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