Thu, 23 Jun 2011 17:14:06 -0700
7056328: JSR 292 invocation sometimes fails in adapters for types not on boot class path
Reviewed-by: never
1 /*
2 * Copyright (c) 2003, 2011, 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 */
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "classfile/verifier.hpp"
28 #include "code/codeCache.hpp"
29 #include "interpreter/oopMapCache.hpp"
30 #include "interpreter/rewriter.hpp"
31 #include "memory/gcLocker.hpp"
32 #include "memory/universe.inline.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "prims/jvmtiImpl.hpp"
35 #include "prims/jvmtiRedefineClasses.hpp"
36 #include "prims/methodComparator.hpp"
37 #include "runtime/deoptimization.hpp"
38 #include "runtime/relocator.hpp"
39 #include "utilities/bitMap.inline.hpp"
42 objArrayOop VM_RedefineClasses::_old_methods = NULL;
43 objArrayOop VM_RedefineClasses::_new_methods = NULL;
44 methodOop* VM_RedefineClasses::_matching_old_methods = NULL;
45 methodOop* VM_RedefineClasses::_matching_new_methods = NULL;
46 methodOop* VM_RedefineClasses::_deleted_methods = NULL;
47 methodOop* VM_RedefineClasses::_added_methods = NULL;
48 int VM_RedefineClasses::_matching_methods_length = 0;
49 int VM_RedefineClasses::_deleted_methods_length = 0;
50 int VM_RedefineClasses::_added_methods_length = 0;
51 klassOop VM_RedefineClasses::_the_class_oop = NULL;
54 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
55 const jvmtiClassDefinition *class_defs,
56 JvmtiClassLoadKind class_load_kind) {
57 _class_count = class_count;
58 _class_defs = class_defs;
59 _class_load_kind = class_load_kind;
60 _res = JVMTI_ERROR_NONE;
61 }
63 bool VM_RedefineClasses::doit_prologue() {
64 if (_class_count == 0) {
65 _res = JVMTI_ERROR_NONE;
66 return false;
67 }
68 if (_class_defs == NULL) {
69 _res = JVMTI_ERROR_NULL_POINTER;
70 return false;
71 }
72 for (int i = 0; i < _class_count; i++) {
73 if (_class_defs[i].klass == NULL) {
74 _res = JVMTI_ERROR_INVALID_CLASS;
75 return false;
76 }
77 if (_class_defs[i].class_byte_count == 0) {
78 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
79 return false;
80 }
81 if (_class_defs[i].class_bytes == NULL) {
82 _res = JVMTI_ERROR_NULL_POINTER;
83 return false;
84 }
85 }
87 // Start timer after all the sanity checks; not quite accurate, but
88 // better than adding a bunch of stop() calls.
89 RC_TIMER_START(_timer_vm_op_prologue);
91 // We first load new class versions in the prologue, because somewhere down the
92 // call chain it is required that the current thread is a Java thread.
93 _res = load_new_class_versions(Thread::current());
94 if (_res != JVMTI_ERROR_NONE) {
95 // Free os::malloc allocated memory in load_new_class_version.
96 os::free(_scratch_classes);
97 RC_TIMER_STOP(_timer_vm_op_prologue);
98 return false;
99 }
101 RC_TIMER_STOP(_timer_vm_op_prologue);
102 return true;
103 }
105 void VM_RedefineClasses::doit() {
106 Thread *thread = Thread::current();
108 if (UseSharedSpaces) {
109 // Sharing is enabled so we remap the shared readonly space to
110 // shared readwrite, private just in case we need to redefine
111 // a shared class. We do the remap during the doit() phase of
112 // the safepoint to be safer.
113 if (!CompactingPermGenGen::remap_shared_readonly_as_readwrite()) {
114 RC_TRACE_WITH_THREAD(0x00000001, thread,
115 ("failed to remap shared readonly space to readwrite, private"));
116 _res = JVMTI_ERROR_INTERNAL;
117 return;
118 }
119 }
121 for (int i = 0; i < _class_count; i++) {
122 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
123 }
124 // Disable any dependent concurrent compilations
125 SystemDictionary::notice_modification();
127 // Set flag indicating that some invariants are no longer true.
128 // See jvmtiExport.hpp for detailed explanation.
129 JvmtiExport::set_has_redefined_a_class();
131 #ifdef ASSERT
132 SystemDictionary::classes_do(check_class, thread);
133 #endif
134 }
136 void VM_RedefineClasses::doit_epilogue() {
137 // Free os::malloc allocated memory.
138 // The memory allocated in redefine will be free'ed in next VM operation.
139 os::free(_scratch_classes);
141 if (RC_TRACE_ENABLED(0x00000004)) {
142 // Used to have separate timers for "doit" and "all", but the timer
143 // overhead skewed the measurements.
144 jlong doit_time = _timer_rsc_phase1.milliseconds() +
145 _timer_rsc_phase2.milliseconds();
146 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
148 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
149 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
150 _timer_vm_op_prologue.milliseconds(), doit_time));
151 RC_TRACE(0x00000004,
152 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
153 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
154 }
155 }
157 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
158 // classes for primitives cannot be redefined
159 if (java_lang_Class::is_primitive(klass_mirror)) {
160 return false;
161 }
162 klassOop the_class_oop = java_lang_Class::as_klassOop(klass_mirror);
163 // classes for arrays cannot be redefined
164 if (the_class_oop == NULL || !Klass::cast(the_class_oop)->oop_is_instance()) {
165 return false;
166 }
167 return true;
168 }
170 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
171 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
172 // direct CP entries, there is just the current entry to append. For
173 // indirect and double-indirect CP entries, there are zero or more
174 // referenced CP entries along with the current entry to append.
175 // Indirect and double-indirect CP entries are handled by recursive
176 // calls to append_entry() as needed. The referenced CP entries are
177 // always appended to *merge_cp_p before the referee CP entry. These
178 // referenced CP entries may already exist in *merge_cp_p in which case
179 // there is nothing extra to append and only the current entry is
180 // appended.
181 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
182 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
183 TRAPS) {
185 // append is different depending on entry tag type
186 switch (scratch_cp->tag_at(scratch_i).value()) {
188 // The old verifier is implemented outside the VM. It loads classes,
189 // but does not resolve constant pool entries directly so we never
190 // see Class entries here with the old verifier. Similarly the old
191 // verifier does not like Class entries in the input constant pool.
192 // The split-verifier is implemented in the VM so it can optionally
193 // and directly resolve constant pool entries to load classes. The
194 // split-verifier can accept either Class entries or UnresolvedClass
195 // entries in the input constant pool. We revert the appended copy
196 // back to UnresolvedClass so that either verifier will be happy
197 // with the constant pool entry.
198 case JVM_CONSTANT_Class:
199 {
200 // revert the copy to JVM_CONSTANT_UnresolvedClass
201 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
202 scratch_cp->klass_name_at(scratch_i));
204 if (scratch_i != *merge_cp_length_p) {
205 // The new entry in *merge_cp_p is at a different index than
206 // the new entry in scratch_cp so we need to map the index values.
207 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
208 }
209 (*merge_cp_length_p)++;
210 } break;
212 // these are direct CP entries so they can be directly appended,
213 // but double and long take two constant pool entries
214 case JVM_CONSTANT_Double: // fall through
215 case JVM_CONSTANT_Long:
216 {
217 constantPoolOopDesc::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
218 THREAD);
220 if (scratch_i != *merge_cp_length_p) {
221 // The new entry in *merge_cp_p is at a different index than
222 // the new entry in scratch_cp so we need to map the index values.
223 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
224 }
225 (*merge_cp_length_p) += 2;
226 } break;
228 // these are direct CP entries so they can be directly appended
229 case JVM_CONSTANT_Float: // fall through
230 case JVM_CONSTANT_Integer: // fall through
231 case JVM_CONSTANT_Utf8: // fall through
233 // This was an indirect CP entry, but it has been changed into
234 // an interned string so this entry can be directly appended.
235 case JVM_CONSTANT_String: // fall through
237 // These were indirect CP entries, but they have been changed into
238 // Symbol*s so these entries can be directly appended.
239 case JVM_CONSTANT_UnresolvedClass: // fall through
240 case JVM_CONSTANT_UnresolvedString:
241 {
242 constantPoolOopDesc::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
243 THREAD);
245 if (scratch_i != *merge_cp_length_p) {
246 // The new entry in *merge_cp_p is at a different index than
247 // the new entry in scratch_cp so we need to map the index values.
248 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
249 }
250 (*merge_cp_length_p)++;
251 } break;
253 // this is an indirect CP entry so it needs special handling
254 case JVM_CONSTANT_NameAndType:
255 {
256 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
257 int new_name_ref_i = 0;
258 bool match = (name_ref_i < *merge_cp_length_p) &&
259 scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i,
260 THREAD);
261 if (!match) {
262 // forward reference in *merge_cp_p or not a direct match
264 int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p,
265 THREAD);
266 if (found_i != 0) {
267 guarantee(found_i != name_ref_i,
268 "compare_entry_to() and find_matching_entry() do not agree");
270 // Found a matching entry somewhere else in *merge_cp_p so
271 // just need a mapping entry.
272 new_name_ref_i = found_i;
273 map_index(scratch_cp, name_ref_i, found_i);
274 } else {
275 // no match found so we have to append this entry to *merge_cp_p
276 append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p,
277 THREAD);
278 // The above call to append_entry() can only append one entry
279 // so the post call query of *merge_cp_length_p is only for
280 // the sake of consistency.
281 new_name_ref_i = *merge_cp_length_p - 1;
282 }
283 }
285 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
286 int new_signature_ref_i = 0;
287 match = (signature_ref_i < *merge_cp_length_p) &&
288 scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p,
289 signature_ref_i, THREAD);
290 if (!match) {
291 // forward reference in *merge_cp_p or not a direct match
293 int found_i = scratch_cp->find_matching_entry(signature_ref_i,
294 *merge_cp_p, THREAD);
295 if (found_i != 0) {
296 guarantee(found_i != signature_ref_i,
297 "compare_entry_to() and find_matching_entry() do not agree");
299 // Found a matching entry somewhere else in *merge_cp_p so
300 // just need a mapping entry.
301 new_signature_ref_i = found_i;
302 map_index(scratch_cp, signature_ref_i, found_i);
303 } else {
304 // no match found so we have to append this entry to *merge_cp_p
305 append_entry(scratch_cp, signature_ref_i, merge_cp_p,
306 merge_cp_length_p, THREAD);
307 // The above call to append_entry() can only append one entry
308 // so the post call query of *merge_cp_length_p is only for
309 // the sake of consistency.
310 new_signature_ref_i = *merge_cp_length_p - 1;
311 }
312 }
314 // If the referenced entries already exist in *merge_cp_p, then
315 // both new_name_ref_i and new_signature_ref_i will both be 0.
316 // In that case, all we are appending is the current entry.
317 if (new_name_ref_i == 0) {
318 new_name_ref_i = name_ref_i;
319 } else {
320 RC_TRACE(0x00080000,
321 ("NameAndType entry@%d name_ref_index change: %d to %d",
322 *merge_cp_length_p, name_ref_i, new_name_ref_i));
323 }
324 if (new_signature_ref_i == 0) {
325 new_signature_ref_i = signature_ref_i;
326 } else {
327 RC_TRACE(0x00080000,
328 ("NameAndType entry@%d signature_ref_index change: %d to %d",
329 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
330 }
332 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
333 new_name_ref_i, new_signature_ref_i);
334 if (scratch_i != *merge_cp_length_p) {
335 // The new entry in *merge_cp_p is at a different index than
336 // the new entry in scratch_cp so we need to map the index values.
337 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
338 }
339 (*merge_cp_length_p)++;
340 } break;
342 // this is a double-indirect CP entry so it needs special handling
343 case JVM_CONSTANT_Fieldref: // fall through
344 case JVM_CONSTANT_InterfaceMethodref: // fall through
345 case JVM_CONSTANT_Methodref:
346 {
347 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
348 int new_klass_ref_i = 0;
349 bool match = (klass_ref_i < *merge_cp_length_p) &&
350 scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i,
351 THREAD);
352 if (!match) {
353 // forward reference in *merge_cp_p or not a direct match
355 int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p,
356 THREAD);
357 if (found_i != 0) {
358 guarantee(found_i != klass_ref_i,
359 "compare_entry_to() and find_matching_entry() do not agree");
361 // Found a matching entry somewhere else in *merge_cp_p so
362 // just need a mapping entry.
363 new_klass_ref_i = found_i;
364 map_index(scratch_cp, klass_ref_i, found_i);
365 } else {
366 // no match found so we have to append this entry to *merge_cp_p
367 append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p,
368 THREAD);
369 // The above call to append_entry() can only append one entry
370 // so the post call query of *merge_cp_length_p is only for
371 // the sake of consistency. Without the optimization where we
372 // use JVM_CONSTANT_UnresolvedClass, then up to two entries
373 // could be appended.
374 new_klass_ref_i = *merge_cp_length_p - 1;
375 }
376 }
378 int name_and_type_ref_i =
379 scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
380 int new_name_and_type_ref_i = 0;
381 match = (name_and_type_ref_i < *merge_cp_length_p) &&
382 scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p,
383 name_and_type_ref_i, THREAD);
384 if (!match) {
385 // forward reference in *merge_cp_p or not a direct match
387 int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i,
388 *merge_cp_p, THREAD);
389 if (found_i != 0) {
390 guarantee(found_i != name_and_type_ref_i,
391 "compare_entry_to() and find_matching_entry() do not agree");
393 // Found a matching entry somewhere else in *merge_cp_p so
394 // just need a mapping entry.
395 new_name_and_type_ref_i = found_i;
396 map_index(scratch_cp, name_and_type_ref_i, found_i);
397 } else {
398 // no match found so we have to append this entry to *merge_cp_p
399 append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p,
400 merge_cp_length_p, THREAD);
401 // The above call to append_entry() can append more than
402 // one entry so the post call query of *merge_cp_length_p
403 // is required in order to get the right index for the
404 // JVM_CONSTANT_NameAndType entry.
405 new_name_and_type_ref_i = *merge_cp_length_p - 1;
406 }
407 }
409 // If the referenced entries already exist in *merge_cp_p, then
410 // both new_klass_ref_i and new_name_and_type_ref_i will both be
411 // 0. In that case, all we are appending is the current entry.
