1;
2828 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2829 byte_i_ref += 1;
2830
2831 log_debug(redefine, class, annotation)
2832 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index);
2833 } break;
2834
2835 case 0x13:
2836 // kind: type in field declaration
2837 // location: field_info
2838 case 0x14:
2839 // kind: return type of method, or type of newly constructed object
2840 // location: method_info
2841 case 0x15:
2842 // kind: receiver type of method or constructor
2843 // location: method_info
2844
2845 {
2846 // struct:
2847 // empty_target {
2848 // }
2849 //
2850 log_debug(redefine, class, annotation)("empty_target");
2851 } break;
2852
2853 case 0x16:
2854 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2855 // location: method_info
2856
2857 {
2858 // struct:
2859 // formal_parameter_target {
2860 // u1 formal_parameter_index;
2861 // }
2862 //
2863 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2864 log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target");
2865 return false;
2866 }
2867
2868 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2869 byte_i_ref += 1;
2870
2871 log_debug(redefine, class, annotation)
2872 ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index);
2873 } break;
2874
2875 case 0x17:
2876 // kind: type in throws clause of method or constructor
2877 // location: method_info
2878
2879 {
2880 // struct:
2881 // throws_target {
2882 // u2 throws_type_index
2883 // }
2884 //
2885 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2886 log_debug(redefine, class, annotation)("length() is too small for a throws_target");
2887 return false;
2888 }
2889
2890 u2 throws_type_index = Bytes::get_Java_u2((address)
2891 type_annotations_typeArray->adr_at(byte_i_ref));
2892 byte_i_ref += 2;
2893
2894 log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index);
2895 } break;
2896
2897 case 0x40:
2898 // kind: type in local variable declaration
2899 // location: Code
2900 case 0x41:
2901 // kind: type in resource variable declaration
2902 // location: Code
2903
2904 {
2905 // struct:
2906 // localvar_target {
2907 // u2 table_length;
2908 // struct {
2909 // u2 start_pc;
2910 // u2 length;
2911 // u2 index;
2912 // } table[table_length];
2913 // }
2914 //
2915 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2916 // not enough room for a table_length let alone the rest of a localvar_target
2917 log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length");
2918 return false;
2919 }
2920
2921 u2 table_length = Bytes::get_Java_u2((address)
2922 type_annotations_typeArray->adr_at(byte_i_ref));
2923 byte_i_ref += 2;
2924
2925 log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length);
2926
2927 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2928 int table_size = table_length * table_struct_size;
2929
2930 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2931 // not enough room for a table
2932 log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length);
2933 return false;
2934 }
2935
2936 // Skip over table
2937 byte_i_ref += table_size;
2938 } break;
2939
2940 case 0x42:
2941 // kind: type in exception parameter declaration
2942 // location: Code
2943
2944 {
2945 // struct:
2946 // catch_target {
2947 // u2 exception_table_index;
2948 // }
2949 //
2950 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2951 log_debug(redefine, class, annotation)("length() is too small for a catch_target");
2952 return false;
2953 }
2954
2955 u2 exception_table_index = Bytes::get_Java_u2((address)
2956 type_annotations_typeArray->adr_at(byte_i_ref));
2957 byte_i_ref += 2;
2958
2959 log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index);
2960 } break;
2961
2962 case 0x43:
2963 // kind: type in instanceof expression
2964 // location: Code
2965 case 0x44:
2966 // kind: type in new expression
2967 // location: Code
2968 case 0x45:
2969 // kind: type in method reference expression using ::new
2970 // location: Code
2971 case 0x46:
2972 // kind: type in method reference expression using ::Identifier
2973 // location: Code
2974
2975 {
2976 // struct:
2977 // offset_target {
2978 // u2 offset;
2979 // }
2980 //
2981 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2982 log_debug(redefine, class, annotation)("length() is too small for a offset_target");
2983 return false;
2984 }
2985
2986 u2 offset = Bytes::get_Java_u2((address)
2987 type_annotations_typeArray->adr_at(byte_i_ref));
2988 byte_i_ref += 2;
2989
2990 log_debug(redefine, class, annotation)("offset_target: offset=%d", offset);
2991 } break;
2992
2993 case 0x47:
2994 // kind: type in cast expression
2995 // location: Code
2996 case 0x48:
2997 // kind: type argument for generic constructor in new expression or
2998 // explicit constructor invocation statement
2999 // location: Code
3000 case 0x49:
3001 // kind: type argument for generic method in method invocation expression
3002 // location: Code
3003 case 0x4A:
3004 // kind: type argument for generic constructor in method reference expression using ::new
3005 // location: Code
3006 case 0x4B:
3007 // kind: type argument for generic method in method reference expression using ::Identifier
3008 // location: Code
3009
3010 {
3011 // struct:
3012 // type_argument_target {
3013 // u2 offset;
3014 // u1 type_argument_index;
3015 // }
3016 //
3017 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
3018 log_debug(redefine, class, annotation)("length() is too small for a type_argument_target");
3019 return false;
3020 }
3021
3022 u2 offset = Bytes::get_Java_u2((address)
3023 type_annotations_typeArray->adr_at(byte_i_ref));
3024 byte_i_ref += 2;
3025 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3026 byte_i_ref += 1;
3027
3028 log_debug(redefine, class, annotation)
3029 ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index);
3030 } break;
3031
3032 default:
3033 log_debug(redefine, class, annotation)("unknown target_type");
3034 #ifdef ASSERT
3035 ShouldNotReachHere();
3036 #endif
3037 return false;
3038 }
3039
3040 return true;
3041 } // end skip_type_annotation_target()
3042
3043
3044 // Read, verify and skip over the type_path part so that rewriting
3045 // can continue in the later parts of the struct.
3046 //
3047 // type_path {
3048 // u1 path_length;
3049 // {
3050 // u1 type_path_kind;
3051 // u1 type_argument_index;
3052 // } path[path_length];
3053 // }
3054 //
3055 bool VM_RedefineClasses::skip_type_annotation_type_path(
3056 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
3057
3058 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
3059 // not enough room for a path_length let alone the rest of the type_path
3060 log_debug(redefine, class, annotation)("length() is too small for a type_path");
3061 return false;
3062 }
3063
3064 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
3065 byte_i_ref += 1;
3066
3067 log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length);
3068
3069 int calc_path_length = 0;
3070 for (; calc_path_length < path_length; calc_path_length++) {
3071 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
3072 // not enough room for a path
3073 log_debug(redefine, class, annotation)
3074 ("length() is too small for path entry %d of %d", calc_path_length, path_length);
3075 return false;
3076 }
3077
3078 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
3079 byte_i_ref += 1;
3080 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
3081 byte_i_ref += 1;
3082
3083 log_debug(redefine, class, annotation)
3084 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
3085 calc_path_length, type_path_kind, type_argument_index);
3086
3087 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
3088 // not enough room for a path
3089 log_debug(redefine, class, annotation)("inconsistent type_path values");
3090 return false;
3091 }
3092 }
3093 assert(path_length == calc_path_length, "sanity check");
3094
3095 return true;
3096 } // end skip_type_annotation_type_path()
3097
3098
3099 // Rewrite constant pool references in the method's stackmap table.
