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