412 if (new_klass_ref_i == 0) {
413 new_klass_ref_i = klass_ref_i;
414 }
415 if (new_name_and_type_ref_i == 0) {
416 new_name_and_type_ref_i = name_and_type_ref_i;
417 }
419 const char *entry_name;
420 switch (scratch_cp->tag_at(scratch_i).value()) {
421 case JVM_CONSTANT_Fieldref:
422 entry_name = "Fieldref";
423 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
424 new_name_and_type_ref_i);
425 break;
426 case JVM_CONSTANT_InterfaceMethodref:
427 entry_name = "IFMethodref";
428 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
429 new_klass_ref_i, new_name_and_type_ref_i);
430 break;
431 case JVM_CONSTANT_Methodref:
432 entry_name = "Methodref";
433 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
434 new_name_and_type_ref_i);
435 break;
436 default:
437 guarantee(false, "bad switch");
438 break;
439 }
441 if (klass_ref_i != new_klass_ref_i) {
442 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
443 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
444 }
445 if (name_and_type_ref_i != new_name_and_type_ref_i) {
446 RC_TRACE(0x00080000,
447 ("%s entry@%d name_and_type_index changed: %d to %d",
448 entry_name, *merge_cp_length_p, name_and_type_ref_i,
449 new_name_and_type_ref_i));
450 }
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;
460 // At this stage, Class or UnresolvedClass could be here, but not
461 // ClassIndex
462 case JVM_CONSTANT_ClassIndex: // fall through
464 // Invalid is used as the tag for the second constant pool entry
465 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
466 // not be seen by itself.
467 case JVM_CONSTANT_Invalid: // fall through
469 // At this stage, String or UnresolvedString could be here, but not
470 // StringIndex
471 case JVM_CONSTANT_StringIndex: // fall through
473 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
474 // here
475 case JVM_CONSTANT_UnresolvedClassInError: // fall through
477 default:
478 {
479 // leave a breadcrumb
480 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
481 ShouldNotReachHere();
482 } break;
483 } // end switch tag value
484 } // end append_entry()
487 void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class) {
488 typeArrayOop save;
490 save = scratch_class->get_method_annotations_of(i);
491 scratch_class->set_method_annotations_of(i, scratch_class->get_method_annotations_of(j));
492 scratch_class->set_method_annotations_of(j, save);
494 save = scratch_class->get_method_parameter_annotations_of(i);
495 scratch_class->set_method_parameter_annotations_of(i, scratch_class->get_method_parameter_annotations_of(j));
496 scratch_class->set_method_parameter_annotations_of(j, save);
498 save = scratch_class->get_method_default_annotations_of(i);
499 scratch_class->set_method_default_annotations_of(i, scratch_class->get_method_default_annotations_of(j));
500 scratch_class->set_method_default_annotations_of(j, save);
501 }
504 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
505 instanceKlassHandle the_class,
506 instanceKlassHandle scratch_class) {
507 int i;
509 // Check superclasses, or rather their names, since superclasses themselves can be
510 // requested to replace.
511 // Check for NULL superclass first since this might be java.lang.Object
512 if (the_class->super() != scratch_class->super() &&
513 (the_class->super() == NULL || scratch_class->super() == NULL ||
514 Klass::cast(the_class->super())->name() !=
515 Klass::cast(scratch_class->super())->name())) {
516 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
517 }
519 // Check if the number, names and order of directly implemented interfaces are the same.
520 // I think in principle we should just check if the sets of names of directly implemented
521 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
522 // .java file, also changes in .class file) should not matter. However, comparing sets is
523 // technically a bit more difficult, and, more importantly, I am not sure at present that the
524 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
525 // rely on it somewhere.
526 objArrayOop k_interfaces = the_class->local_interfaces();
527 objArrayOop k_new_interfaces = scratch_class->local_interfaces();
528 int n_intfs = k_interfaces->length();
529 if (n_intfs != k_new_interfaces->length()) {
530 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
531 }
532 for (i = 0; i < n_intfs; i++) {
533 if (Klass::cast((klassOop) k_interfaces->obj_at(i))->name() !=
534 Klass::cast((klassOop) k_new_interfaces->obj_at(i))->name()) {
535 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
536 }
537 }
539 // Check whether class is in the error init state.
540 if (the_class->is_in_error_state()) {
541 // TBD #5057930: special error code is needed in 1.6
542 return JVMTI_ERROR_INVALID_CLASS;
543 }
545 // Check whether class modifiers are the same.
546 jushort old_flags = (jushort) the_class->access_flags().get_flags();
547 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
548 if (old_flags != new_flags) {
549 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
550 }
552 // Check if the number, names, types and order of fields declared in these classes
553 // are the same.
554 typeArrayOop k_old_fields = the_class->fields();
555 typeArrayOop k_new_fields = scratch_class->fields();
556 int n_fields = k_old_fields->length();
557 if (n_fields != k_new_fields->length()) {
558 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
559 }
561 for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
562 // access
563 old_flags = k_old_fields->ushort_at(i + instanceKlass::access_flags_offset);
564 new_flags = k_new_fields->ushort_at(i + instanceKlass::access_flags_offset);
565 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
566 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
567 }
568 // offset
569 if (k_old_fields->short_at(i + instanceKlass::low_offset) !=
570 k_new_fields->short_at(i + instanceKlass::low_offset) ||
571 k_old_fields->short_at(i + instanceKlass::high_offset) !=
572 k_new_fields->short_at(i + instanceKlass::high_offset)) {
573 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
574 }
575 // name and signature
576 jshort name_index = k_old_fields->short_at(i + instanceKlass::name_index_offset);
577 jshort sig_index = k_old_fields->short_at(i +instanceKlass::signature_index_offset);
578 Symbol* name_sym1 = the_class->constants()->symbol_at(name_index);
579 Symbol* sig_sym1 = the_class->constants()->symbol_at(sig_index);
580 name_index = k_new_fields->short_at(i + instanceKlass::name_index_offset);
581 sig_index = k_new_fields->short_at(i + instanceKlass::signature_index_offset);
582 Symbol* name_sym2 = scratch_class->constants()->symbol_at(name_index);
583 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(sig_index);
584 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
585 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
586 }
587 }
589 // Do a parallel walk through the old and new methods. Detect
590 // cases where they match (exist in both), have been added in
591 // the new methods, or have been deleted (exist only in the
592 // old methods). The class file parser places methods in order
593 // by method name, but does not order overloaded methods by
594 // signature. In order to determine what fate befell the methods,
595 // this code places the overloaded new methods that have matching
596 // old methods in the same order as the old methods and places
597 // new overloaded methods at the end of overloaded methods of
598 // that name. The code for this order normalization is adapted
599 // from the algorithm used in instanceKlass::find_method().
600 // Since we are swapping out of order entries as we find them,
601 // we only have to search forward through the overloaded methods.
602 // Methods which are added and have the same name as an existing
603 // method (but different signature) will be put at the end of
604 // the methods with that name, and the name mismatch code will
605 // handle them.
606 objArrayHandle k_old_methods(the_class->methods());
607 objArrayHandle k_new_methods(scratch_class->methods());
608 int n_old_methods = k_old_methods->length();
609 int n_new_methods = k_new_methods->length();
611 int ni = 0;
612 int oi = 0;
613 while (true) {
614 methodOop k_old_method;
615 methodOop k_new_method;
616 enum { matched, added, deleted, undetermined } method_was = undetermined;
618 if (oi >= n_old_methods) {
619 if (ni >= n_new_methods) {
620 break; // we've looked at everything, done
621 }
622 // New method at the end
623 k_new_method = (methodOop) k_new_methods->obj_at(ni);
624 method_was = added;
625 } else if (ni >= n_new_methods) {
626 // Old method, at the end, is deleted
627 k_old_method = (methodOop) k_old_methods->obj_at(oi);
628 method_was = deleted;
629 } else {
630 // There are more methods in both the old and new lists
631 k_old_method = (methodOop) k_old_methods->obj_at(oi);
632 k_new_method = (methodOop) k_new_methods->obj_at(ni);
633 if (k_old_method->name() != k_new_method->name()) {
634 // Methods are sorted by method name, so a mismatch means added
635 // or deleted
636 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
637 method_was = added;
638 } else {
639 method_was = deleted;
640 }
641 } else if (k_old_method->signature() == k_new_method->signature()) {
642 // Both the name and signature match
643 method_was = matched;
644 } else {
645 // The name matches, but the signature doesn't, which means we have to
646 // search forward through the new overloaded methods.
647 int nj; // outside the loop for post-loop check
648 for (nj = ni + 1; nj < n_new_methods; nj++) {
649 methodOop m = (methodOop)k_new_methods->obj_at(nj);
650 if (k_old_method->name() != m->name()) {
651 // reached another method name so no more overloaded methods
652 method_was = deleted;
653 break;
654 }
655 if (k_old_method->signature() == m->signature()) {
656 // found a match so swap the methods
657 k_new_methods->obj_at_put(ni, m);
658 k_new_methods->obj_at_put(nj, k_new_method);
659 k_new_method = m;
660 method_was = matched;
661 break;
662 }
663 }
665 if (nj >= n_new_methods) {
666 // reached the end without a match; so method was deleted
667 method_was = deleted;
668 }
669 }
670 }
672 switch (method_was) {
673 case matched:
674 // methods match, be sure modifiers do too
675 old_flags = (jushort) k_old_method->access_flags().get_flags();
676 new_flags = (jushort) k_new_method->access_flags().get_flags();
677 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
678 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
679 }
680 {
681 u2 new_num = k_new_method->method_idnum();
682 u2 old_num = k_old_method->method_idnum();
683 if (new_num != old_num) {
684 methodOop idnum_owner = scratch_class->method_with_idnum(old_num);
685 if (idnum_owner != NULL) {
686 // There is already a method assigned this idnum -- switch them
687 idnum_owner->set_method_idnum(new_num);
688 }
689 k_new_method->set_method_idnum(old_num);
690 swap_all_method_annotations(old_num, new_num, scratch_class);
691 }
692 }
693 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
694 k_new_method->name_and_sig_as_C_string(), ni,
695 k_old_method->name_and_sig_as_C_string(), oi));
696 // advance to next pair of methods
697 ++oi;
698 ++ni;
699 break;
700 case added:
701 // method added, see if it is OK
702 new_flags = (jushort) k_new_method->access_flags().get_flags();
703 if ((new_flags & JVM_ACC_PRIVATE) == 0
704 // hack: private should be treated as final, but alas
705 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
706 ) {
707 // new methods must be private
708 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
709 }
710 {
711 u2 num = the_class->next_method_idnum();
712 if (num == constMethodOopDesc::UNSET_IDNUM) {
713 // cannot add any more methods
714 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
715 }
716 u2 new_num = k_new_method->method_idnum();
717 methodOop idnum_owner = scratch_class->method_with_idnum(num);
718 if (idnum_owner != NULL) {
719 // There is already a method assigned this idnum -- switch them
720 idnum_owner->set_method_idnum(new_num);
721 }
722 k_new_method->set_method_idnum(num);
723 swap_all_method_annotations(new_num, num, scratch_class);
724 }
725 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
726 k_new_method->name_and_sig_as_C_string(), ni));
727 ++ni; // advance to next new method
728 break;
729 case deleted:
730 // method deleted, see if it is OK
731 old_flags = (jushort) k_old_method->access_flags().get_flags();
732 if ((old_flags & JVM_ACC_PRIVATE) == 0
733 // hack: private should be treated as final, but alas
734 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
735 ) {
736 // deleted methods must be private
737 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
738 }
739 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
740 k_old_method->name_and_sig_as_C_string(), oi));
741 ++oi; // advance to next old method
742 break;
743 default:
744 ShouldNotReachHere();
745 }
746 }
748 return JVMTI_ERROR_NONE;
749 }
752 // Find new constant pool index value for old constant pool index value
753 // by seaching the index map. Returns zero (0) if there is no mapped
754 // value for the old constant pool index.
755 int VM_RedefineClasses::find_new_index(int old_index) {
756 if (_index_map_count == 0) {
757 // map is empty so nothing can be found
758 return 0;
759 }
761 if (old_index < 1 || old_index >= _index_map_p->length()) {
762 // The old_index is out of range so it is not mapped. This should
763 // not happen in regular constant pool merging use, but it can
764 // happen if a corrupt annotation is processed.
765 return 0;
766 }
768 int value = _index_map_p->at(old_index);
769 if (value == -1) {
770 // the old_index is not mapped
771 return 0;
772 }
774 return value;
775 } // end find_new_index()
778 // Returns true if the current mismatch is due to a resolved/unresolved
779 // class pair. Otherwise, returns false.
780 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
781 int index1, constantPoolHandle cp2, int index2) {
783 jbyte t1 = cp1->tag_at(index1).value();
784 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
785 return false; // wrong entry type; not our special case
786 }
788 jbyte t2 = cp2->tag_at(index2).value();
789 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
790 return false; // wrong entry type; not our special case
791 }
793 if (t1 == t2) {
794 return false; // not a mismatch; not our special case
795 }
797 char *s1 = cp1->klass_name_at(index1)->as_C_string();
798 char *s2 = cp2->klass_name_at(index2)->as_C_string();
799 if (strcmp(s1, s2) != 0) {
800 return false; // strings don't match; not our special case
801 }
803 return true; // made it through the gauntlet; this is our special case
804 } // end is_unresolved_class_mismatch()
807 // Returns true if the current mismatch is due to a resolved/unresolved
808 // string pair. Otherwise, returns false.
809 bool VM_RedefineClasses::is_unresolved_string_mismatch(constantPoolHandle cp1,
810 int index1, constantPoolHandle cp2, int index2) {
812 jbyte t1 = cp1->tag_at(index1).value();
813 if (t1 != JVM_CONSTANT_String && t1 != JVM_CONSTANT_UnresolvedString) {
814 return false; // wrong entry type; not our special case
815 }
817 jbyte t2 = cp2->tag_at(index2).value();
818 if (t2 != JVM_CONSTANT_String && t2 != JVM_CONSTANT_UnresolvedString) {
819 return false; // wrong entry type; not our special case
820 }
822 if (t1 == t2) {
823 return false; // not a mismatch; not our special case
824 }
826 char *s1 = cp1->string_at_noresolve(index1);
827 char *s2 = cp2->string_at_noresolve(index2);
828 if (strcmp(s1, s2) != 0) {
829 return false; // strings don't match; not our special case
830 }
832 return true; // made it through the gauntlet; this is our special case
833 } // end is_unresolved_string_mismatch()
836 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
837 // For consistency allocate memory using os::malloc wrapper.