3100 // These "structures" are adapted from the StackMapTable_attribute that
3101 // is described in section 4.8.4 of the 6.0 version of the VM spec
3102 // (dated 2005.10.26):
3103 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3104 //
3105 // stack_map {
3106 // u2 number_of_entries;
3107 // stack_map_frame entries[number_of_entries];
3108 // }
3109 //
3110 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
3111 const methodHandle& method, TRAPS) {
3112
3113 if (!method->has_stackmap_table()) {
3114 return;
3115 }
3116
3117 AnnotationArray* stackmap_data = method->stackmap_data();
3118 address stackmap_p = (address)stackmap_data->adr_at(0);
3119 address stackmap_end = stackmap_p + stackmap_data->length();
3120
3121 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
3122 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
3123 stackmap_p += 2;
3124
3125 log_debug(redefine, class, stackmap)("number_of_entries=%u", number_of_entries);
3126
3127 // walk through each stack_map_frame
3128 u2 calc_number_of_entries = 0;
3129 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
3130 // The stack_map_frame structure is a u1 frame_type followed by
3131 // 0 or more bytes of data:
3132 //
3133 // union stack_map_frame {
3134 // same_frame;
3135 // same_locals_1_stack_item_frame;
3136 // same_locals_1_stack_item_frame_extended;
3137 // chop_frame;
3138 // same_frame_extended;
3139 // append_frame;
3140 // full_frame;
3141 // }
3142
3143 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
3144 u1 frame_type = *stackmap_p;
3145 stackmap_p++;
3146
3147 // same_frame {
3148 // u1 frame_type = SAME; /* 0-63 */
3149 // }
3150 if (frame_type <= 63) {
3151 // nothing more to do for same_frame
3152 }
3153
3154 // same_locals_1_stack_item_frame {
3155 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
3156 // verification_type_info stack[1];
3157 // }
3158 else if (frame_type >= 64 && frame_type <= 127) {
3159 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3160 calc_number_of_entries, frame_type, THREAD);
3161 }
3162
3163 // reserved for future use
3164 else if (frame_type >= 128 && frame_type <= 246) {
3165 // nothing more to do for reserved frame_types
3166 }
3167
3168 // same_locals_1_stack_item_frame_extended {
3169 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
3170 // u2 offset_delta;
3171 // verification_type_info stack[1];
3172 // }
3173 else if (frame_type == 247) {
3174 stackmap_p += 2;
3175 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3176 calc_number_of_entries, frame_type, THREAD);
3177 }
3178
3179 // chop_frame {
3180 // u1 frame_type = CHOP; /* 248-250 */
3181 // u2 offset_delta;
3182 // }
3183 else if (frame_type >= 248 && frame_type <= 250) {
3184 stackmap_p += 2;
3185 }
3186
3187 // same_frame_extended {
3188 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
3189 // u2 offset_delta;
3190 // }
3191 else if (frame_type == 251) {
3192 stackmap_p += 2;
3193 }
3194
3195 // append_frame {
3196 // u1 frame_type = APPEND; /* 252-254 */
3197 // u2 offset_delta;
3198 // verification_type_info locals[frame_type - 251];
3199 // }
3200 else if (frame_type >= 252 && frame_type <= 254) {
3201 assert(stackmap_p + 2 <= stackmap_end,
3202 "no room for offset_delta");
3203 stackmap_p += 2;
3204 u1 len = frame_type - 251;
3205 for (u1 i = 0; i < len; i++) {
3206 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3207 calc_number_of_entries, frame_type, THREAD);
3208 }
3209 }
3210
3211 // full_frame {
3212 // u1 frame_type = FULL_FRAME; /* 255 */
3213 // u2 offset_delta;
3214 // u2 number_of_locals;
3215 // verification_type_info locals[number_of_locals];
3216 // u2 number_of_stack_items;
3217 // verification_type_info stack[number_of_stack_items];
3218 // }
3219 else if (frame_type == 255) {
3220 assert(stackmap_p + 2 + 2 <= stackmap_end,
3221 "no room for smallest full_frame");
3222 stackmap_p += 2;
3223
3224 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3225 stackmap_p += 2;
3226
3227 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3228 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3229 calc_number_of_entries, frame_type, THREAD);
3230 }
3231
3232 // Use the largest size for the number_of_stack_items, but only get
3233 // the right number of bytes.
3234 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3235 stackmap_p += 2;
3236
3237 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3238 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3239 calc_number_of_entries, frame_type, THREAD);
3240 }
3241 }
3242 } // end while there is a stack_map_frame
3243 assert(number_of_entries == calc_number_of_entries, "sanity check");
3244 } // end rewrite_cp_refs_in_stack_map_table()
3245
3246
3247 // Rewrite constant pool references in the verification type info
3248 // portion of the method's stackmap table. These "structures" are
3249 // adapted from the StackMapTable_attribute that is described in
3250 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3251 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3252 //
3253 // The verification_type_info structure is a u1 tag followed by 0 or
3254 // more bytes of data:
3255 //
3256 // union verification_type_info {
3257 // Top_variable_info;
3258 // Integer_variable_info;
3259 // Float_variable_info;
3260 // Long_variable_info;
3261 // Double_variable_info;
3262 // Null_variable_info;
3263 // UninitializedThis_variable_info;
3264 // Object_variable_info;
3265 // Uninitialized_variable_info;
3266 // }
3267 //
3268 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3269 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3270 u1 frame_type, TRAPS) {
3271
3272 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3273 u1 tag = *stackmap_p_ref;
3274 stackmap_p_ref++;
3275
3276 switch (tag) {
3277 // Top_variable_info {
3278 // u1 tag = ITEM_Top; /* 0 */
3279 // }
3280 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3281 case 0: // fall through
3282
3283 // Integer_variable_info {
3284 // u1 tag = ITEM_Integer; /* 1 */
3285 // }
3286 case ITEM_Integer: // fall through
3287
3288 // Float_variable_info {
3289 // u1 tag = ITEM_Float; /* 2 */
3290 // }
3291 case ITEM_Float: // fall through
3292
3293 // Double_variable_info {
3294 // u1 tag = ITEM_Double; /* 3 */
3295 // }
3296 case ITEM_Double: // fall through
3297
3298 // Long_variable_info {
3299 // u1 tag = ITEM_Long; /* 4 */
3300 // }
3301 case ITEM_Long: // fall through
3302
3303 // Null_variable_info {
3304 // u1 tag = ITEM_Null; /* 5 */
3305 // }
3306 case ITEM_Null: // fall through
3307
3308 // UninitializedThis_variable_info {
3309 // u1 tag = ITEM_UninitializedThis; /* 6 */
3310 // }
3311 case ITEM_UninitializedThis:
3312 // nothing more to do for the above tag types
3313 break;
3314
3315 // Object_variable_info {
3316 // u1 tag = ITEM_Object; /* 7 */
3317 // u2 cpool_index;
3318 // }
3319 case ITEM_Object:
3320 {
3321 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3322 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3323 u2 new_cp_index = find_new_index(cpool_index);
3324 if (new_cp_index != 0) {
3325 log_debug(redefine, class, stackmap)("mapped old cpool_index=%d", cpool_index);
3326 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3327 cpool_index = new_cp_index;
3328 }
3329 stackmap_p_ref += 2;
3330
3331 log_debug(redefine, class, stackmap)
3332 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, frame_type, cpool_index);
3333 } break;
3334
3335 // Uninitialized_variable_info {
3336 // u1 tag = ITEM_Uninitialized; /* 8 */
3337 // u2 offset;
3338 // }
3339 case ITEM_Uninitialized:
3340 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3341 stackmap_p_ref += 2;
3342 break;
3343
3344 default:
3345 log_debug(redefine, class, stackmap)("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag);
3346 ShouldNotReachHere();
3347 break;
3348 } // end switch (tag)
3349 } // end rewrite_cp_refs_in_verification_type_info()
3350
3351
3352 // Change the constant pool associated with klass scratch_class to
3353 // scratch_cp. If shrink is true, then scratch_cp_length elements
3354 // are copied from scratch_cp to a smaller constant pool and the
3355 // smaller constant pool is associated with scratch_class.