838 _scratch_classes = (instanceKlassHandle *)
839 os::malloc(sizeof(instanceKlassHandle) * _class_count);
840 if (_scratch_classes == NULL) {
841 return JVMTI_ERROR_OUT_OF_MEMORY;
842 }
844 ResourceMark rm(THREAD);
846 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
847 // state can only be NULL if the current thread is exiting which
848 // should not happen since we're trying to do a RedefineClasses
849 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
850 for (int i = 0; i < _class_count; i++) {
851 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
852 // classes for primitives cannot be redefined
853 if (!is_modifiable_class(mirror)) {
854 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
855 }
856 klassOop the_class_oop = java_lang_Class::as_klassOop(mirror);
857 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
858 Symbol* the_class_sym = the_class->name();
860 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
861 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
862 ("loading name=%s (avail_mem=" UINT64_FORMAT "K)",
863 the_class->external_name(), os::available_memory() >> 10));
865 ClassFileStream st((u1*) _class_defs[i].class_bytes,
866 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
868 // Parse the stream.
869 Handle the_class_loader(THREAD, the_class->class_loader());
870 Handle protection_domain(THREAD, the_class->protection_domain());
871 // Set redefined class handle in JvmtiThreadState class.
872 // This redefined class is sent to agent event handler for class file
873 // load hook event.
874 state->set_class_being_redefined(&the_class, _class_load_kind);
876 klassOop k = SystemDictionary::parse_stream(the_class_sym,
877 the_class_loader,
878 protection_domain,
879 &st,
880 THREAD);
881 // Clear class_being_redefined just to be sure.
882 state->clear_class_being_redefined();
884 // TODO: if this is retransform, and nothing changed we can skip it
886 instanceKlassHandle scratch_class (THREAD, k);
888 if (HAS_PENDING_EXCEPTION) {
889 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
890 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
891 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
892 ex_name->as_C_string()));
893 CLEAR_PENDING_EXCEPTION;
895 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
896 return JVMTI_ERROR_UNSUPPORTED_VERSION;
897 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
898 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
899 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
900 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
901 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
902 // The message will be "XXX (wrong name: YYY)"
903 return JVMTI_ERROR_NAMES_DONT_MATCH;
904 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
905 return JVMTI_ERROR_OUT_OF_MEMORY;
906 } else { // Just in case more exceptions can be thrown..
907 return JVMTI_ERROR_FAILS_VERIFICATION;
908 }
909 }
911 // Ensure class is linked before redefine
912 if (!the_class->is_linked()) {
913 the_class->link_class(THREAD);
914 if (HAS_PENDING_EXCEPTION) {
915 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
916 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
917 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
918 ex_name->as_C_string()));
919 CLEAR_PENDING_EXCEPTION;
920 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
921 return JVMTI_ERROR_OUT_OF_MEMORY;
922 } else {
923 return JVMTI_ERROR_INTERNAL;
924 }
925 }
926 }
928 // Do the validity checks in compare_and_normalize_class_versions()
929 // before verifying the byte codes. By doing these checks first, we
930 // limit the number of functions that require redirection from
931 // the_class to scratch_class. In particular, we don't have to
932 // modify JNI GetSuperclass() and thus won't change its performance.
933 jvmtiError res = compare_and_normalize_class_versions(the_class,
934 scratch_class);
935 if (res != JVMTI_ERROR_NONE) {
936 return res;
937 }
939 // verify what the caller passed us
940 {
941 // The bug 6214132 caused the verification to fail.
942 // Information about the_class and scratch_class is temporarily
943 // recorded into jvmtiThreadState. This data is used to redirect
944 // the_class to scratch_class in the JVM_* functions called by the
945 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
946 // description.
947 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
948 Verifier::verify(
949 scratch_class, Verifier::ThrowException, true, THREAD);
950 }
952 if (HAS_PENDING_EXCEPTION) {
953 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
954 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
955 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
956 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
957 CLEAR_PENDING_EXCEPTION;
958 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
959 return JVMTI_ERROR_OUT_OF_MEMORY;
960 } else {
961 // tell the caller the bytecodes are bad
962 return JVMTI_ERROR_FAILS_VERIFICATION;
963 }
964 }
966 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
967 if (res != JVMTI_ERROR_NONE) {
968 return res;
969 }
971 if (VerifyMergedCPBytecodes) {
972 // verify what we have done during constant pool merging
973 {
974 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
975 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
976 }
978 if (HAS_PENDING_EXCEPTION) {
979 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
980 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
981 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
982 ("verify_byte_codes post merge-CP exception: '%s'",
983 ex_name->as_C_string()));
984 CLEAR_PENDING_EXCEPTION;
985 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
986 return JVMTI_ERROR_OUT_OF_MEMORY;
987 } else {
988 // tell the caller that constant pool merging screwed up
989 return JVMTI_ERROR_INTERNAL;
990 }
991 }
992 }
994 Rewriter::rewrite(scratch_class, THREAD);
995 if (!HAS_PENDING_EXCEPTION) {
996 Rewriter::relocate_and_link(scratch_class, THREAD);
997 }
998 if (HAS_PENDING_EXCEPTION) {
999 Symbol* ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
1000 CLEAR_PENDING_EXCEPTION;
1001 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1002 return JVMTI_ERROR_OUT_OF_MEMORY;
1003 } else {
1004 return JVMTI_ERROR_INTERNAL;
1005 }
1006 }
1008 _scratch_classes[i] = scratch_class;
1010 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1011 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1012 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1013 the_class->external_name(), os::available_memory() >> 10));
1014 }
1016 return JVMTI_ERROR_NONE;
1017 }
1020 // Map old_index to new_index as needed. scratch_cp is only needed
1021 // for RC_TRACE() calls.
1022 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1023 int old_index, int new_index) {
1024 if (find_new_index(old_index) != 0) {
1025 // old_index is already mapped
1026 return;
1027 }
1029 if (old_index == new_index) {
1030 // no mapping is needed
1031 return;
1032 }
1034 _index_map_p->at_put(old_index, new_index);
1035 _index_map_count++;
1037 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1038 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1039 } // end map_index()
1042 // Merge old_cp and scratch_cp and return the results of the merge via
1043 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1044 // merge_cp_length_p. The entries in old_cp occupy the same locations
1045 // in *merge_cp_p. Also creates a map of indices from entries in
1046 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1047 // entries are only created for entries in scratch_cp that occupy a
1048 // different location in *merged_cp_p.
1049 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1050 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1051 int *merge_cp_length_p, TRAPS) {
1053 if (merge_cp_p == NULL) {
1054 assert(false, "caller must provide scatch constantPool");
1055 return false; // robustness
1056 }
1057 if (merge_cp_length_p == NULL) {
1058 assert(false, "caller must provide scatch CP length");
1059 return false; // robustness
1060 }
1061 // Worst case we need old_cp->length() + scratch_cp()->length(),
1062 // but the caller might be smart so make sure we have at least
1063 // the minimum.
1064 if ((*merge_cp_p)->length() < old_cp->length()) {
1065 assert(false, "merge area too small");
1066 return false; // robustness
1067 }
1069 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1070 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1071 scratch_cp->length()));
1073 {
1074 // Pass 0:
1075 // The old_cp is copied to *merge_cp_p; this means that any code
1076 // using old_cp does not have to change. This work looks like a
1077 // perfect fit for constantPoolOop::copy_cp_to(), but we need to
1078 // handle one special case:
1079 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1080 // This will make verification happy.
1082 int old_i; // index into old_cp
1084 // index zero (0) is not used in constantPools
1085 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1086 // leave debugging crumb
1087 jbyte old_tag = old_cp->tag_at(old_i).value();
1088 switch (old_tag) {
1089 case JVM_CONSTANT_Class:
1090 case JVM_CONSTANT_UnresolvedClass:
1091 // revert the copy to JVM_CONSTANT_UnresolvedClass
1092 // May be resolving while calling this so do the same for
1093 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1094 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1095 old_cp->klass_name_at(old_i));
1096 break;
1098 case JVM_CONSTANT_Double:
1099 case JVM_CONSTANT_Long:
1100 // just copy the entry to *merge_cp_p, but double and long take
1101 // two constant pool entries
1102 constantPoolOopDesc::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1103 old_i++;
1104 break;
1106 default:
1107 // just copy the entry to *merge_cp_p
1108 constantPoolOopDesc::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1109 break;
1110 }
1111 } // end for each old_cp entry
1113 // We don't need to sanity check that *merge_cp_length_p is within
1114 // *merge_cp_p bounds since we have the minimum on-entry check above.
1115 (*merge_cp_length_p) = old_i;
1116 }
1118 // merge_cp_len should be the same as old_cp->length() at this point
1119 // so this trace message is really a "warm-and-breathing" message.
1120 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1121 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1123 int scratch_i; // index into scratch_cp
1124 {
1125 // Pass 1a:
1126 // Compare scratch_cp entries to the old_cp entries that we have
1127 // already copied to *merge_cp_p. In this pass, we are eliminating
1128 // exact duplicates (matching entry at same index) so we only
1129 // compare entries in the common indice range.
1130 int increment = 1;
1131 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1132 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1133 switch (scratch_cp->tag_at(scratch_i).value()) {
1134 case JVM_CONSTANT_Double:
1135 case JVM_CONSTANT_Long:
1136 // double and long take two constant pool entries
1137 increment = 2;
1138 break;
1140 default:
1141 increment = 1;
1142 break;
1143 }
1145 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1146 scratch_i, CHECK_0);
1147 if (match) {
1148 // found a match at the same index so nothing more to do
1149 continue;
1150 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1151 *merge_cp_p, scratch_i)) {
1152 // The mismatch in compare_entry_to() above is because of a
1153 // resolved versus unresolved class entry at the same index
1154 // with the same string value. Since Pass 0 reverted any
1155 // class entries to unresolved class entries in *merge_cp_p,
1156 // we go with the unresolved class entry.
1157 continue;
1158 } else if (is_unresolved_string_mismatch(scratch_cp, scratch_i,
1159 *merge_cp_p, scratch_i)) {
1160 // The mismatch in compare_entry_to() above is because of a
1161 // resolved versus unresolved string entry at the same index
1162 // with the same string value. We can live with whichever
1163 // happens to be at scratch_i in *merge_cp_p.
1164 continue;
1165 }
1167 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1168 CHECK_0);
1169 if (found_i != 0) {
1170 guarantee(found_i != scratch_i,
1171 "compare_entry_to() and find_matching_entry() do not agree");
1173 // Found a matching entry somewhere else in *merge_cp_p so
1174 // just need a mapping entry.
1175 map_index(scratch_cp, scratch_i, found_i);
1176 continue;
1177 }
1179 // The find_matching_entry() call above could fail to find a match
1180 // due to a resolved versus unresolved class or string entry situation
1181 // like we solved above with the is_unresolved_*_mismatch() calls.
1182 // However, we would have to call is_unresolved_*_mismatch() over
1183 // all of *merge_cp_p (potentially) and that doesn't seem to be
1184 // worth the time.
1186 // No match found so we have to append this entry and any unique
1187 // referenced entries to *merge_cp_p.
1188 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1189 CHECK_0);
1190 }
1191 }
1193 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1194 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1195 *merge_cp_length_p, scratch_i, _index_map_count));
1197 if (scratch_i < scratch_cp->length()) {
1198 // Pass 1b:
1199 // old_cp is smaller than scratch_cp so there are entries in
1200 // scratch_cp that we have not yet processed. We take care of
1201 // those now.
1202 int increment = 1;
1203 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1204 switch (scratch_cp->tag_at(scratch_i).value()) {
1205 case JVM_CONSTANT_Double:
1206 case JVM_CONSTANT_Long:
1207 // double and long take two constant pool entries
1208 increment = 2;
1209 break;
1211 default:
1212 increment = 1;
1213 break;
1214 }
1216 int found_i =
1217 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1218 if (found_i != 0) {
1219 // Found a matching entry somewhere else in *merge_cp_p so
1220 // just need a mapping entry.
1221 map_index(scratch_cp, scratch_i, found_i);
1222 continue;
1223 }
1225 // No match found so we have to append this entry and any unique
1226 // referenced entries to *merge_cp_p.
1227 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1228 CHECK_0);
1229 }
1231 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1232 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1233 *merge_cp_length_p, scratch_i, _index_map_count));
1234 }
1236 return true;
1237 } // end merge_constant_pools()
1240 // Merge constant pools between the_class and scratch_class and
1241 // potentially rewrite bytecodes in scratch_class to use the merged
1242 // constant pool.
1243 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1244 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1245 TRAPS) {
1246 // worst case merged constant pool length is old and new combined
1247 int merge_cp_length = the_class->constants()->length()
1248 + scratch_class->constants()->length();
1250 constantPoolHandle old_cp(THREAD, the_class->constants());
1251 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1253 // Constant pools are not easily reused so we allocate a new one
1254 // each time.
1255 // merge_cp is created unsafe for concurrent GC processing. It
1256 // should be marked safe before discarding it. Even though
1257 // garbage, if it crosses a card boundary, it may be scanned
1258 // in order to find the start of the first complete object on the card.
1259 constantPoolHandle merge_cp(THREAD,
1260 oopFactory::new_constantPool(merge_cp_length,
1261 oopDesc::IsUnsafeConc,
1262 THREAD));
1263 int orig_length = old_cp->orig_length();
1264 if (orig_length == 0) {
1265 // This old_cp is an actual original constant pool. We save
1266 // the original length in the merged constant pool so that
1267 // merge_constant_pools() can be more efficient. If a constant
1268 // pool has a non-zero orig_length() value, then that constant
1269 // pool was created by a merge operation in RedefineClasses.
1270 merge_cp->set_orig_length(old_cp->length());
1271 } else {
1272 // This old_cp is a merged constant pool from a previous
1273 // RedefineClasses() calls so just copy the orig_length()
1274 // value.
1275 merge_cp->set_orig_length(old_cp->orig_length());
1276 }
1278 ResourceMark rm(THREAD);
1279 _index_map_count = 0;
1280 _index_map_p = new intArray(scratch_cp->length(), -1);
1282 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1283 &merge_cp_length, THREAD);
1284 if (!result) {
1285 // The merge can fail due to memory allocation failure or due
1286 // to robustness checks.
1287 return JVMTI_ERROR_INTERNAL;
1288 }
1290 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1291 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1293 if (_index_map_count == 0) {
1294 // there is nothing to map between the new and merged constant pools
1296 if (old_cp->length() == scratch_cp->length()) {
1297 // The old and new constant pools are the same length and the
1298 // index map is empty. This means that the three constant pools
1299 // are equivalent (but not the same). Unfortunately, the new
1300 // constant pool has not gone through link resolution nor have
1301 // the new class bytecodes gone through constant pool cache
1302 // rewriting so we can't use the old constant pool with the new
1303 // class.
1305 merge_cp()->set_is_conc_safe(true);
1306 merge_cp = constantPoolHandle(); // toss the merged constant pool
1307 } else if (old_cp->length() < scratch_cp->length()) {
1308 // The old constant pool has fewer entries than the new constant
1309 // pool and the index map is empty. This means the new constant
1310 // pool is a superset of the old constant pool. However, the old
1311 // class bytecodes have already gone through constant pool cache
1312 // rewriting so we can't use the new constant pool with the old
1313 // class.