3356 void VM_RedefineClasses::set_new_constant_pool(
3357 ClassLoaderData* loader_data,
3358 InstanceKlass* scratch_class, constantPoolHandle scratch_cp,
3359 int scratch_cp_length, TRAPS) {
3360 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3361
3362 // scratch_cp is a merged constant pool and has enough space for a
3363 // worst case merge situation. We want to associate the minimum
3364 // sized constant pool with the klass to save space.
3365 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3366 constantPoolHandle smaller_cp(THREAD, cp);
3367
3368 // preserve version() value in the smaller copy
3369 int version = scratch_cp->version();
3370 assert(version != 0, "sanity check");
3371 smaller_cp->set_version(version);
3372
3373 // attach klass to new constant pool
3374 // reference to the cp holder is needed for copy_operands()
3375 smaller_cp->set_pool_holder(scratch_class);
3376
3377 if (scratch_cp->has_dynamic_constant()) {
3378 smaller_cp->set_has_dynamic_constant();
3379 }
3380
3381 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3382 if (HAS_PENDING_EXCEPTION) {
3383 // Exception is handled in the caller
3384 loader_data->add_to_deallocate_list(smaller_cp());
3385 return;
3386 }
3387 scratch_cp = smaller_cp;
3388
3389 // attach new constant pool to klass
3390 scratch_class->set_constants(scratch_cp());
3391 scratch_cp->initialize_unresolved_klasses(loader_data, CHECK);
3392
3393 int i; // for portability
3394
3395 // update each field in klass to use new constant pool indices as needed
3396 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3397 jshort cur_index = fs.name_index();
3398 jshort new_index = find_new_index(cur_index);
3399 if (new_index != 0) {
3400 log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index);
3401 fs.set_name_index(new_index);
3402 }
3403 cur_index = fs.signature_index();
3404 new_index = find_new_index(cur_index);
3405 if (new_index != 0) {
3406 log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index);
3407 fs.set_signature_index(new_index);
3408 }
3409 cur_index = fs.initval_index();
3410 new_index = find_new_index(cur_index);
3411 if (new_index != 0) {
3412 log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index);
3413 fs.set_initval_index(new_index);
3414 }
3415 cur_index = fs.generic_signature_index();
3416 new_index = find_new_index(cur_index);
3417 if (new_index != 0) {
3418 log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index);
3419 fs.set_generic_signature_index(new_index);
3420 }
3421 } // end for each field
3422
3423 // Update constant pool indices in the inner classes info to use
3424 // new constant indices as needed. The inner classes info is a
3425 // quadruple:
3426 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3427 InnerClassesIterator iter(scratch_class);
3428 for (; !iter.done(); iter.next()) {
3429 int cur_index = iter.inner_class_info_index();
3430 if (cur_index == 0) {
3431 continue; // JVM spec. allows null inner class refs so skip it
3432 }
3433 int new_index = find_new_index(cur_index);
3434 if (new_index != 0) {
3435 log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index);
3436 iter.set_inner_class_info_index(new_index);
3437 }
3438 cur_index = iter.outer_class_info_index();
3439 new_index = find_new_index(cur_index);
3440 if (new_index != 0) {
3441 log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index);
3442 iter.set_outer_class_info_index(new_index);
3443 }
3444 cur_index = iter.inner_name_index();
3445 new_index = find_new_index(cur_index);
3446 if (new_index != 0) {
3447 log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index);
3448 iter.set_inner_name_index(new_index);
3449 }
3450 } // end for each inner class
3451
3452 // Attach each method in klass to the new constant pool and update
3453 // to use new constant pool indices as needed:
3454 Array<Method*>* methods = scratch_class->methods();
3455 for (i = methods->length() - 1; i >= 0; i--) {
3456 methodHandle method(THREAD, methods->at(i));
3457 method->set_constants(scratch_cp());
3458
3459 int new_index = find_new_index(method->name_index());
3460 if (new_index != 0) {
3461 log_trace(redefine, class, constantpool)
3462 ("method-name_index change: %d to %d", method->name_index(), new_index);
3463 method->set_name_index(new_index);
3464 }
3465 new_index = find_new_index(method->signature_index());
3466 if (new_index != 0) {
3467 log_trace(redefine, class, constantpool)
3468 ("method-signature_index change: %d to %d", method->signature_index(), new_index);
3469 method->set_signature_index(new_index);
3470 }
3471 new_index = find_new_index(method->generic_signature_index());
3472 if (new_index != 0) {
3473 log_trace(redefine, class, constantpool)
3474 ("method-generic_signature_index change: %d to %d", method->generic_signature_index(), new_index);
3475 method->set_generic_signature_index(new_index);
3476 }
3477
3478 // Update constant pool indices in the method's checked exception
3479 // table to use new constant indices as needed.
3480 int cext_length = method->checked_exceptions_length();
3481 if (cext_length > 0) {
3482 CheckedExceptionElement * cext_table =
3483 method->checked_exceptions_start();
3484 for (int j = 0; j < cext_length; j++) {
3485 int cur_index = cext_table[j].class_cp_index;
3486 int new_index = find_new_index(cur_index);
3487 if (new_index != 0) {
3488 log_trace(redefine, class, constantpool)("cext-class_cp_index change: %d to %d", cur_index, new_index);
3489 cext_table[j].class_cp_index = (u2)new_index;
3490 }
3491 } // end for each checked exception table entry
3492 } // end if there are checked exception table entries
3493
3494 // Update each catch type index in the method's exception table
3495 // to use new constant pool indices as needed. The exception table
3496 // holds quadruple entries of the form:
3497 // (beg_bci, end_bci, handler_bci, klass_index)
3498
3499 ExceptionTable ex_table(method());
3500 int ext_length = ex_table.length();
3501
3502 for (int j = 0; j < ext_length; j ++) {
3503 int cur_index = ex_table.catch_type_index(j);
3504 int new_index = find_new_index(cur_index);
3505 if (new_index != 0) {
3506 log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index);
3507 ex_table.set_catch_type_index(j, new_index);
3508 }
3509 } // end for each exception table entry
3510
3511 // Update constant pool indices in the method's local variable
3512 // table to use new constant indices as needed. The local variable
3513 // table hold sextuple entries of the form:
3514 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3515 int lvt_length = method->localvariable_table_length();
3516 if (lvt_length > 0) {
3517 LocalVariableTableElement * lv_table =
3518 method->localvariable_table_start();
3519 for (int j = 0; j < lvt_length; j++) {
3520 int cur_index = lv_table[j].name_cp_index;
3521 int new_index = find_new_index(cur_index);
3522 if (new_index != 0) {
3523 log_trace(redefine, class, constantpool)("lvt-name_cp_index change: %d to %d", cur_index, new_index);
3524 lv_table[j].name_cp_index = (u2)new_index;
3525 }
3526 cur_index = lv_table[j].descriptor_cp_index;
3527 new_index = find_new_index(cur_index);
3528 if (new_index != 0) {
3529 log_trace(redefine, class, constantpool)("lvt-descriptor_cp_index change: %d to %d", cur_index, new_index);
3530 lv_table[j].descriptor_cp_index = (u2)new_index;
3531 }
3532 cur_index = lv_table[j].signature_cp_index;
3533 new_index = find_new_index(cur_index);
3534 if (new_index != 0) {
3535 log_trace(redefine, class, constantpool)("lvt-signature_cp_index change: %d to %d", cur_index, new_index);
3536 lv_table[j].signature_cp_index = (u2)new_index;
3537 }
3538 } // end for each local variable table entry
3539 } // end if there are local variable table entries
3540
3541 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3542 } // end for each method
3543 } // end set_new_constant_pool()
3544
3545
3546 // Unevolving classes may point to methods of the_class directly
3547 // from their constant pool caches, itables, and/or vtables. We
3548 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3549 // to fix up these pointers. MethodData also points to old methods and
3550 // must be cleaned.