1315 merge_cp()->set_is_conc_safe(true);
1316 merge_cp = constantPoolHandle(); // toss the merged constant pool
1317 } else {
1318 // The old constant pool has more entries than the new constant
1319 // pool and the index map is empty. This means that both the old
1320 // and merged constant pools are supersets of the new constant
1321 // pool.
1323 // Replace the new constant pool with a shrunken copy of the
1324 // merged constant pool; the previous new constant pool will
1325 // get GCed.
1326 set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
1327 THREAD);
1328 // drop local ref to the merged constant pool
1329 merge_cp()->set_is_conc_safe(true);
1330 merge_cp = constantPoolHandle();
1331 }
1332 } else {
1333 if (RC_TRACE_ENABLED(0x00040000)) {
1334 // don't want to loop unless we are tracing
1335 int count = 0;
1336 for (int i = 1; i < _index_map_p->length(); i++) {
1337 int value = _index_map_p->at(i);
1339 if (value != -1) {
1340 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1341 ("index_map[%d]: old=%d new=%d", count, i, value));
1342 count++;
1343 }
1344 }
1345 }
1347 // We have entries mapped between the new and merged constant pools
1348 // so we have to rewrite some constant pool references.
1349 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1350 return JVMTI_ERROR_INTERNAL;
1351 }
1353 // Replace the new constant pool with a shrunken copy of the
1354 // merged constant pool so now the rewritten bytecodes have
1355 // valid references; the previous new constant pool will get
1356 // GCed.
1357 set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
1358 THREAD);
1359 merge_cp()->set_is_conc_safe(true);
1360 }
1361 assert(old_cp()->is_conc_safe(), "Just checking");
1362 assert(scratch_cp()->is_conc_safe(), "Just checking");
1364 return JVMTI_ERROR_NONE;
1365 } // end merge_cp_and_rewrite()
1368 // Rewrite constant pool references in klass scratch_class.
1369 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1370 TRAPS) {
1372 // rewrite constant pool references in the methods:
1373 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1374 // propagate failure back to caller
1375 return false;
1376 }
1378 // rewrite constant pool references in the class_annotations:
1379 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1380 // propagate failure back to caller
1381 return false;
1382 }
1384 // rewrite constant pool references in the fields_annotations:
1385 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1386 // propagate failure back to caller
1387 return false;
1388 }
1390 // rewrite constant pool references in the methods_annotations:
1391 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1392 // propagate failure back to caller
1393 return false;
1394 }
1396 // rewrite constant pool references in the methods_parameter_annotations:
1397 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1398 THREAD)) {
1399 // propagate failure back to caller
1400 return false;
1401 }
1403 // rewrite constant pool references in the methods_default_annotations:
1404 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1405 THREAD)) {
1406 // propagate failure back to caller
1407 return false;
1408 }
1410 return true;
1411 } // end rewrite_cp_refs()
1414 // Rewrite constant pool references in the methods.
1415 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1416 instanceKlassHandle scratch_class, TRAPS) {
1418 objArrayHandle methods(THREAD, scratch_class->methods());
1420 if (methods.is_null() || methods->length() == 0) {
1421 // no methods so nothing to do
1422 return true;
1423 }
1425 // rewrite constant pool references in the methods:
1426 for (int i = methods->length() - 1; i >= 0; i--) {
1427 methodHandle method(THREAD, (methodOop)methods->obj_at(i));
1428 methodHandle new_method;
1429 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1430 if (!new_method.is_null()) {
1431 // the method has been replaced so save the new method version
1432 methods->obj_at_put(i, new_method());
1433 }
1434 }
1436 return true;
1437 }
1440 // Rewrite constant pool references in the specific method. This code
1441 // was adapted from Rewriter::rewrite_method().
1442 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1443 methodHandle *new_method_p, TRAPS) {
1445 *new_method_p = methodHandle(); // default is no new method
1447 // We cache a pointer to the bytecodes here in code_base. If GC
1448 // moves the methodOop, then the bytecodes will also move which
1449 // will likely cause a crash. We create a No_Safepoint_Verifier
1450 // object to detect whether we pass a possible safepoint in this
1451 // code block.
1452 No_Safepoint_Verifier nsv;
1454 // Bytecodes and their length
1455 address code_base = method->code_base();
1456 int code_length = method->code_size();
1458 int bc_length;
1459 for (int bci = 0; bci < code_length; bci += bc_length) {
1460 address bcp = code_base + bci;
1461 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1463 bc_length = Bytecodes::length_for(c);
1464 if (bc_length == 0) {
1465 // More complicated bytecodes report a length of zero so
1466 // we have to try again a slightly different way.
1467 bc_length = Bytecodes::length_at(method(), bcp);
1468 }
1470 assert(bc_length != 0, "impossible bytecode length");
1472 switch (c) {
1473 case Bytecodes::_ldc:
1474 {
1475 int cp_index = *(bcp + 1);
1476 int new_index = find_new_index(cp_index);
1478 if (StressLdcRewrite && new_index == 0) {
1479 // If we are stressing ldc -> ldc_w rewriting, then we
1480 // always need a new_index value.
1481 new_index = cp_index;
1482 }
1483 if (new_index != 0) {
1484 // the original index is mapped so we have more work to do
1485 if (!StressLdcRewrite && new_index <= max_jubyte) {
1486 // The new value can still use ldc instead of ldc_w
1487 // unless we are trying to stress ldc -> ldc_w rewriting
1488 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1489 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1490 bcp, cp_index, new_index));
1491 *(bcp + 1) = new_index;
1492 } else {
1493 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1494 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1495 Bytecodes::name(c), bcp, cp_index, new_index));
1496 // the new value needs ldc_w instead of ldc
1497 u_char inst_buffer[4]; // max instruction size is 4 bytes
1498 bcp = (address)inst_buffer;
1499 // construct new instruction sequence
1500 *bcp = Bytecodes::_ldc_w;
1501 bcp++;
1502 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1503 // See comment below for difference between put_Java_u2()
1504 // and put_native_u2().
1505 Bytes::put_Java_u2(bcp, new_index);
1507 Relocator rc(method, NULL /* no RelocatorListener needed */);
1508 methodHandle m;
1509 {
1510 Pause_No_Safepoint_Verifier pnsv(&nsv);
1512 // ldc is 2 bytes and ldc_w is 3 bytes
1513 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1514 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1515 guarantee(false, "insert_space_at() failed");
1516 }
1517 }
1519 // return the new method so that the caller can update
1520 // the containing class
1521 *new_method_p = method = m;
1522 // switch our bytecode processing loop from the old method
1523 // to the new method
1524 code_base = method->code_base();
1525 code_length = method->code_size();
1526 bcp = code_base + bci;
1527 c = (Bytecodes::Code)(*bcp);
1528 bc_length = Bytecodes::length_for(c);
1529 assert(bc_length != 0, "sanity check");
1530 } // end we need ldc_w instead of ldc
1531 } // end if there is a mapped index
1532 } break;
1534 // these bytecodes have a two-byte constant pool index
1535 case Bytecodes::_anewarray : // fall through
1536 case Bytecodes::_checkcast : // fall through
1537 case Bytecodes::_getfield : // fall through
1538 case Bytecodes::_getstatic : // fall through
1539 case Bytecodes::_instanceof : // fall through
1540 case Bytecodes::_invokeinterface: // fall through
1541 case Bytecodes::_invokespecial : // fall through
1542 case Bytecodes::_invokestatic : // fall through
1543 case Bytecodes::_invokevirtual : // fall through
1544 case Bytecodes::_ldc_w : // fall through
1545 case Bytecodes::_ldc2_w : // fall through
1546 case Bytecodes::_multianewarray : // fall through
1547 case Bytecodes::_new : // fall through
1548 case Bytecodes::_putfield : // fall through
1549 case Bytecodes::_putstatic :
1550 {
1551 address p = bcp + 1;
1552 int cp_index = Bytes::get_Java_u2(p);
1553 int new_index = find_new_index(cp_index);
1554 if (new_index != 0) {
1555 // the original index is mapped so update w/ new value
1556 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1557 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1558 bcp, cp_index, new_index));
1559 // Rewriter::rewrite_method() uses put_native_u2() in this
1560 // situation because it is reusing the constant pool index
1561 // location for a native index into the constantPoolCache.
1562 // Since we are updating the constant pool index prior to
1563 // verification and constantPoolCache initialization, we
1564 // need to keep the new index in Java byte order.
1565 Bytes::put_Java_u2(p, new_index);
1566 }
1567 } break;
1568 }
1569 } // end for each bytecode
1570 } // end rewrite_cp_refs_in_method()
1573 // Rewrite constant pool references in the class_annotations field.
1574 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1575 instanceKlassHandle scratch_class, TRAPS) {
1577 typeArrayHandle class_annotations(THREAD,
1578 scratch_class->class_annotations());
1579 if (class_annotations.is_null() || class_annotations->length() == 0) {
1580 // no class_annotations so nothing to do
1581 return true;
1582 }
1584 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1585 ("class_annotations length=%d", class_annotations->length()));
1587 int byte_i = 0; // byte index into class_annotations
1588 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1589 THREAD);
1590 }
1593 // Rewrite constant pool references in an annotations typeArray. This
1594 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1595 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1596 //
1597 // annotations_typeArray {
1598 // u2 num_annotations;
1599 // annotation annotations[num_annotations];
1600 // }
1601 //
1602 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1603 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1605 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1606 // not enough room for num_annotations field
1607 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1608 ("length() is too small for num_annotations field"));
1609 return false;
1610 }
1612 u2 num_annotations = Bytes::get_Java_u2((address)
1613 annotations_typeArray->byte_at_addr(byte_i_ref));
1614 byte_i_ref += 2;
1616 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1617 ("num_annotations=%d", num_annotations));
1619 int calc_num_annotations = 0;
1620 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1621 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1622 byte_i_ref, THREAD)) {
1623 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1624 ("bad annotation_struct at %d", calc_num_annotations));
1625 // propagate failure back to caller
1626 return false;
1627 }
1628 }
1629 assert(num_annotations == calc_num_annotations, "sanity check");
1631 return true;
1632 } // end rewrite_cp_refs_in_annotations_typeArray()
1635 // Rewrite constant pool references in the annotation struct portion of
1636 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1637 // the 2nd-edition of the VM spec:
1638 //
1639 // struct annotation {
1640 // u2 type_index;
1641 // u2 num_element_value_pairs;
1642 // {
1643 // u2 element_name_index;
1644 // element_value value;
1645 // } element_value_pairs[num_element_value_pairs];
1646 // }
1647 //
1648 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1649 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1650 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1651 // not enough room for smallest annotation_struct
1652 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1653 ("length() is too small for annotation_struct"));
1654 return false;
1655 }
1657 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1658 byte_i_ref, "mapped old type_index=%d", THREAD);
1660 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1661 annotations_typeArray->byte_at_addr(
1662 byte_i_ref));
1663 byte_i_ref += 2;
1665 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1666 ("type_index=%d num_element_value_pairs=%d", type_index,
1667 num_element_value_pairs));
1669 int calc_num_element_value_pairs = 0;
1670 for (; calc_num_element_value_pairs < num_element_value_pairs;
1671 calc_num_element_value_pairs++) {
1672 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1673 // not enough room for another element_name_index, let alone
1674 // the rest of another component
1675 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1676 ("length() is too small for element_name_index"));
1677 return false;
1678 }
1680 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1681 annotations_typeArray, byte_i_ref,
1682 "mapped old element_name_index=%d", THREAD);
1684 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1685 ("element_name_index=%d", element_name_index));
1687 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1688 byte_i_ref, THREAD)) {
1689 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1690 ("bad element_value at %d", calc_num_element_value_pairs));
1691 // propagate failure back to caller
1692 return false;
1693 }
1694 } // end for each component
1695 assert(num_element_value_pairs == calc_num_element_value_pairs,
1696 "sanity check");
1698 return true;
1699 } // end rewrite_cp_refs_in_annotation_struct()
1702 // Rewrite a constant pool reference at the current position in
1703 // annotations_typeArray if needed. Returns the original constant
1704 // pool reference if a rewrite was not needed or the new constant
1705 // pool reference if a rewrite was needed.
1706 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1707 typeArrayHandle annotations_typeArray, int &byte_i_ref,
1708 const char * trace_mesg, TRAPS) {
1710 address cp_index_addr = (address)
1711 annotations_typeArray->byte_at_addr(byte_i_ref);
1712 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1713 u2 new_cp_index = find_new_index(old_cp_index);
1714 if (new_cp_index != 0) {
1715 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1716 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1717 old_cp_index = new_cp_index;
1718 }
1719 byte_i_ref += 2;
1720 return old_cp_index;
1721 }
1724 // Rewrite constant pool references in the element_value portion of an
1725 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1726 // the 2nd-edition of the VM spec:
1727 //
1728 // struct element_value {
1729 // u1 tag;
1730 // union {
1731 // u2 const_value_index;
1732 // {
1733 // u2 type_name_index;
1734 // u2 const_name_index;
1735 // } enum_const_value;
1736 // u2 class_info_index;
1737 // annotation annotation_value;
1738 // struct {
1739 // u2 num_values;
1740 // element_value values[num_values];
1741 // } array_value;
1742 // } value;
1743 // }
1744 //
1745 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1746 typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
1748 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1749 // not enough room for a tag let alone the rest of an element_value
1750 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1751 ("length() is too small for a tag"));
1752 return false;
1753 }
1755 u1 tag = annotations_typeArray->byte_at(byte_i_ref);
1756 byte_i_ref++;
1757 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1759 switch (tag) {
1760 // These BaseType tag values are from Table 4.2 in VM spec:
1761 case 'B': // byte
1762 case 'C': // char
1763 case 'D': // double
1764 case 'F': // float
1765 case 'I': // int
1766 case 'J': // long
1767 case 'S': // short
1768 case 'Z': // boolean
1770 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1771 // the VM spec:
1772 case 's':
1773 {
1774 // For the above tag values (including the BaseType values),
1775 // value.const_value_index is right union field.
1777 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1778 // not enough room for a const_value_index
1779 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1780 ("length() is too small for a const_value_index"));
1781 return false;
1782 }
1784 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1785 annotations_typeArray, byte_i_ref,
1786 "mapped old const_value_index=%d", THREAD);
1788 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1789 ("const_value_index=%d", const_value_index));
1790 } break;
1792 case 'e':
1793 {
1794 // for the above tag value, value.enum_const_value is right union field
1796 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1797 // not enough room for a enum_const_value
1798 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1799 ("length() is too small for a enum_const_value"));
1800 return false;
1801 }
1803 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1804 annotations_typeArray, byte_i_ref,
1805 "mapped old type_name_index=%d", THREAD);
1807 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1808 annotations_typeArray, byte_i_ref,
1809 "mapped old const_name_index=%d", THREAD);
1811 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1812 ("type_name_index=%d const_name_index=%d", type_name_index,
1813 const_name_index));
1814 } break;
1816 case 'c':
1817 {
1818 // for the above tag value, value.class_info_index is right union field
1820 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1821 // not enough room for a class_info_index
1822 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1823 ("length() is too small for a class_info_index"));
1824 return false;
1825 }
1827 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1828 annotations_typeArray, byte_i_ref,
1829 "mapped old class_info_index=%d", THREAD);
1831 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1832 ("class_info_index=%d", class_info_index));
1833 } break;
1835 case '@':
1836 // For the above tag value, value.attr_value is the right union
1837 // field. This is a nested annotation.
1838 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1839 byte_i_ref, THREAD)) {
1840 // propagate failure back to caller
1841 return false;
1842 }
1843 break;
1845 case '[':
1846 {
1847 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1848 // not enough room for a num_values field
1849 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1850 ("length() is too small for a num_values field"));
1851 return false;
1852 }
1854 // For the above tag value, value.array_value is the right union
1855 // field. This is an array of nested element_value.
1856 u2 num_values = Bytes::get_Java_u2((address)
1857 annotations_typeArray->byte_at_addr(byte_i_ref));
1858 byte_i_ref += 2;
1859 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1861 int calc_num_values = 0;
1862 for (; calc_num_values < num_values; calc_num_values++) {
1863 if (!rewrite_cp_refs_in_element_value(
1864 annotations_typeArray, byte_i_ref, THREAD)) {
1865 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1866 ("bad nested element_value at %d", calc_num_values));
1867 // propagate failure back to caller
1868 return false;
1869 }
1870 }
1871 assert(num_values == calc_num_values, "sanity check");
1872 } break;
1874 default:
1875 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1876 return false;
1877 } // end decode tag field
1879 return true;
1880 } // end rewrite_cp_refs_in_element_value()
1883 // Rewrite constant pool references in a fields_annotations field.
1884 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1885 instanceKlassHandle scratch_class, TRAPS) {
1887 objArrayHandle fields_annotations(THREAD,
1888 scratch_class->fields_annotations());
1890 if (fields_annotations.is_null() || fields_annotations->length() == 0) {
1891 // no fields_annotations so nothing to do
1892 return true;
1893 }
1895 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1896 ("fields_annotations length=%d", fields_annotations->length()));
1898 for (int i = 0; i < fields_annotations->length(); i++) {
1899 typeArrayHandle field_annotations(THREAD,
1900 (typeArrayOop)fields_annotations->obj_at(i));
1901 if (field_annotations.is_null() || field_annotations->length() == 0) {
1902 // this field does not have any annotations so skip it
1903 continue;
1904 }
1906 int byte_i = 0; // byte index into field_annotations
1907 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1908 THREAD)) {
1909 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1910 ("bad field_annotations at %d", i));
1911 // propagate failure back to caller
1912 return false;
1913 }
1914 }
1916 return true;
1917 } // end rewrite_cp_refs_in_fields_annotations()
1920 // Rewrite constant pool references in a methods_annotations field.
1921 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1922 instanceKlassHandle scratch_class, TRAPS) {
1924 objArrayHandle methods_annotations(THREAD,
1925 scratch_class->methods_annotations());
1927 if (methods_annotations.is_null() || methods_annotations->length() == 0) {
1928 // no methods_annotations so nothing to do
1929 return true;
1930 }
1932 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1933 ("methods_annotations length=%d", methods_annotations->length()));
1935 for (int i = 0; i < methods_annotations->length(); i++) {
1936 typeArrayHandle method_annotations(THREAD,
1937 (typeArrayOop)methods_annotations->obj_at(i));
1938 if (method_annotations.is_null() || method_annotations->length() == 0) {
1939 // this method does not have any annotations so skip it
1940 continue;
1941 }
1943 int byte_i = 0; // byte index into method_annotations
1944 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1945 THREAD)) {
1946 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1947 ("bad method_annotations at %d", i));
1948 // propagate failure back to caller
1949 return false;
1950 }
1951 }
1953 return true;
1954 } // end rewrite_cp_refs_in_methods_annotations()
1957 // Rewrite constant pool references in a methods_parameter_annotations
1958 // field. This "structure" is adapted from the
1959 // RuntimeVisibleParameterAnnotations_attribute described in section
1960 // 4.8.17 of the 2nd-edition of the VM spec:
1961 //
1962 // methods_parameter_annotations_typeArray {
1963 // u1 num_parameters;
1964 // {
1965 // u2 num_annotations;
1966 // annotation annotations[num_annotations];
1967 // } parameter_annotations[num_parameters];
1968 // }
1969 //
1970 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1971 instanceKlassHandle scratch_class, TRAPS) {
1973 objArrayHandle methods_parameter_annotations(THREAD,
1974 scratch_class->methods_parameter_annotations());
1976 if (methods_parameter_annotations.is_null()
1977 || methods_parameter_annotations->length() == 0) {
1978 // no methods_parameter_annotations so nothing to do
1979 return true;
1980 }
1982 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1983 ("methods_parameter_annotations length=%d",
1984 methods_parameter_annotations->length()));
1986 for (int i = 0; i < methods_parameter_annotations->length(); i++) {
1987 typeArrayHandle method_parameter_annotations(THREAD,
1988 (typeArrayOop)methods_parameter_annotations->obj_at(i));
1989 if (method_parameter_annotations.is_null()
1990 || method_parameter_annotations->length() == 0) {
1991 // this method does not have any parameter annotations so skip it
1992 continue;
1993 }
1995 if (method_parameter_annotations->length() < 1) {
1996 // not enough room for a num_parameters field
1997 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1998 ("length() is too small for a num_parameters field at %d", i));
1999 return false;
2000 }
2002 int byte_i = 0; // byte index into method_parameter_annotations
2004 u1 num_parameters = method_parameter_annotations->byte_at(byte_i);
2005 byte_i++;
2007 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2008 ("num_parameters=%d", num_parameters));
2010 int calc_num_parameters = 0;
2011 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2012 if (!rewrite_cp_refs_in_annotations_typeArray(
2013 method_parameter_annotations, byte_i, THREAD)) {
2014 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2015 ("bad method_parameter_annotations at %d", calc_num_parameters));
2016 // propagate failure back to caller
2017 return false;
2018 }
2019 }
2020 assert(num_parameters == calc_num_parameters, "sanity check");
2021 }
2023 return true;
2024 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2027 // Rewrite constant pool references in a methods_default_annotations
2028 // field. This "structure" is adapted from the AnnotationDefault_attribute
2029 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2030 //
2031 // methods_default_annotations_typeArray {
2032 // element_value default_value;
2033 // }
2034 //
2035 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2036 instanceKlassHandle scratch_class, TRAPS) {
2038 objArrayHandle methods_default_annotations(THREAD,
2039 scratch_class->methods_default_annotations());
2041 if (methods_default_annotations.is_null()
2042 || methods_default_annotations->length() == 0) {
2043 // no methods_default_annotations so nothing to do
2044 return true;
2045 }
2047 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2048 ("methods_default_annotations length=%d",
2049 methods_default_annotations->length()));
2051 for (int i = 0; i < methods_default_annotations->length(); i++) {
2052 typeArrayHandle method_default_annotations(THREAD,
2053 (typeArrayOop)methods_default_annotations->obj_at(i));
2054 if (method_default_annotations.is_null()
2055 || method_default_annotations->length() == 0) {
2056 // this method does not have any default annotations so skip it
2057 continue;
2058 }
2060 int byte_i = 0; // byte index into method_default_annotations
2062 if (!rewrite_cp_refs_in_element_value(
2063 method_default_annotations, byte_i, THREAD)) {
2064 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2065 ("bad default element_value at %d", i));
2066 // propagate failure back to caller
2067 return false;
2068 }
2069 }
2071 return true;
2072 } // end rewrite_cp_refs_in_methods_default_annotations()
2075 // Rewrite constant pool references in the method's stackmap table.
2076 // These "structures" are adapted from the StackMapTable_attribute that
2077 // is described in section 4.8.4 of the 6.0 version of the VM spec
2078 // (dated 2005.10.26):
2079 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2080 //
2081 // stack_map {
2082 // u2 number_of_entries;
2083 // stack_map_frame entries[number_of_entries];
2084 // }
2085 //
2086 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2087 methodHandle method, TRAPS) {
2089 if (!method->has_stackmap_table()) {
2090 return;
2091 }
2093 typeArrayOop stackmap_data = method->stackmap_data();
2094 address stackmap_p = (address)stackmap_data->byte_at_addr(0);
2095 address stackmap_end = stackmap_p + stackmap_data->length();
2097 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2098 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2099 stackmap_p += 2;
2101 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2102 ("number_of_entries=%u", number_of_entries));
2104 // walk through each stack_map_frame
2105 u2 calc_number_of_entries = 0;
2106 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2107 // The stack_map_frame structure is a u1 frame_type followed by
2108 // 0 or more bytes of data:
2109 //
2110 // union stack_map_frame {
2111 // same_frame;
2112 // same_locals_1_stack_item_frame;
2113 // same_locals_1_stack_item_frame_extended;
2114 // chop_frame;
2115 // same_frame_extended;
2116 // append_frame;
2117 // full_frame;
2118 // }
2120 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2121 // The Linux compiler does not like frame_type to be u1 or u2. It
2122 // issues the following warning for the first if-statement below:
2123 //
2124 // "warning: comparison is always true due to limited range of data type"
2125 //
2126 u4 frame_type = *stackmap_p;
2127 stackmap_p++;
2129 // same_frame {
2130 // u1 frame_type = SAME; /* 0-63 */
2131 // }
2132 if (frame_type >= 0 && frame_type <= 63) {
2133 // nothing more to do for same_frame
2134 }
2136 // same_locals_1_stack_item_frame {
2137 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2138 // verification_type_info stack[1];
2139 // }
2140 else if (frame_type >= 64 && frame_type <= 127) {
2141 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2142 calc_number_of_entries, frame_type, THREAD);
2143 }
2145 // reserved for future use
2146 else if (frame_type >= 128 && frame_type <= 246) {
2147 // nothing more to do for reserved frame_types
2148 }
2150 // same_locals_1_stack_item_frame_extended {
2151 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2152 // u2 offset_delta;
2153 // verification_type_info stack[1];
2154 // }
2155 else if (frame_type == 247) {
2156 stackmap_p += 2;
2157 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2158 calc_number_of_entries, frame_type, THREAD);
2159 }
2161 // chop_frame {
2162 // u1 frame_type = CHOP; /* 248-250 */
2163 // u2 offset_delta;
2164 // }
2165 else if (frame_type >= 248 && frame_type <= 250) {
2166 stackmap_p += 2;
2167 }
2169 // same_frame_extended {
2170 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2171 // u2 offset_delta;
2172 // }
2173 else if (frame_type == 251) {
2174 stackmap_p += 2;
2175 }
2177 // append_frame {
2178 // u1 frame_type = APPEND; /* 252-254 */
2179 // u2 offset_delta;
2180 // verification_type_info locals[frame_type - 251];
2181 // }
2182 else if (frame_type >= 252 && frame_type <= 254) {
2183 assert(stackmap_p + 2 <= stackmap_end,
2184 "no room for offset_delta");
2185 stackmap_p += 2;
2186 u1 len = frame_type - 251;
2187 for (u1 i = 0; i < len; i++) {
2188 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2189 calc_number_of_entries, frame_type, THREAD);
2190 }
2191 }
2193 // full_frame {
2194 // u1 frame_type = FULL_FRAME; /* 255 */
2195 // u2 offset_delta;
2196 // u2 number_of_locals;
2197 // verification_type_info locals[number_of_locals];
2198 // u2 number_of_stack_items;
2199 // verification_type_info stack[number_of_stack_items];
2200 // }
2201 else if (frame_type == 255) {
2202 assert(stackmap_p + 2 + 2 <= stackmap_end,
2203 "no room for smallest full_frame");
2204 stackmap_p += 2;
2206 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2207 stackmap_p += 2;
2209 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2210 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2211 calc_number_of_entries, frame_type, THREAD);
2212 }
2214 // Use the largest size for the number_of_stack_items, but only get
2215 // the right number of bytes.
2216 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2217 stackmap_p += 2;
2219 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2220 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2221 calc_number_of_entries, frame_type, THREAD);
2222 }
2223 }
2224 } // end while there is a stack_map_frame
2225 assert(number_of_entries == calc_number_of_entries, "sanity check");
2226 } // end rewrite_cp_refs_in_stack_map_table()
2229 // Rewrite constant pool references in the verification type info
2230 // portion of the method's stackmap table. These "structures" are
2231 // adapted from the StackMapTable_attribute that is described in
2232 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2233 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2234 //
2235 // The verification_type_info structure is a u1 tag followed by 0 or
2236 // more bytes of data:
2237 //
2238 // union verification_type_info {
2239 // Top_variable_info;
2240 // Integer_variable_info;
2241 // Float_variable_info;
2242 // Long_variable_info;
2243 // Double_variable_info;
2244 // Null_variable_info;
2245 // UninitializedThis_variable_info;
2246 // Object_variable_info;
2247 // Uninitialized_variable_info;
2248 // }
2249 //
2250 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2251 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2252 u1 frame_type, TRAPS) {
2254 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2255 u1 tag = *stackmap_p_ref;
2256 stackmap_p_ref++;
2258 switch (tag) {
2259 // Top_variable_info {
2260 // u1 tag = ITEM_Top; /* 0 */
2261 // }
2262 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2263 case 0: // fall through
2265 // Integer_variable_info {
2266 // u1 tag = ITEM_Integer; /* 1 */
2267 // }
2268 case ITEM_Integer: // fall through
2270 // Float_variable_info {
2271 // u1 tag = ITEM_Float; /* 2 */
2272 // }
2273 case ITEM_Float: // fall through
2275 // Double_variable_info {
2276 // u1 tag = ITEM_Double; /* 3 */
2277 // }
2278 case ITEM_Double: // fall through
2280 // Long_variable_info {
2281 // u1 tag = ITEM_Long; /* 4 */
2282 // }
2283 case ITEM_Long: // fall through
2285 // Null_variable_info {
2286 // u1 tag = ITEM_Null; /* 5 */
2287 // }
2288 case ITEM_Null: // fall through
2290 // UninitializedThis_variable_info {
2291 // u1 tag = ITEM_UninitializedThis; /* 6 */
2292 // }
2293 case ITEM_UninitializedThis:
2294 // nothing more to do for the above tag types
2295 break;
2297 // Object_variable_info {
2298 // u1 tag = ITEM_Object; /* 7 */
2299 // u2 cpool_index;
2300 // }
2301 case ITEM_Object:
2302 {
2303 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2304 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2305 u2 new_cp_index = find_new_index(cpool_index);
2306 if (new_cp_index != 0) {
2307 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2308 ("mapped old cpool_index=%d", cpool_index));
2309 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2310 cpool_index = new_cp_index;
2311 }
2312 stackmap_p_ref += 2;
2314 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2315 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2316 frame_type, cpool_index));
2317 } break;
2319 // Uninitialized_variable_info {
2320 // u1 tag = ITEM_Uninitialized; /* 8 */
2321 // u2 offset;
2322 // }
2323 case ITEM_Uninitialized:
2324 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2325 stackmap_p_ref += 2;
2326 break;
2328 default:
2329 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2330 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2331 ShouldNotReachHere();
2332 break;
2333 } // end switch (tag)
2334 } // end rewrite_cp_refs_in_verification_type_info()
2337 // Change the constant pool associated with klass scratch_class to
2338 // scratch_cp. If shrink is true, then scratch_cp_length elements
2339 // are copied from scratch_cp to a smaller constant pool and the
2340 // smaller constant pool is associated with scratch_class.