3551
3552 // Adjust cpools and vtables closure
3553 void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
3554
3555 // This is a very busy routine. We don't want too much tracing
3556 // printed out.
3557 bool trace_name_printed = false;
3558
3559 // If the class being redefined is java.lang.Object, we need to fix all
3560 // array class vtables also
3561 if (k->is_array_klass() && _has_redefined_Object) {
3562 k->vtable().adjust_method_entries(&trace_name_printed);
3563
3564 } else if (k->is_instance_klass()) {
3565 HandleMark hm(_thread);
3566 InstanceKlass *ik = InstanceKlass::cast(k);
3567
3568 // Clean MethodData of this class's methods so they don't refer to
3569 // old methods that are no longer running.
3570 Array<Method*>* methods = ik->methods();
3571 int num_methods = methods->length();
3572 for (int index = 0; index < num_methods; ++index) {
3573 if (methods->at(index)->method_data() != NULL) {
3574 methods->at(index)->method_data()->clean_weak_method_links();
3575 }
3576 }
3577
3578 // HotSpot specific optimization! HotSpot does not currently
3579 // support delegation from the bootstrap class loader to a
3580 // user-defined class loader. This means that if the bootstrap
3581 // class loader is the initiating class loader, then it will also
3582 // be the defining class loader. This also means that classes
3583 // loaded by the bootstrap class loader cannot refer to classes
3584 // loaded by a user-defined class loader. Note: a user-defined
3585 // class loader can delegate to the bootstrap class loader.
3586 //
3587 // If the current class being redefined has a user-defined class
3588 // loader as its defining class loader, then we can skip all
3589 // classes loaded by the bootstrap class loader.
3590 if (!_has_null_class_loader && ik->class_loader() == NULL) {
3591 return;
3592 }
3593
3594 // Adjust all vtables, default methods and itables, to clean out old methods.
3595 ResourceMark rm(_thread);
3596 if (ik->vtable_length() > 0) {
3597 ik->vtable().adjust_method_entries(&trace_name_printed);
3598 ik->adjust_default_methods(&trace_name_printed);
3599 }
3600
3601 if (ik->itable_length() > 0) {
3602 ik->itable().adjust_method_entries(&trace_name_printed);
3603 }
3604
3605 // The constant pools in other classes (other_cp) can refer to
3606 // old methods. We have to update method information in
3607 // other_cp's cache. If other_cp has a previous version, then we
3608 // have to repeat the process for each previous version. The
3609 // constant pool cache holds the Method*s for non-virtual
3610 // methods and for virtual, final methods.
3611 //
3612 // Special case: if the current class being redefined, then new_cp
3613 // has already been attached to the_class and old_cp has already
3614 // been added as a previous version. The new_cp doesn't have any
3615 // cached references to old methods so it doesn't need to be
3616 // updated. We can simply start with the previous version(s) in
3617 // that case.
3618 ConstantPoolCache* cp_cache;
3619
3620 if (!ik->is_being_redefined()) {
3621 // this klass' constant pool cache may need adjustment
3622 ConstantPool* other_cp = ik->constants();
3623 cp_cache = other_cp->cache();
3624 if (cp_cache != NULL) {
3625 cp_cache->adjust_method_entries(&trace_name_printed);
3626 }
3627 }
3628
3629 // the previous versions' constant pool caches may need adjustment
3630 for (InstanceKlass* pv_node = ik->previous_versions();
3631 pv_node != NULL;
3632 pv_node = pv_node->previous_versions()) {
3633 cp_cache = pv_node->constants()->cache();
3634 if (cp_cache != NULL) {
3635 cp_cache->adjust_method_entries(&trace_name_printed);
3636 }
3637 }
3638 }
3639 }
3640
3641 void VM_RedefineClasses::update_jmethod_ids(Thread* thread) {
3642 for (int j = 0; j < _matching_methods_length; ++j) {
3643 Method* old_method = _matching_old_methods[j];
3644 jmethodID jmid = old_method->find_jmethod_id_or_null();
3645 if (jmid != NULL) {
3646 // There is a jmethodID, change it to point to the new method
3647 methodHandle new_method_h(thread, _matching_new_methods[j]);
3648 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3649 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3650 "should be replaced");
3651 }
3652 }
3653 }
3654
3655 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3656 int emcp_method_count = 0;
3657 int obsolete_count = 0;
3658 int old_index = 0;
3659 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3660 Method* old_method = _matching_old_methods[j];
3661 Method* new_method = _matching_new_methods[j];
3662 Method* old_array_method;
3663
3664 // Maintain an old_index into the _old_methods array by skipping
3665 // deleted methods
3666 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3667 ++old_index;
3668 }
3669
3670 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3671 // The EMCP definition from JSR-163 requires the bytecodes to be
3672 // the same with the exception of constant pool indices which may
3673 // differ. However, the constants referred to by those indices
3674 // must be the same.
3675 //
3676 // We use methods_EMCP() for comparison since constant pool
3677 // merging can remove duplicate constant pool entries that were
3678 // present in the old method and removed from the rewritten new
3679 // method. A faster binary comparison function would consider the
3680 // old and new methods to be different when they are actually
3681 // EMCP.
3682 //
3683 // The old and new methods are EMCP and you would think that we
3684 // could get rid of one of them here and now and save some space.
3685 // However, the concept of EMCP only considers the bytecodes and
3686 // the constant pool entries in the comparison. Other things,
3687 // e.g., the line number table (LNT) or the local variable table
3688 // (LVT) don't count in the comparison. So the new (and EMCP)
3689 // method can have a new LNT that we need so we can't just
3690 // overwrite the new method with the old method.
3691 //
3692 // When this routine is called, we have already attached the new
3693 // methods to the_class so the old methods are effectively
3694 // overwritten. However, if an old method is still executing,
3695 // then the old method cannot be collected until sometime after
3696 // the old method call has returned. So the overwriting of old
3697 // methods by new methods will save us space except for those
3698 // (hopefully few) old methods that are still executing.
3699 //
3700 // A method refers to a ConstMethod* and this presents another
3701 // possible avenue to space savings. The ConstMethod* in the
3702 // new method contains possibly new attributes (LNT, LVT, etc).