2341 void VM_RedefineClasses::set_new_constant_pool(
2342 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2343 int scratch_cp_length, bool shrink, TRAPS) {
2344 assert(!shrink || scratch_cp->length() >= scratch_cp_length, "sanity check");
2346 if (shrink) {
2347 // scratch_cp is a merged constant pool and has enough space for a
2348 // worst case merge situation. We want to associate the minimum
2349 // sized constant pool with the klass to save space.
2350 constantPoolHandle smaller_cp(THREAD,
2351 oopFactory::new_constantPool(scratch_cp_length,
2352 oopDesc::IsUnsafeConc,
2353 THREAD));
2354 // preserve orig_length() value in the smaller copy
2355 int orig_length = scratch_cp->orig_length();
2356 assert(orig_length != 0, "sanity check");
2357 smaller_cp->set_orig_length(orig_length);
2358 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2359 scratch_cp = smaller_cp;
2360 smaller_cp()->set_is_conc_safe(true);
2361 }
2363 // attach new constant pool to klass
2364 scratch_cp->set_pool_holder(scratch_class());
2366 // attach klass to new constant pool
2367 scratch_class->set_constants(scratch_cp());
2369 int i; // for portability
2371 // update each field in klass to use new constant pool indices as needed
2372 typeArrayHandle fields(THREAD, scratch_class->fields());
2373 int n_fields = fields->length();
2374 for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
2375 jshort cur_index = fields->short_at(i + instanceKlass::name_index_offset);
2376 jshort new_index = find_new_index(cur_index);
2377 if (new_index != 0) {
2378 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2379 ("field-name_index change: %d to %d", cur_index, new_index));
2380 fields->short_at_put(i + instanceKlass::name_index_offset, new_index);
2381 }
2382 cur_index = fields->short_at(i + instanceKlass::signature_index_offset);
2383 new_index = find_new_index(cur_index);
2384 if (new_index != 0) {
2385 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2386 ("field-signature_index change: %d to %d", cur_index, new_index));
2387 fields->short_at_put(i + instanceKlass::signature_index_offset,
2388 new_index);
2389 }
2390 cur_index = fields->short_at(i + instanceKlass::initval_index_offset);
2391 new_index = find_new_index(cur_index);
2392 if (new_index != 0) {
2393 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2394 ("field-initval_index change: %d to %d", cur_index, new_index));
2395 fields->short_at_put(i + instanceKlass::initval_index_offset, new_index);
2396 }
2397 cur_index = fields->short_at(i + instanceKlass::generic_signature_offset);
2398 new_index = find_new_index(cur_index);
2399 if (new_index != 0) {
2400 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2401 ("field-generic_signature change: %d to %d", cur_index, new_index));
2402 fields->short_at_put(i + instanceKlass::generic_signature_offset,
2403 new_index);
2404 }
2405 } // end for each field
2407 // Update constant pool indices in the inner classes info to use
2408 // new constant indices as needed. The inner classes info is a
2409 // quadruple:
2410 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2411 typeArrayOop inner_class_list = scratch_class->inner_classes();
2412 int icl_length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2413 if (icl_length > 0) {
2414 typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2415 for (int i = 0; i < icl_length;
2416 i += instanceKlass::inner_class_next_offset) {
2417 int cur_index = inner_class_list_h->ushort_at(i
2418 + instanceKlass::inner_class_inner_class_info_offset);
2419 if (cur_index == 0) {
2420 continue; // JVM spec. allows null inner class refs so skip it
2421 }
2422 int new_index = find_new_index(cur_index);
2423 if (new_index != 0) {
2424 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2425 ("inner_class_info change: %d to %d", cur_index, new_index));
2426 inner_class_list_h->ushort_at_put(i
2427 + instanceKlass::inner_class_inner_class_info_offset, new_index);
2428 }
2429 cur_index = inner_class_list_h->ushort_at(i
2430 + instanceKlass::inner_class_outer_class_info_offset);
2431 new_index = find_new_index(cur_index);
2432 if (new_index != 0) {
2433 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2434 ("outer_class_info change: %d to %d", cur_index, new_index));
2435 inner_class_list_h->ushort_at_put(i
2436 + instanceKlass::inner_class_outer_class_info_offset, new_index);
2437 }
2438 cur_index = inner_class_list_h->ushort_at(i
2439 + instanceKlass::inner_class_inner_name_offset);
2440 new_index = find_new_index(cur_index);
2441 if (new_index != 0) {
2442 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2443 ("inner_name change: %d to %d", cur_index, new_index));
2444 inner_class_list_h->ushort_at_put(i
2445 + instanceKlass::inner_class_inner_name_offset, new_index);
2446 }
2447 } // end for each inner class
2448 } // end if we have inner classes
2450 // Attach each method in klass to the new constant pool and update
2451 // to use new constant pool indices as needed:
2452 objArrayHandle methods(THREAD, scratch_class->methods());
2453 for (i = methods->length() - 1; i >= 0; i--) {
2454 methodHandle method(THREAD, (methodOop)methods->obj_at(i));
2455 method->set_constants(scratch_cp());
2457 int new_index = find_new_index(method->name_index());
2458 if (new_index != 0) {
2459 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2460 ("method-name_index change: %d to %d", method->name_index(),
2461 new_index));
2462 method->set_name_index(new_index);
2463 }
2464 new_index = find_new_index(method->signature_index());
2465 if (new_index != 0) {
2466 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2467 ("method-signature_index change: %d to %d",
2468 method->signature_index(), new_index));
2469 method->set_signature_index(new_index);
2470 }
2471 new_index = find_new_index(method->generic_signature_index());
2472 if (new_index != 0) {
2473 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2474 ("method-generic_signature_index change: %d to %d",
2475 method->generic_signature_index(), new_index));
2476 method->set_generic_signature_index(new_index);
2477 }
2479 // Update constant pool indices in the method's checked exception
2480 // table to use new constant indices as needed.
2481 int cext_length = method->checked_exceptions_length();
2482 if (cext_length > 0) {
2483 CheckedExceptionElement * cext_table =
2484 method->checked_exceptions_start();
2485 for (int j = 0; j < cext_length; j++) {
2486 int cur_index = cext_table[j].class_cp_index;
2487 int new_index = find_new_index(cur_index);
2488 if (new_index != 0) {
2489 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2490 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2491 cext_table[j].class_cp_index = (u2)new_index;
2492 }
2493 } // end for each checked exception table entry
2494 } // end if there are checked exception table entries
2496 // Update each catch type index in the method's exception table
2497 // to use new constant pool indices as needed. The exception table
2498 // holds quadruple entries of the form:
2499 // (beg_bci, end_bci, handler_bci, klass_index)
2500 const int beg_bci_offset = 0;
2501 const int end_bci_offset = 1;
2502 const int handler_bci_offset = 2;
2503 const int klass_index_offset = 3;
2504 const int entry_size = 4;
2506 typeArrayHandle ex_table (THREAD, method->exception_table());
2507 int ext_length = ex_table->length();
2508 assert(ext_length % entry_size == 0, "exception table format has changed");
2510 for (int j = 0; j < ext_length; j += entry_size) {
2511 int cur_index = ex_table->int_at(j + klass_index_offset);
2512 int new_index = find_new_index(cur_index);
2513 if (new_index != 0) {
2514 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2515 ("ext-klass_index change: %d to %d", cur_index, new_index));
2516 ex_table->int_at_put(j + klass_index_offset, new_index);
2517 }
2518 } // end for each exception table entry
2520 // Update constant pool indices in the method's local variable
2521 // table to use new constant indices as needed. The local variable
2522 // table hold sextuple entries of the form:
2523 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2524 int lvt_length = method->localvariable_table_length();
2525 if (lvt_length > 0) {
2526 LocalVariableTableElement * lv_table =
2527 method->localvariable_table_start();
2528 for (int j = 0; j < lvt_length; j++) {
2529 int cur_index = lv_table[j].name_cp_index;
2530 int new_index = find_new_index(cur_index);
2531 if (new_index != 0) {
2532 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2533 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2534 lv_table[j].name_cp_index = (u2)new_index;
2535 }
2536 cur_index = lv_table[j].descriptor_cp_index;
2537 new_index = find_new_index(cur_index);
2538 if (new_index != 0) {
2539 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2540 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2541 new_index));
2542 lv_table[j].descriptor_cp_index = (u2)new_index;
2543 }
2544 cur_index = lv_table[j].signature_cp_index;
2545 new_index = find_new_index(cur_index);
2546 if (new_index != 0) {
2547 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2548 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2549 lv_table[j].signature_cp_index = (u2)new_index;
2550 }
2551 } // end for each local variable table entry
2552 } // end if there are local variable table entries
2554 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2555 } // end for each method
2556 assert(scratch_cp()->is_conc_safe(), "Just checking");
2557 } // end set_new_constant_pool()
2560 // Unevolving classes may point to methods of the_class directly
2561 // from their constant pool caches, itables, and/or vtables. We
2562 // use the SystemDictionary::classes_do() facility and this helper
2563 // to fix up these pointers.
2564 //
2565 // Note: We currently don't support updating the vtable in
2566 // arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
2567 void VM_RedefineClasses::adjust_cpool_cache_and_vtable(klassOop k_oop,
2568 oop initiating_loader, TRAPS) {
2569 Klass *k = k_oop->klass_part();
2570 if (k->oop_is_instance()) {
2571 HandleMark hm(THREAD);
2572 instanceKlass *ik = (instanceKlass *) k;
2574 // HotSpot specific optimization! HotSpot does not currently
2575 // support delegation from the bootstrap class loader to a
2576 // user-defined class loader. This means that if the bootstrap
2577 // class loader is the initiating class loader, then it will also
2578 // be the defining class loader. This also means that classes
2579 // loaded by the bootstrap class loader cannot refer to classes
2580 // loaded by a user-defined class loader. Note: a user-defined
2581 // class loader can delegate to the bootstrap class loader.
2582 //
2583 // If the current class being redefined has a user-defined class
2584 // loader as its defining class loader, then we can skip all
2585 // classes loaded by the bootstrap class loader.
2586 bool is_user_defined =
2587 instanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2588 if (is_user_defined && ik->class_loader() == NULL) {
2589 return;
2590 }
2592 // This is a very busy routine. We don't want too much tracing
2593 // printed out.
2594 bool trace_name_printed = false;
2596 // Very noisy: only enable this call if you are trying to determine
2597 // that a specific class gets found by this routine.
2598 // RC_TRACE macro has an embedded ResourceMark
2599 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2600 // ("adjust check: name=%s", ik->external_name()));
2601 // trace_name_printed = true;
2603 // Fix the vtable embedded in the_class and subclasses of the_class,
2604 // if one exists. We discard scratch_class and we don't keep an
2605 // instanceKlass around to hold obsolete methods so we don't have
2606 // any other instanceKlass embedded vtables to update. The vtable
2607 // holds the methodOops for virtual (but not final) methods.
2608 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2609 // ik->vtable() creates a wrapper object; rm cleans it up
2610 ResourceMark rm(THREAD);
2611 ik->vtable()->adjust_method_entries(_matching_old_methods,
2612 _matching_new_methods,
2613 _matching_methods_length,
2614 &trace_name_printed);
2615 }
2617 // If the current class has an itable and we are either redefining an
2618 // interface or if the current class is a subclass of the_class, then
2619 // we potentially have to fix the itable. If we are redefining an
2620 // interface, then we have to call adjust_method_entries() for
2621 // every instanceKlass that has an itable since there isn't a
2622 // subclass relationship between an interface and an instanceKlass.
2623 if (ik->itable_length() > 0 && (Klass::cast(_the_class_oop)->is_interface()
2624 || ik->is_subclass_of(_the_class_oop))) {
2625 // ik->itable() creates a wrapper object; rm cleans it up
2626 ResourceMark rm(THREAD);
2627 ik->itable()->adjust_method_entries(_matching_old_methods,
2628 _matching_new_methods,
2629 _matching_methods_length,
2630 &trace_name_printed);
2631 }
2633 // The constant pools in other classes (other_cp) can refer to
2634 // methods in the_class. We have to update method information in
2635 // other_cp's cache. If other_cp has a previous version, then we
2636 // have to repeat the process for each previous version. The
2637 // constant pool cache holds the methodOops for non-virtual
2638 // methods and for virtual, final methods.
2639 //
2640 // Special case: if the current class is the_class, then new_cp
2641 // has already been attached to the_class and old_cp has already
2642 // been added as a previous version. The new_cp doesn't have any
2643 // cached references to old methods so it doesn't need to be
2644 // updated. We can simply start with the previous version(s) in
2645 // that case.
2646 constantPoolHandle other_cp;
2647 constantPoolCacheOop cp_cache;
2649 if (k_oop != _the_class_oop) {
2650 // this klass' constant pool cache may need adjustment
2651 other_cp = constantPoolHandle(ik->constants());
2652 cp_cache = other_cp->cache();
2653 if (cp_cache != NULL) {
2654 cp_cache->adjust_method_entries(_matching_old_methods,
2655 _matching_new_methods,
2656 _matching_methods_length,
2657 &trace_name_printed);
2658 }
2659 }
2660 {
2661 ResourceMark rm(THREAD);
2662 // PreviousVersionInfo objects returned via PreviousVersionWalker
2663 // contain a GrowableArray of handles. We have to clean up the
2664 // GrowableArray _after_ the PreviousVersionWalker destructor
2665 // has destroyed the handles.