3703 // At first glance, it seems possible to save space by replacing
3704 // the ConstMethod* in the old method with the ConstMethod*
3705 // from the new method. The old and new methods would share the
3706 // same ConstMethod* and we would save the space occupied by
3707 // the old ConstMethod*. However, the ConstMethod* contains
3708 // a back reference to the containing method. Sharing the
3709 // ConstMethod* between two methods could lead to confusion in
3710 // the code that uses the back reference. This would lead to
3711 // brittle code that could be broken in non-obvious ways now or
3712 // in the future.
3713 //
3714 // Another possibility is to copy the ConstMethod* from the new
3715 // method to the old method and then overwrite the new method with
3716 // the old method. Since the ConstMethod* contains the bytecodes
3717 // for the method embedded in the oop, this option would change
3718 // the bytecodes out from under any threads executing the old
3719 // method and make the thread's bcp invalid. Since EMCP requires
3720 // that the bytecodes be the same modulo constant pool indices, it
3721 // is straight forward to compute the correct new bcp in the new
3722 // ConstMethod* from the old bcp in the old ConstMethod*. The
3723 // time consuming part would be searching all the frames in all
3724 // of the threads to find all of the calls to the old method.
3725 //
3726 // It looks like we will have to live with the limited savings
3727 // that we get from effectively overwriting the old methods
3728 // when the new methods are attached to the_class.
3729
3730 // Count number of methods that are EMCP. The method will be marked
3731 // old but not obsolete if it is EMCP.
3732 emcp_method_count++;
3733
3734 // An EMCP method is _not_ obsolete. An obsolete method has a
3735 // different jmethodID than the current method. An EMCP method
3736 // has the same jmethodID as the current method. Having the
3737 // same jmethodID for all EMCP versions of a method allows for
3738 // a consistent view of the EMCP methods regardless of which
3739 // EMCP method you happen to have in hand. For example, a
3740 // breakpoint set in one EMCP method will work for all EMCP
3741 // versions of the method including the current one.
3742 } else {
3743 // mark obsolete methods as such
3744 old_method->set_is_obsolete();
3745 obsolete_count++;
3746
3747 // obsolete methods need a unique idnum so they become new entries in
3748 // the jmethodID cache in InstanceKlass
3749 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3750 u2 num = InstanceKlass::cast(_the_class)->next_method_idnum();
3751 if (num != ConstMethod::UNSET_IDNUM) {
3752 old_method->set_method_idnum(num);
3753 }
3754
3755 // With tracing we try not to "yack" too much. The position of
3756 // this trace assumes there are fewer obsolete methods than
3757 // EMCP methods.
3758 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3759 ResourceMark rm;
3760 log_trace(redefine, class, obsolete, mark)
3761 ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3762 }
3763 }
3764 old_method->set_is_old();
3765 }
3766 for (int i = 0; i < _deleted_methods_length; ++i) {
3767 Method* old_method = _deleted_methods[i];
3768
3769 assert(!old_method->has_vtable_index(),
3770 "cannot delete methods with vtable entries");;
3771
3772 // Mark all deleted methods as old, obsolete and deleted
3773 old_method->set_is_deleted();
3774 old_method->set_is_old();
3775 old_method->set_is_obsolete();
3776 ++obsolete_count;
3777 // With tracing we try not to "yack" too much. The position of
3778 // this trace assumes there are fewer obsolete methods than
3779 // EMCP methods.
3780 if (log_is_enabled(Trace, redefine, class, obsolete, mark)) {
3781 ResourceMark rm;
3782 log_trace(redefine, class, obsolete, mark)
3783 ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string());
3784 }
3785 }
3786 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3787 "sanity check");
3788 log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count);
3789 return emcp_method_count;
3790 }
3791
3792 // This internal class transfers the native function registration from old methods
3793 // to new methods. It is designed to handle both the simple case of unchanged
3794 // native methods and the complex cases of native method prefixes being added and/or
3795 // removed.
3796 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3797 //
3798 // This class is used after the new methods have been installed in "the_class".
3799 //
3800 // So, for example, the following must be handled. Where 'm' is a method and
3801 // a number followed by an underscore is a prefix.
3802 //
3803 // Old Name New Name
3804 // Simple transfer to new method m -> m
3805 // Add prefix m -> 1_m
3806 // Remove prefix 1_m -> m
3807 // Simultaneous add of prefixes m -> 3_2_1_m
3808 // Simultaneous removal of prefixes 3_2_1_m -> m
3809 // Simultaneous add and remove 1_m -> 2_m
3810 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3811 //
3812 class TransferNativeFunctionRegistration {
3813 private:
3814 InstanceKlass* the_class;
3815 int prefix_count;
3816 char** prefixes;
3817
3818 // Recursively search the binary tree of possibly prefixed method names.
3819 // Iteration could be used if all agents were well behaved. Full tree walk is
3820 // more resilent to agents not cleaning up intermediate methods.
3821 // Branch at each depth in the binary tree is:
3822 // (1) without the prefix.
3823 // (2) with the prefix.
3824 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3825 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3826 Symbol* signature) {
3827 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3828 if (name_symbol != NULL) {
3829 Method* method = the_class->lookup_method(name_symbol, signature);
3830 if (method != NULL) {
3831 // Even if prefixed, intermediate methods must exist.
3832 if (method->is_native()) {
3833 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3834 return method;
3835 }
3836 if (depth < prefix_count) {
3837 // Try applying further prefixes (other than this one).
3838 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3839 if (method != NULL) {
3840 return method; // found
3841 }
3842
3843 // Try adding this prefix to the method name and see if it matches
3844 // another method name.
3845 char* prefix = prefixes[depth];
3846 size_t prefix_len = strlen(prefix);
3847 size_t trial_len = name_len + prefix_len;
3848 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3849 strcpy(trial_name_str, prefix);
3850 strcat(trial_name_str, name_str);
3851 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3852 signature);
3853 if (method != NULL) {
3854 // If found along this branch, it was prefixed, mark as such
3855 method->set_is_prefixed_native();
3856 return method; // found
3857 }
3858 }
3859 }
3860 }
3861 return NULL; // This whole branch bore nothing
3862 }
3863
3864 // Return the method name with old prefixes stripped away.
3865 char* method_name_without_prefixes(Method* method) {
3866 Symbol* name = method->name();
3867 char* name_str = name->as_utf8();
3868
3869 // Old prefixing may be defunct, strip prefixes, if any.
3870 for (int i = prefix_count-1; i >= 0; i--) {
3871 char* prefix = prefixes[i];
3872 size_t prefix_len = strlen(prefix);
3873 if (strncmp(prefix, name_str, prefix_len) == 0) {
3874 name_str += prefix_len;
3875 }
3876 }
3877 return name_str;
3878 }
3879
3880 // Strip any prefixes off the old native method, then try to find a
3881 // (possibly prefixed) new native that matches it.
3882 Method* strip_and_search_for_new_native(Method* method) {
3883 ResourceMark rm;
3884 char* name_str = method_name_without_prefixes(method);
3885 return search_prefix_name_space(0, name_str, strlen(name_str),
3886 method->signature());
3887 }
3888
3889 public:
3890
3891 // Construct a native method transfer processor for this class.
3892 TransferNativeFunctionRegistration(InstanceKlass* _the_class) {
3893 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3894
3895 the_class = _the_class;
3896 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3897 }
3898
3899 // Attempt to transfer any of the old or deleted methods that are native
3900 void transfer_registrations(Method** old_methods, int methods_length) {
3901 for (int j = 0; j < methods_length; j++) {
3902 Method* old_method = old_methods[j];
3903
3904 if (old_method->is_native() && old_method->has_native_function()) {
3905 Method* new_method = strip_and_search_for_new_native(old_method);
3906 if (new_method != NULL) {
3907 // Actually set the native function in the new method.
3908 // Redefine does not send events (except CFLH), certainly not this
3909 // behind the scenes re-registration.
3910 new_method->set_native_function(old_method->native_function(),
3911 !Method::native_bind_event_is_interesting);
3912 }
3913 }
3914 }
3915 }
3916 };
3917
3918 // Don't lose the association between a native method and its JNI function.
3919 void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* the_class) {
3920 TransferNativeFunctionRegistration transfer(the_class);
3921 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3922 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3923 }
3924
3925 // Deoptimize all compiled code that depends on this class.
3926 //
3927 // If the can_redefine_classes capability is obtained in the onload
3928 // phase then the compiler has recorded all dependencies from startup.
3929 // In that case we need only deoptimize and throw away all compiled code
3930 // that depends on the class.
3931 //
3932 // If can_redefine_classes is obtained sometime after the onload
3933 // phase then the dependency information may be incomplete. In that case
3934 // the first call to RedefineClasses causes all compiled code to be
3935 // thrown away. As can_redefine_classes has been obtained then
3936 // all future compilations will record dependencies so second and
3937 // subsequent calls to RedefineClasses need only throw away code
3938 // that depends on the class.
3939 //
3940
3941 // First step is to walk the code cache for each class redefined and mark
3942 // dependent methods. Wait until all classes are processed to deoptimize everything.
3943 void VM_RedefineClasses::mark_dependent_code(InstanceKlass* ik) {
3944 assert_locked_or_safepoint(Compile_lock);
3945
3946 // All dependencies have been recorded from startup or this is a second or
3947 // subsequent use of RedefineClasses
3948 if (JvmtiExport::all_dependencies_are_recorded()) {
3949 CodeCache::mark_for_evol_deoptimization(ik);
3950 }
3951 }
3952
3953 void VM_RedefineClasses::flush_dependent_code() {
3954 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3955
3956 bool deopt_needed;
3957
3958 // This is the first redefinition, mark all the nmethods for deoptimization
3959 if (!JvmtiExport::all_dependencies_are_recorded()) {
3960 log_debug(redefine, class, nmethod)("Marked all nmethods for deopt");
3961 CodeCache::mark_all_nmethods_for_evol_deoptimization();
3962 deopt_needed = true;
3963 } else {
3964 int deopt = CodeCache::mark_dependents_for_evol_deoptimization();
3965 log_debug(redefine, class, nmethod)("Marked %d dependent nmethods for deopt", deopt);
3966 deopt_needed = (deopt != 0);
3967 }
3968
3969 if (deopt_needed) {
3970 CodeCache::flush_evol_dependents();
3971 }
3972
3973 // From now on we know that the dependency information is complete
3974 JvmtiExport::set_all_dependencies_are_recorded(true);
3975 }
3976
3977 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3978 Method* old_method;
3979 Method* new_method;
3980
3981 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3982 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3983 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3984 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3985
3986 _matching_methods_length = 0;
3987 _deleted_methods_length = 0;
3988 _added_methods_length = 0;
3989
3990 int nj = 0;
3991 int oj = 0;
3992 while (true) {
3993 if (oj >= _old_methods->length()) {
3994 if (nj >= _new_methods->length()) {
3995 break; // we've looked at everything, done
3996 }
3997 // New method at the end
3998 new_method = _new_methods->at(nj);
3999 _added_methods[_added_methods_length++] = new_method;
4000 ++nj;
4001 } else if (nj >= _new_methods->length()) {
4002 // Old method, at the end, is deleted
4003 old_method = _old_methods->at(oj);
4004 _deleted_methods[_deleted_methods_length++] = old_method;
4005 ++oj;
4006 } else {
4007 old_method = _old_methods->at(oj);
4008 new_method = _new_methods->at(nj);
4009 if (old_method->name() == new_method->name()) {
4010 if (old_method->signature() == new_method->signature()) {
4011 _matching_old_methods[_matching_methods_length ] = old_method;
4012 _matching_new_methods[_matching_methods_length++] = new_method;
4013 ++nj;
4014 ++oj;
4015 } else {
4016 // added overloaded have already been moved to the end,
4017 // so this is a deleted overloaded method
4018 _deleted_methods[_deleted_methods_length++] = old_method;
4019 ++oj;
4020 }
4021 } else { // names don't match
4022 if (old_method->name()->fast_compare(new_method->name()) > 0) {
4023 // new method
4024 _added_methods[_added_methods_length++] = new_method;
4025 ++nj;
4026 } else {
4027 // deleted method
4028 _deleted_methods[_deleted_methods_length++] = old_method;
4029 ++oj;
4030 }
4031 }
4032 }
4033 }
4034 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
4035 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
4036 }
4037
4038
4039 void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class,
4040 InstanceKlass* scratch_class) {
4041 // Swap annotation fields values
4042 Annotations* old_annotations = the_class->annotations();
4043 the_class->set_annotations(scratch_class->annotations());
4044 scratch_class->set_annotations(old_annotations);
4045 }
4046
4047
4048 // Install the redefinition of a class:
4049 // - house keeping (flushing breakpoints and caches, deoptimizing
4050 // dependent compiled code)
4051 // - replacing parts in the_class with parts from scratch_class
4052 // - adding a weak reference to track the obsolete but interesting
4053 // parts of the_class
4054 // - adjusting constant pool caches and vtables in other classes
4055 // that refer to methods in the_class. These adjustments use the
4056 // ClassLoaderDataGraph::classes_do() facility which only allows
4057 // a helper method to be specified. The interesting parameters
4058 // that we would like to pass to the helper method are saved in
4059 // static global fields in the VM operation.
4060 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
4061 InstanceKlass* scratch_class, TRAPS) {
4062
4063 HandleMark hm(THREAD); // make sure handles from this call are freed
4064
4065 if (log_is_enabled(Info, redefine, class, timer)) {
4066 _timer_rsc_phase1.start();
4067 }
4068
4069 InstanceKlass* the_class = get_ik(the_jclass);
4070
4071 // Set some flags to control and optimize adjusting method entries
4072 _has_redefined_Object |= the_class == SystemDictionary::Object_klass();
4073 _has_null_class_loader |= the_class->class_loader() == NULL;
4074
4075 // Remove all breakpoints in methods of this class
4076 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
4077 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class);
4078
4079 // Mark all compiled code that depends on this class
4080 mark_dependent_code(the_class);
4081
4082 _old_methods = the_class->methods();
4083 _new_methods = scratch_class->methods();
4084 _the_class = the_class;
4085 compute_added_deleted_matching_methods();
4086 update_jmethod_ids(THREAD);
4087
4088 _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods;
4089
4090 // Attach new constant pool to the original klass. The original
4091 // klass still refers to the old constant pool (for now).
4092 scratch_class->constants()->set_pool_holder(the_class);
4093
4094 #if 0
4095 // In theory, with constant pool merging in place we should be able
4096 // to save space by using the new, merged constant pool in place of
4097 // the old constant pool(s). By "pool(s)" I mean the constant pool in
4098 // the klass version we are replacing now and any constant pool(s) in
4099 // previous versions of klass. Nice theory, doesn't work in practice.