2666 {
2667 // the previous versions' constant pool caches may need adjustment
2668 PreviousVersionWalker pvw(ik);
2669 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2670 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2671 other_cp = pv_info->prev_constant_pool_handle();
2672 cp_cache = other_cp->cache();
2673 if (cp_cache != NULL) {
2674 cp_cache->adjust_method_entries(_matching_old_methods,
2675 _matching_new_methods,
2676 _matching_methods_length,
2677 &trace_name_printed);
2678 }
2679 }
2680 } // pvw is cleaned up
2681 } // rm is cleaned up
2682 }
2683 }
2685 void VM_RedefineClasses::update_jmethod_ids() {
2686 for (int j = 0; j < _matching_methods_length; ++j) {
2687 methodOop old_method = _matching_old_methods[j];
2688 jmethodID jmid = old_method->find_jmethod_id_or_null();
2689 if (jmid != NULL) {
2690 // There is a jmethodID, change it to point to the new method
2691 methodHandle new_method_h(_matching_new_methods[j]);
2692 JNIHandles::change_method_associated_with_jmethod_id(jmid, new_method_h);
2693 assert(JNIHandles::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2694 "should be replaced");
2695 }
2696 }
2697 }
2699 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2700 BitMap *emcp_methods, int * emcp_method_count_p) {
2701 *emcp_method_count_p = 0;
2702 int obsolete_count = 0;
2703 int old_index = 0;
2704 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2705 methodOop old_method = _matching_old_methods[j];
2706 methodOop new_method = _matching_new_methods[j];
2707 methodOop old_array_method;
2709 // Maintain an old_index into the _old_methods array by skipping
2710 // deleted methods
2711 while ((old_array_method = (methodOop) _old_methods->obj_at(old_index))
2712 != old_method) {
2713 ++old_index;
2714 }
2716 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2717 // The EMCP definition from JSR-163 requires the bytecodes to be
2718 // the same with the exception of constant pool indices which may
2719 // differ. However, the constants referred to by those indices
2720 // must be the same.
2721 //
2722 // We use methods_EMCP() for comparison since constant pool
2723 // merging can remove duplicate constant pool entries that were
2724 // present in the old method and removed from the rewritten new
2725 // method. A faster binary comparison function would consider the
2726 // old and new methods to be different when they are actually
2727 // EMCP.
2728 //
2729 // The old and new methods are EMCP and you would think that we
2730 // could get rid of one of them here and now and save some space.
2731 // However, the concept of EMCP only considers the bytecodes and
2732 // the constant pool entries in the comparison. Other things,
2733 // e.g., the line number table (LNT) or the local variable table
2734 // (LVT) don't count in the comparison. So the new (and EMCP)
2735 // method can have a new LNT that we need so we can't just
2736 // overwrite the new method with the old method.
2737 //
2738 // When this routine is called, we have already attached the new
2739 // methods to the_class so the old methods are effectively
2740 // overwritten. However, if an old method is still executing,
2741 // then the old method cannot be collected until sometime after
2742 // the old method call has returned. So the overwriting of old
2743 // methods by new methods will save us space except for those
2744 // (hopefully few) old methods that are still executing.
2745 //
2746 // A method refers to a constMethodOop and this presents another
2747 // possible avenue to space savings. The constMethodOop in the
2748 // new method contains possibly new attributes (LNT, LVT, etc).
2749 // At first glance, it seems possible to save space by replacing
2750 // the constMethodOop in the old method with the constMethodOop
2751 // from the new method. The old and new methods would share the
2752 // same constMethodOop and we would save the space occupied by
2753 // the old constMethodOop. However, the constMethodOop contains
2754 // a back reference to the containing method. Sharing the
2755 // constMethodOop between two methods could lead to confusion in
2756 // the code that uses the back reference. This would lead to
2757 // brittle code that could be broken in non-obvious ways now or
2758 // in the future.
2759 //
2760 // Another possibility is to copy the constMethodOop from the new
2761 // method to the old method and then overwrite the new method with
2762 // the old method. Since the constMethodOop contains the bytecodes
2763 // for the method embedded in the oop, this option would change
2764 // the bytecodes out from under any threads executing the old
2765 // method and make the thread's bcp invalid. Since EMCP requires
2766 // that the bytecodes be the same modulo constant pool indices, it
2767 // is straight forward to compute the correct new bcp in the new
2768 // constMethodOop from the old bcp in the old constMethodOop. The
2769 // time consuming part would be searching all the frames in all
2770 // of the threads to find all of the calls to the old method.
2771 //
2772 // It looks like we will have to live with the limited savings
2773 // that we get from effectively overwriting the old methods
2774 // when the new methods are attached to the_class.
2776 // track which methods are EMCP for add_previous_version() call
2777 emcp_methods->set_bit(old_index);
2778 (*emcp_method_count_p)++;
2780 // An EMCP method is _not_ obsolete. An obsolete method has a
2781 // different jmethodID than the current method. An EMCP method
2782 // has the same jmethodID as the current method. Having the
2783 // same jmethodID for all EMCP versions of a method allows for
2784 // a consistent view of the EMCP methods regardless of which
2785 // EMCP method you happen to have in hand. For example, a
2786 // breakpoint set in one EMCP method will work for all EMCP
2787 // versions of the method including the current one.
2788 } else {
2789 // mark obsolete methods as such
2790 old_method->set_is_obsolete();
2791 obsolete_count++;
2793 // obsolete methods need a unique idnum
2794 u2 num = instanceKlass::cast(_the_class_oop)->next_method_idnum();
2795 if (num != constMethodOopDesc::UNSET_IDNUM) {
2796 // u2 old_num = old_method->method_idnum();
2797 old_method->set_method_idnum(num);
2798 // TO DO: attach obsolete annotations to obsolete method's new idnum
2799 }
2800 // With tracing we try not to "yack" too much. The position of
2801 // this trace assumes there are fewer obsolete methods than
2802 // EMCP methods.
2803 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2804 old_method->name()->as_C_string(),
2805 old_method->signature()->as_C_string()));
2806 }
2807 old_method->set_is_old();
2808 }
2809 for (int i = 0; i < _deleted_methods_length; ++i) {
2810 methodOop old_method = _deleted_methods[i];
2812 assert(old_method->vtable_index() < 0,
2813 "cannot delete methods with vtable entries");;
2815 // Mark all deleted methods as old and obsolete
2816 old_method->set_is_old();
2817 old_method->set_is_obsolete();
2818 ++obsolete_count;
2819 // With tracing we try not to "yack" too much. The position of
2820 // this trace assumes there are fewer obsolete methods than
2821 // EMCP methods.
2822 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2823 old_method->name()->as_C_string(),
2824 old_method->signature()->as_C_string()));
2825 }
2826 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2827 "sanity check");
2828 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2829 obsolete_count));
2830 }
2832 // This internal class transfers the native function registration from old methods
2833 // to new methods. It is designed to handle both the simple case of unchanged
2834 // native methods and the complex cases of native method prefixes being added and/or
2835 // removed.
2836 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2837 //
2838 // This class is used after the new methods have been installed in "the_class".
2839 //
2840 // So, for example, the following must be handled. Where 'm' is a method and
2841 // a number followed by an underscore is a prefix.
2842 //
2843 // Old Name New Name
2844 // Simple transfer to new method m -> m
2845 // Add prefix m -> 1_m
2846 // Remove prefix 1_m -> m
2847 // Simultaneous add of prefixes m -> 3_2_1_m
2848 // Simultaneous removal of prefixes 3_2_1_m -> m
2849 // Simultaneous add and remove 1_m -> 2_m
2850 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2851 //
2852 class TransferNativeFunctionRegistration {
2853 private:
2854 instanceKlassHandle the_class;
2855 int prefix_count;
2856 char** prefixes;
2858 // Recursively search the binary tree of possibly prefixed method names.
2859 // Iteration could be used if all agents were well behaved. Full tree walk is
2860 // more resilent to agents not cleaning up intermediate methods.
2861 // Branch at each depth in the binary tree is:
2862 // (1) without the prefix.
2863 // (2) with the prefix.
2864 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2865 methodOop search_prefix_name_space(int depth, char* name_str, size_t name_len,
2866 Symbol* signature) {
2867 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2868 if (name_symbol != NULL) {
2869 methodOop method = Klass::cast(the_class())->lookup_method(name_symbol, signature);
2870 if (method != NULL) {
2871 // Even if prefixed, intermediate methods must exist.
2872 if (method->is_native()) {
2873 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2874 return method;
2875 }
2876 if (depth < prefix_count) {
2877 // Try applying further prefixes (other than this one).
2878 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2879 if (method != NULL) {
2880 return method; // found
2881 }
2883 // Try adding this prefix to the method name and see if it matches
2884 // another method name.
2885 char* prefix = prefixes[depth];
2886 size_t prefix_len = strlen(prefix);
2887 size_t trial_len = name_len + prefix_len;
2888 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2889 strcpy(trial_name_str, prefix);
2890 strcat(trial_name_str, name_str);
2891 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2892 signature);
2893 if (method != NULL) {
2894 // If found along this branch, it was prefixed, mark as such
2895 method->set_is_prefixed_native();
2896 return method; // found
2897 }
2898 }
2899 }
2900 }
2901 return NULL; // This whole branch bore nothing
2902 }
2904 // Return the method name with old prefixes stripped away.
2905 char* method_name_without_prefixes(methodOop method) {
2906 Symbol* name = method->name();
2907 char* name_str = name->as_utf8();
2909 // Old prefixing may be defunct, strip prefixes, if any.
2910 for (int i = prefix_count-1; i >= 0; i--) {
2911 char* prefix = prefixes[i];
2912 size_t prefix_len = strlen(prefix);
2913 if (strncmp(prefix, name_str, prefix_len) == 0) {
2914 name_str += prefix_len;
2915 }
2916 }
2917 return name_str;
2918 }
2920 // Strip any prefixes off the old native method, then try to find a
2921 // (possibly prefixed) new native that matches it.
2922 methodOop strip_and_search_for_new_native(methodOop method) {
2923 ResourceMark rm;
2924 char* name_str = method_name_without_prefixes(method);
2925 return search_prefix_name_space(0, name_str, strlen(name_str),
2926 method->signature());
2927 }
2929 public:
2931 // Construct a native method transfer processor for this class.
2932 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
2933 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
2935 the_class = _the_class;
2936 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
2937 }
2939 // Attempt to transfer any of the old or deleted methods that are native
2940 void transfer_registrations(methodOop* old_methods, int methods_length) {
2941 for (int j = 0; j < methods_length; j++) {
2942 methodOop old_method = old_methods[j];
2944 if (old_method->is_native() && old_method->has_native_function()) {
2945 methodOop new_method = strip_and_search_for_new_native(old_method);
2946 if (new_method != NULL) {
2947 // Actually set the native function in the new method.
2948 // Redefine does not send events (except CFLH), certainly not this
2949 // behind the scenes re-registration.
2950 new_method->set_native_function(old_method->native_function(),
2951 !methodOopDesc::native_bind_event_is_interesting);
2952 }
2953 }
2954 }
2955 }
2956 };
2958 // Don't lose the association between a native method and its JNI function.
2959 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
2960 TransferNativeFunctionRegistration transfer(the_class);
2961 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
2962 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
2963 }
2965 // Deoptimize all compiled code that depends on this class.
2966 //
2967 // If the can_redefine_classes capability is obtained in the onload
2968 // phase then the compiler has recorded all dependencies from startup.
2969 // In that case we need only deoptimize and throw away all compiled code
2970 // that depends on the class.
2971 //
2972 // If can_redefine_classes is obtained sometime after the onload
2973 // phase then the dependency information may be incomplete. In that case
2974 // the first call to RedefineClasses causes all compiled code to be
2975 // thrown away. As can_redefine_classes has been obtained then
2976 // all future compilations will record dependencies so second and
2977 // subsequent calls to RedefineClasses need only throw away code
2978 // that depends on the class.
2979 //
2980 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
2981 assert_locked_or_safepoint(Compile_lock);
2983 // All dependencies have been recorded from startup or this is a second or
2984 // subsequent use of RedefineClasses
2985 if (JvmtiExport::all_dependencies_are_recorded()) {
2986 Universe::flush_evol_dependents_on(k_h);
2987 } else {
2988 CodeCache::mark_all_nmethods_for_deoptimization();
2990 ResourceMark rm(THREAD);
2991 DeoptimizationMarker dm;
2993 // Deoptimize all activations depending on marked nmethods
2994 Deoptimization::deoptimize_dependents();
2996 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
2997 CodeCache::make_marked_nmethods_not_entrant();
2999 // From now on we know that the dependency information is complete
3000 JvmtiExport::set_all_dependencies_are_recorded(true);
3001 }
3002 }
3004 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3005 methodOop old_method;
3006 methodOop new_method;
3008 _matching_old_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3009 _matching_new_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3010 _added_methods = NEW_RESOURCE_ARRAY(methodOop, _new_methods->length());
3011 _deleted_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
3013 _matching_methods_length = 0;
3014 _deleted_methods_length = 0;
3015 _added_methods_length = 0;
3017 int nj = 0;
3018 int oj = 0;
3019 while (true) {
3020 if (oj >= _old_methods->length()) {
3021 if (nj >= _new_methods->length()) {
3022 break; // we've looked at everything, done
3023 }
3024 // New method at the end
3025 new_method = (methodOop) _new_methods->obj_at(nj);
3026 _added_methods[_added_methods_length++] = new_method;
3027 ++nj;
3028 } else if (nj >= _new_methods->length()) {
3029 // Old method, at the end, is deleted
3030 old_method = (methodOop) _old_methods->obj_at(oj);
3031 _deleted_methods[_deleted_methods_length++] = old_method;
3032 ++oj;
3033 } else {
3034 old_method = (methodOop) _old_methods->obj_at(oj);
3035 new_method = (methodOop) _new_methods->obj_at(nj);
3036 if (old_method->name() == new_method->name()) {
3037 if (old_method->signature() == new_method->signature()) {
3038 _matching_old_methods[_matching_methods_length ] = old_method;
3039 _matching_new_methods[_matching_methods_length++] = new_method;
3040 ++nj;
3041 ++oj;
3042 } else {
3043 // added overloaded have already been moved to the end,
3044 // so this is a deleted overloaded method
3045 _deleted_methods[_deleted_methods_length++] = old_method;
3046 ++oj;
3047 }
3048 } else { // names don't match
3049 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3050 // new method
3051 _added_methods[_added_methods_length++] = new_method;
3052 ++nj;
3053 } else {
3054 // deleted method
3055 _deleted_methods[_deleted_methods_length++] = old_method;
3056 ++oj;
3057 }
3058 }
3059 }
3060 }
3061 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3062 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3063 }
3067 // Install the redefinition of a class:
3068 // - house keeping (flushing breakpoints and caches, deoptimizing
3069 // dependent compiled code)
3070 // - replacing parts in the_class with parts from scratch_class
3071 // - adding a weak reference to track the obsolete but interesting
3072 // parts of the_class
3073 // - adjusting constant pool caches and vtables in other classes
3074 // that refer to methods in the_class. These adjustments use the
3075 // SystemDictionary::classes_do() facility which only allows
3076 // a helper method to be specified. The interesting parameters
3077 // that we would like to pass to the helper method are saved in
3078 // static global fields in the VM operation.