4100 // When this code is enabled, even simple programs throw NullPointer
4101 // exceptions. I'm guessing that this is caused by some constant pool
4102 // cache difference between the new, merged constant pool and the
4103 // constant pool that was just being used by the klass. I'm keeping
4104 // this code around to archive the idea, but the code has to remain
4105 // disabled for now.
4106
4107 // Attach each old method to the new constant pool. This can be
4108 // done here since we are past the bytecode verification and
4109 // constant pool optimization phases.
4110 for (int i = _old_methods->length() - 1; i >= 0; i--) {
4111 Method* method = _old_methods->at(i);
4112 method->set_constants(scratch_class->constants());
4113 }
4114
4115 // NOTE: this doesn't work because you can redefine the same class in two
4116 // threads, each getting their own constant pool data appended to the
4117 // original constant pool. In order for the new methods to work when they
4118 // become old methods, they need to keep their updated copy of the constant pool.
4119
4120 {
4121 // walk all previous versions of the klass
4122 InstanceKlass *ik = the_class;
4123 PreviousVersionWalker pvw(ik);
4124 do {
4125 ik = pvw.next_previous_version();
4126 if (ik != NULL) {
4127
4128 // attach previous version of klass to the new constant pool
4129 ik->set_constants(scratch_class->constants());
4130
4131 // Attach each method in the previous version of klass to the
4132 // new constant pool
4133 Array<Method*>* prev_methods = ik->methods();
4134 for (int i = prev_methods->length() - 1; i >= 0; i--) {
4135 Method* method = prev_methods->at(i);
4136 method->set_constants(scratch_class->constants());
4137 }
4138 }
4139 } while (ik != NULL);
4140 }
4141 #endif
4142
4143 // Replace methods and constantpool
4144 the_class->set_methods(_new_methods);
4145 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
4146 // and to be able to undo operation easily.
4147
4148 Array<int>* old_ordering = the_class->method_ordering();
4149 the_class->set_method_ordering(scratch_class->method_ordering());
4150 scratch_class->set_method_ordering(old_ordering);
4151
4152 ConstantPool* old_constants = the_class->constants();
4153 the_class->set_constants(scratch_class->constants());
4154 scratch_class->set_constants(old_constants); // See the previous comment.
4155 #if 0
4156 // We are swapping the guts of "the new class" with the guts of "the
4157 // class". Since the old constant pool has just been attached to "the
4158 // new class", it seems logical to set the pool holder in the old
4159 // constant pool also. However, doing this will change the observable
4160 // class hierarchy for any old methods that are still executing. A
4161 // method can query the identity of its "holder" and this query uses
4162 // the method's constant pool link to find the holder. The change in
4163 // holding class from "the class" to "the new class" can confuse
4164 // things.
4165 //
4166 // Setting the old constant pool's holder will also cause
4167 // verification done during vtable initialization below to fail.
4168 // During vtable initialization, the vtable's class is verified to be
4169 // a subtype of the method's holder. The vtable's class is "the
4170 // class" and the method's holder is gotten from the constant pool
4171 // link in the method itself. For "the class"'s directly implemented
4172 // methods, the method holder is "the class" itself (as gotten from
4173 // the new constant pool). The check works fine in this case. The
4174 // check also works fine for methods inherited from super classes.
4175 //
4176 // Miranda methods are a little more complicated. A miranda method is
4177 // provided by an interface when the class implementing the interface
4178 // does not provide its own method. These interfaces are implemented
4179 // internally as an InstanceKlass. These special instanceKlasses
4180 // share the constant pool of the class that "implements" the
4181 // interface. By sharing the constant pool, the method holder of a
4182 // miranda method is the class that "implements" the interface. In a
4183 // non-redefine situation, the subtype check works fine. However, if
4184 // the old constant pool's pool holder is modified, then the check
4185 // fails because there is no class hierarchy relationship between the
4186 // vtable's class and "the new class".
4187
4188 old_constants->set_pool_holder(scratch_class());
4189 #endif
4190
4191 // track number of methods that are EMCP for add_previous_version() call below
4192 int emcp_method_count = check_methods_and_mark_as_obsolete();
4193 transfer_old_native_function_registrations(the_class);
4194
4195 // The class file bytes from before any retransformable agents mucked
4196 // with them was cached on the scratch class, move to the_class.
4197 // Note: we still want to do this if nothing needed caching since it
4198 // should get cleared in the_class too.
4199 if (the_class->get_cached_class_file() == 0) {
4200 // the_class doesn't have a cache yet so copy it
4201 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
4202 }
4203 else if (scratch_class->get_cached_class_file() !=
4204 the_class->get_cached_class_file()) {
4205 // The same class can be present twice in the scratch classes list or there
4206 // are multiple concurrent RetransformClasses calls on different threads.
4207 // In such cases we have to deallocate scratch_class cached_class_file.
4208 os::free(scratch_class->get_cached_class_file());
4209 }
4210
4211 // NULL out in scratch class to not delete twice. The class to be redefined
4212 // always owns these bytes.
4213 scratch_class->set_cached_class_file(NULL);
4214
4215 // Replace inner_classes
4216 Array<u2>* old_inner_classes = the_class->inner_classes();
4217 the_class->set_inner_classes(scratch_class->inner_classes());
4218 scratch_class->set_inner_classes(old_inner_classes);
4219
4220 // Initialize the vtable and interface table after
4221 // methods have been rewritten
4222 // no exception should happen here since we explicitly
4223 // do not check loader constraints.
4224 // compare_and_normalize_class_versions has already checked:
4225 // - classloaders unchanged, signatures unchanged
4226 // - all instanceKlasses for redefined classes reused & contents updated
4227 the_class->vtable().initialize_vtable(false, THREAD);
4228 the_class->itable().initialize_itable(false, THREAD);
4229 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4230
4231 // Leave arrays of jmethodIDs and itable index cache unchanged
4232
4233 // Copy the "source file name" attribute from new class version
4234 the_class->set_source_file_name_index(
4235 scratch_class->source_file_name_index());
4236
4237 // Copy the "source debug extension" attribute from new class version
4238 the_class->set_source_debug_extension(
4239 scratch_class->source_debug_extension(),
4240 scratch_class->source_debug_extension() == NULL ? 0 :
4241 (int)strlen(scratch_class->source_debug_extension()));
4242
4243 // Use of javac -g could be different in the old and the new
4244 if (scratch_class->access_flags().has_localvariable_table() !=
4245 the_class->access_flags().has_localvariable_table()) {
4246
4247 AccessFlags flags = the_class->access_flags();
4248 if (scratch_class->access_flags().has_localvariable_table()) {
4249 flags.set_has_localvariable_table();
4250 } else {
4251 flags.clear_has_localvariable_table();
4252 }
4253 the_class->set_access_flags(flags);
4254 }
4255
4256 swap_annotations(the_class, scratch_class);
4257
4258 // Replace minor version number of class file
4259 u2 old_minor_version = the_class->minor_version();
4260 the_class->set_minor_version(scratch_class->minor_version());
4261 scratch_class->set_minor_version(old_minor_version);
4262
4263 // Replace major version number of class file
4264 u2 old_major_version = the_class->major_version();
4265 the_class->set_major_version(scratch_class->major_version());
4266 scratch_class->set_major_version(old_major_version);
4267
4268 // Replace CP indexes for class and name+type of enclosing method
4269 u2 old_class_idx = the_class->enclosing_method_class_index();
4270 u2 old_method_idx = the_class->enclosing_method_method_index();
4271 the_class->set_enclosing_method_indices(
4272 scratch_class->enclosing_method_class_index(),
4273 scratch_class->enclosing_method_method_index());
4274 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4275
4276 // Replace fingerprint data
4277 the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check());
4278 the_class->store_fingerprint(scratch_class->get_stored_fingerprint());
4279
4280 the_class->set_has_been_redefined();
4281
4282 if (!the_class->should_be_initialized()) {
4283 // Class was already initialized, so AOT has only seen the original version.
4284 // We need to let AOT look at it again.
4285 AOTLoader::load_for_klass(the_class, THREAD);
4286 }
4287
4288 // keep track of previous versions of this class
4289 the_class->add_previous_version(scratch_class, emcp_method_count);
4290
4291 _timer_rsc_phase1.stop();
4292 if (log_is_enabled(Info, redefine, class, timer)) {
4293 _timer_rsc_phase2.start();
4294 }
4295
4296 if (the_class->oop_map_cache() != NULL) {
4297 // Flush references to any obsolete methods from the oop map cache
4298 // so that obsolete methods are not pinned.
4299 the_class->oop_map_cache()->flush_obsolete_entries();
4300 }
4301
4302 increment_class_counter((InstanceKlass *)the_class, THREAD);
4303
4304 if (EventClassRedefinition::is_enabled()) {
4305 EventClassRedefinition event;
4306 event.set_classModificationCount(java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4307 event.set_redefinedClass(the_class);
4308 event.set_redefinitionId(_id);
4309 event.commit();
4310 }
4311
4312 {
4313 ResourceMark rm(THREAD);
4314 // increment the classRedefinedCount field in the_class and in any
4315 // direct and indirect subclasses of the_class
4316 log_info(redefine, class, load)
4317 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4318 the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10);
4319 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4320 the_class->external_name(),
4321 java_lang_Class::classRedefinedCount(the_class->java_mirror()));
4322
4323 }
4324 _timer_rsc_phase2.stop();
4325
4326 } // end redefine_single_class()
4327
4328
4329 // Increment the classRedefinedCount field in the specific InstanceKlass
4330 // and in all direct and indirect subclasses.
4331 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4332 oop class_mirror = ik->java_mirror();
4333 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4334 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4335 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4336
4337 if (class_oop != _the_class) {
4338 // _the_class count is printed at end of redefine_single_class()
4339 log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count);
4340 }
4341
4342 for (Klass *subk = ik->subklass(); subk != NULL;
4343 subk = subk->next_sibling()) {
4344 if (subk->is_instance_klass()) {
4345 // Only update instanceKlasses
4346 InstanceKlass *subik = InstanceKlass::cast(subk);
4347 // recursively do subclasses of the current subclass
4348 increment_class_counter(subik, THREAD);
4349 }
4350 }
4351 }
4352
4353 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4354 bool no_old_methods = true; // be optimistic
4355
4356 // Both array and instance classes have vtables.
4357 // a vtable should never contain old or obsolete methods
4358 ResourceMark rm(_thread);
4359 if (k->vtable_length() > 0 &&
4360 !k->vtable().check_no_old_or_obsolete_entries()) {
4361 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4362 log_trace(redefine, class, obsolete, metadata)
4363 ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4364 k->signature_name());
4365 k->vtable().dump_vtable();
4366 }
4367 no_old_methods = false;
4368 }
4369
4370 if (k->is_instance_klass()) {
4371 HandleMark hm(_thread);
4372 InstanceKlass *ik = InstanceKlass::cast(k);
4373
4374 // an itable should never contain old or obsolete methods
4375 if (ik->itable_length() > 0 &&
4376 !ik->itable().check_no_old_or_obsolete_entries()) {
4377 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4378 log_trace(redefine, class, obsolete, metadata)
4379 ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4380 ik->signature_name());
4381 ik->itable().dump_itable();
4382 }
4383 no_old_methods = false;
4384 }
4385
4386 // the constant pool cache should never contain non-deleted old or obsolete methods
4387 if (ik->constants() != NULL &&
4388 ik->constants()->cache() != NULL &&
4389 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4390 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4391 log_trace(redefine, class, obsolete, metadata)
4392 ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s",
4393 ik->signature_name());
4394 ik->constants()->cache()->dump_cache();
4395 }
4396 no_old_methods = false;
4397 }
4398 }
4399
4400 // print and fail guarantee if old methods are found.
4401 if (!no_old_methods) {
4402 if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) {
4403 dump_methods();
4404 } else {
4405 log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option "
4406 "to see more info about the following guarantee() failure.");
4407 }
4408 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4409 }
4410 }
4411
4412 u8 VM_RedefineClasses::next_id() {
4413 while (true) {
4414 u8 id = _id_counter;
4415 u8 next_id = id + 1;
4416 u8 result = Atomic::cmpxchg(&_id_counter, id, next_id);
4417 if (result == id) {
4418 return next_id;
4419 }
4420 }
4421 }
4422
4423 void VM_RedefineClasses::dump_methods() {
4424 int j;
4425 log_trace(redefine, class, dump)("_old_methods --");
4426 for (j = 0; j < _old_methods->length(); ++j) {
4427 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4428 Method* m = _old_methods->at(j);
4429 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4430 m->access_flags().print_on(&log_stream);
4431 log_stream.print(" -- ");
4432 m->print_name(&log_stream);
4433 log_stream.cr();
4434 }
4435 log_trace(redefine, class, dump)("_new_methods --");
4436 for (j = 0; j < _new_methods->length(); ++j) {
4437 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4438 Method* m = _new_methods->at(j);
4439 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4440 m->access_flags().print_on(&log_stream);
4441 log_stream.print(" -- ");
4442 m->print_name(&log_stream);
4443 log_stream.cr();
4444 }
4445 log_trace(redefine, class, dump)("_matching_methods --");
4446 for (j = 0; j < _matching_methods_length; ++j) {
4447 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4448 Method* m = _matching_old_methods[j];
4449 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4450 m->access_flags().print_on(&log_stream);
4451 log_stream.print(" -- ");
4452 m->print_name();
4453 log_stream.cr();
4454
4455 m = _matching_new_methods[j];
4456 log_stream.print(" (%5d) ", m->vtable_index());
4457 m->access_flags().print_on(&log_stream);
4458 log_stream.cr();
4459 }
4460 log_trace(redefine, class, dump)("_deleted_methods --");
4461 for (j = 0; j < _deleted_methods_length; ++j) {
4462 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4463 Method* m = _deleted_methods[j];
4464 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4465 m->access_flags().print_on(&log_stream);
4466 log_stream.print(" -- ");
4467 m->print_name(&log_stream);
4468 log_stream.cr();
4469 }
4470 log_trace(redefine, class, dump)("_added_methods --");
4471 for (j = 0; j < _added_methods_length; ++j) {
4472 LogStreamHandle(Trace, redefine, class, dump) log_stream;
4473 Method* m = _added_methods[j];
4474 log_stream.print("%4d (%5d) ", j, m->vtable_index());
4475 m->access_flags().print_on(&log_stream);
4476 log_stream.print(" -- ");
4477 m->print_name(&log_stream);
4478 log_stream.cr();
4479 }
4480 }
4481
4482 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4483 VM_Operation::print_on_error(st);
4484 if (_the_class != NULL) {
4485 ResourceMark rm;
4486 st->print_cr(", redefining class %s", _the_class->external_name());
4487 }
4488 }