3079 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3080 instanceKlassHandle scratch_class, TRAPS) {
3082 RC_TIMER_START(_timer_rsc_phase1);
3084 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3085 klassOop the_class_oop = java_lang_Class::as_klassOop(the_class_mirror);
3086 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3088 #ifndef JVMTI_KERNEL
3089 // Remove all breakpoints in methods of this class
3090 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3091 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3092 #endif // !JVMTI_KERNEL
3094 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3095 // We are redefining java.lang.reflect.Method. Method.invoke() is
3096 // cached and users of the cache care about each active version of
3097 // the method so we have to track this previous version.
3098 // Do this before methods get switched
3099 Universe::reflect_invoke_cache()->add_previous_version(
3100 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3101 }
3103 // Deoptimize all compiled code that depends on this class
3104 flush_dependent_code(the_class, THREAD);
3106 _old_methods = the_class->methods();
3107 _new_methods = scratch_class->methods();
3108 _the_class_oop = the_class_oop;
3109 compute_added_deleted_matching_methods();
3110 update_jmethod_ids();
3112 // Attach new constant pool to the original klass. The original
3113 // klass still refers to the old constant pool (for now).
3114 scratch_class->constants()->set_pool_holder(the_class());
3116 #if 0
3117 // In theory, with constant pool merging in place we should be able
3118 // to save space by using the new, merged constant pool in place of
3119 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3120 // the klass version we are replacing now and any constant pool(s) in
3121 // previous versions of klass. Nice theory, doesn't work in practice.
3122 // When this code is enabled, even simple programs throw NullPointer
3123 // exceptions. I'm guessing that this is caused by some constant pool
3124 // cache difference between the new, merged constant pool and the
3125 // constant pool that was just being used by the klass. I'm keeping
3126 // this code around to archive the idea, but the code has to remain
3127 // disabled for now.
3129 // Attach each old method to the new constant pool. This can be
3130 // done here since we are past the bytecode verification and
3131 // constant pool optimization phases.
3132 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3133 methodOop method = (methodOop)_old_methods->obj_at(i);
3134 method->set_constants(scratch_class->constants());
3135 }
3137 {
3138 // walk all previous versions of the klass
3139 instanceKlass *ik = (instanceKlass *)the_class()->klass_part();
3140 PreviousVersionWalker pvw(ik);
3141 instanceKlassHandle ikh;
3142 do {
3143 ikh = pvw.next_previous_version();
3144 if (!ikh.is_null()) {
3145 ik = ikh();
3147 // attach previous version of klass to the new constant pool
3148 ik->set_constants(scratch_class->constants());
3150 // Attach each method in the previous version of klass to the
3151 // new constant pool
3152 objArrayOop prev_methods = ik->methods();
3153 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3154 methodOop method = (methodOop)prev_methods->obj_at(i);
3155 method->set_constants(scratch_class->constants());
3156 }
3157 }
3158 } while (!ikh.is_null());
3159 }
3160 #endif
3162 // Replace methods and constantpool
3163 the_class->set_methods(_new_methods);
3164 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3165 // and to be able to undo operation easily.
3167 constantPoolOop old_constants = the_class->constants();
3168 the_class->set_constants(scratch_class->constants());
3169 scratch_class->set_constants(old_constants); // See the previous comment.
3170 #if 0
3171 // We are swapping the guts of "the new class" with the guts of "the
3172 // class". Since the old constant pool has just been attached to "the
3173 // new class", it seems logical to set the pool holder in the old
3174 // constant pool also. However, doing this will change the observable
3175 // class hierarchy for any old methods that are still executing. A
3176 // method can query the identity of its "holder" and this query uses
3177 // the method's constant pool link to find the holder. The change in
3178 // holding class from "the class" to "the new class" can confuse
3179 // things.
3180 //
3181 // Setting the old constant pool's holder will also cause
3182 // verification done during vtable initialization below to fail.
3183 // During vtable initialization, the vtable's class is verified to be
3184 // a subtype of the method's holder. The vtable's class is "the
3185 // class" and the method's holder is gotten from the constant pool
3186 // link in the method itself. For "the class"'s directly implemented
3187 // methods, the method holder is "the class" itself (as gotten from
3188 // the new constant pool). The check works fine in this case. The
3189 // check also works fine for methods inherited from super classes.
3190 //
3191 // Miranda methods are a little more complicated. A miranda method is
3192 // provided by an interface when the class implementing the interface
3193 // does not provide its own method. These interfaces are implemented
3194 // internally as an instanceKlass. These special instanceKlasses
3195 // share the constant pool of the class that "implements" the
3196 // interface. By sharing the constant pool, the method holder of a
3197 // miranda method is the class that "implements" the interface. In a
3198 // non-redefine situation, the subtype check works fine. However, if
3199 // the old constant pool's pool holder is modified, then the check
3200 // fails because there is no class hierarchy relationship between the
3201 // vtable's class and "the new class".
3203 old_constants->set_pool_holder(scratch_class());
3204 #endif
3206 // track which methods are EMCP for add_previous_version() call below
3207 BitMap emcp_methods(_old_methods->length());
3208 int emcp_method_count = 0;
3209 emcp_methods.clear(); // clears 0..(length() - 1)
3210 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3211 transfer_old_native_function_registrations(the_class);
3213 // The class file bytes from before any retransformable agents mucked
3214 // with them was cached on the scratch class, move to the_class.
3215 // Note: we still want to do this if nothing needed caching since it
3216 // should get cleared in the_class too.
3217 the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(),
3218 scratch_class->get_cached_class_file_len());
3220 // Replace inner_classes
3221 typeArrayOop old_inner_classes = the_class->inner_classes();
3222 the_class->set_inner_classes(scratch_class->inner_classes());
3223 scratch_class->set_inner_classes(old_inner_classes);
3225 // Initialize the vtable and interface table after
3226 // methods have been rewritten
3227 {
3228 ResourceMark rm(THREAD);
3229 // no exception should happen here since we explicitly
3230 // do not check loader constraints.
3231 // compare_and_normalize_class_versions has already checked:
3232 // - classloaders unchanged, signatures unchanged
3233 // - all instanceKlasses for redefined classes reused & contents updated
3234 the_class->vtable()->initialize_vtable(false, THREAD);
3235 the_class->itable()->initialize_itable(false, THREAD);
3236 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3237 }
3239 // Leave arrays of jmethodIDs and itable index cache unchanged
3241 // Copy the "source file name" attribute from new class version
3242 the_class->set_source_file_name(scratch_class->source_file_name());
3244 // Copy the "source debug extension" attribute from new class version
3245 the_class->set_source_debug_extension(
3246 scratch_class->source_debug_extension());
3248 // Use of javac -g could be different in the old and the new
3249 if (scratch_class->access_flags().has_localvariable_table() !=
3250 the_class->access_flags().has_localvariable_table()) {
3252 AccessFlags flags = the_class->access_flags();
3253 if (scratch_class->access_flags().has_localvariable_table()) {
3254 flags.set_has_localvariable_table();
3255 } else {
3256 flags.clear_has_localvariable_table();
3257 }
3258 the_class->set_access_flags(flags);
3259 }
3261 // Replace class annotation fields values
3262 typeArrayOop old_class_annotations = the_class->class_annotations();
3263 the_class->set_class_annotations(scratch_class->class_annotations());
3264 scratch_class->set_class_annotations(old_class_annotations);
3266 // Replace fields annotation fields values
3267 objArrayOop old_fields_annotations = the_class->fields_annotations();
3268 the_class->set_fields_annotations(scratch_class->fields_annotations());
3269 scratch_class->set_fields_annotations(old_fields_annotations);
3271 // Replace methods annotation fields values
3272 objArrayOop old_methods_annotations = the_class->methods_annotations();
3273 the_class->set_methods_annotations(scratch_class->methods_annotations());
3274 scratch_class->set_methods_annotations(old_methods_annotations);
3276 // Replace methods parameter annotation fields values
3277 objArrayOop old_methods_parameter_annotations =
3278 the_class->methods_parameter_annotations();
3279 the_class->set_methods_parameter_annotations(
3280 scratch_class->methods_parameter_annotations());
3281 scratch_class->set_methods_parameter_annotations(old_methods_parameter_annotations);
3283 // Replace methods default annotation fields values
3284 objArrayOop old_methods_default_annotations =
3285 the_class->methods_default_annotations();
3286 the_class->set_methods_default_annotations(
3287 scratch_class->methods_default_annotations());
3288 scratch_class->set_methods_default_annotations(old_methods_default_annotations);
3290 // Replace minor version number of class file
3291 u2 old_minor_version = the_class->minor_version();
3292 the_class->set_minor_version(scratch_class->minor_version());
3293 scratch_class->set_minor_version(old_minor_version);
3295 // Replace major version number of class file
3296 u2 old_major_version = the_class->major_version();
3297 the_class->set_major_version(scratch_class->major_version());
3298 scratch_class->set_major_version(old_major_version);
3300 // Replace CP indexes for class and name+type of enclosing method
3301 u2 old_class_idx = the_class->enclosing_method_class_index();
3302 u2 old_method_idx = the_class->enclosing_method_method_index();
3303 the_class->set_enclosing_method_indices(
3304 scratch_class->enclosing_method_class_index(),
3305 scratch_class->enclosing_method_method_index());
3306 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3308 // keep track of previous versions of this class
3309 the_class->add_previous_version(scratch_class, &emcp_methods,
3310 emcp_method_count);
3312 RC_TIMER_STOP(_timer_rsc_phase1);
3313 RC_TIMER_START(_timer_rsc_phase2);
3315 // Adjust constantpool caches and vtables for all classes
3316 // that reference methods of the evolved class.
3317 SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
3319 if (the_class->oop_map_cache() != NULL) {
3320 // Flush references to any obsolete methods from the oop map cache
3321 // so that obsolete methods are not pinned.
3322 the_class->oop_map_cache()->flush_obsolete_entries();
3323 }
3325 // increment the classRedefinedCount field in the_class and in any
3326 // direct and indirect subclasses of the_class
3327 increment_class_counter((instanceKlass *)the_class()->klass_part(), THREAD);
3329 // RC_TRACE macro has an embedded ResourceMark
3330 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3331 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3332 the_class->external_name(),
3333 java_lang_Class::classRedefinedCount(the_class_mirror),
3334 os::available_memory() >> 10));
3336 RC_TIMER_STOP(_timer_rsc_phase2);
3337 } // end redefine_single_class()
3340 // Increment the classRedefinedCount field in the specific instanceKlass
3341 // and in all direct and indirect subclasses.
3342 void VM_RedefineClasses::increment_class_counter(instanceKlass *ik, TRAPS) {
3343 oop class_mirror = ik->java_mirror();
3344 klassOop class_oop = java_lang_Class::as_klassOop(class_mirror);
3345 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3346 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3348 if (class_oop != _the_class_oop) {
3349 // _the_class_oop count is printed at end of redefine_single_class()
3350 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3351 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3352 }
3354 for (Klass *subk = ik->subklass(); subk != NULL;
3355 subk = subk->next_sibling()) {
3356 if (subk->oop_is_instance()) {
3357 // Only update instanceKlasses
3358 instanceKlass *subik = (instanceKlass*)subk;
3359 // recursively do subclasses of the current subclass
3360 increment_class_counter(subik, THREAD);
3361 }
3362 }
3363 }
3365 #ifndef PRODUCT
3366 void VM_RedefineClasses::check_class(klassOop k_oop,
3367 oop initiating_loader, TRAPS) {
3368 Klass *k = k_oop->klass_part();
3369 if (k->oop_is_instance()) {
3370 HandleMark hm(THREAD);
3371 instanceKlass *ik = (instanceKlass *) k;
3373 if (ik->vtable_length() > 0) {
3374 ResourceMark rm(THREAD);
3375 if (!ik->vtable()->check_no_old_entries()) {
3376 tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
3377 ik->vtable()->dump_vtable();
3378 dump_methods();
3379 assert(false, "OLD method found");
3380 }
3381 }
3382 }
3383 }
3385 void VM_RedefineClasses::dump_methods() {
3386 int j;
3387 tty->print_cr("_old_methods --");
3388 for (j = 0; j < _old_methods->length(); ++j) {
3389 methodOop m = (methodOop) _old_methods->obj_at(j);
3390 tty->print("%4d (%5d) ", j, m->vtable_index());
3391 m->access_flags().print_on(tty);
3392 tty->print(" -- ");
3393 m->print_name(tty);
3394 tty->cr();
3395 }
3396 tty->print_cr("_new_methods --");
3397 for (j = 0; j < _new_methods->length(); ++j) {
3398 methodOop m = (methodOop) _new_methods->obj_at(j);
3399 tty->print("%4d (%5d) ", j, m->vtable_index());
3400 m->access_flags().print_on(tty);
3401 tty->print(" -- ");
3402 m->print_name(tty);
3403 tty->cr();
3404 }
3405 tty->print_cr("_matching_(old/new)_methods --");
3406 for (j = 0; j < _matching_methods_length; ++j) {
3407 methodOop m = _matching_old_methods[j];
3408 tty->print("%4d (%5d) ", j, m->vtable_index());
3409 m->access_flags().print_on(tty);
3410 tty->print(" -- ");
3411 m->print_name(tty);
3412 tty->cr();
3413 m = _matching_new_methods[j];
3414 tty->print(" (%5d) ", m->vtable_index());
3415 m->access_flags().print_on(tty);
3416 tty->cr();
3417 }
3418 tty->print_cr("_deleted_methods --");
3419 for (j = 0; j < _deleted_methods_length; ++j) {
3420 methodOop m = _deleted_methods[j];
3421 tty->print("%4d (%5d) ", j, m->vtable_index());
3422 m->access_flags().print_on(tty);
3423 tty->print(" -- ");
3424 m->print_name(tty);
3425 tty->cr();
3426 }
3427 tty->print_cr("_added_methods --");
3428 for (j = 0; j < _added_methods_length; ++j) {
3429 methodOop m = _added_methods[j];
3430 tty->print("%4d (%5d) ", j, m->vtable_index());
3431 m->access_flags().print_on(tty);
3432 tty->print(" -- ");
3433 m->print_name(tty);
3434 tty->cr();
3435 }
3436 }
3437 #endif