Mon, 13 May 2013 15:37:08 -0400
8005056: NPG: Crash after redefining java.lang.Object
Summary: Need to walk array class vtables replacing old methods too if j.l.o redefined
Reviewed-by: sspitsyn, dcubed, ctornqvi
1 /*
2 * Copyright (c) 2003, 2013, 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/metadataOnStackMark.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "interpreter/oopMapCache.hpp"
32 #include "interpreter/rewriter.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/klassVtable.hpp"
39 #include "prims/jvmtiImpl.hpp"
40 #include "prims/jvmtiRedefineClasses.hpp"
41 #include "prims/methodComparator.hpp"
42 #include "runtime/deoptimization.hpp"
43 #include "runtime/relocator.hpp"
44 #include "utilities/bitMap.inline.hpp"
47 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
48 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
49 Method** VM_RedefineClasses::_matching_old_methods = NULL;
50 Method** VM_RedefineClasses::_matching_new_methods = NULL;
51 Method** VM_RedefineClasses::_deleted_methods = NULL;
52 Method** VM_RedefineClasses::_added_methods = NULL;
53 int VM_RedefineClasses::_matching_methods_length = 0;
54 int VM_RedefineClasses::_deleted_methods_length = 0;
55 int VM_RedefineClasses::_added_methods_length = 0;
56 Klass* VM_RedefineClasses::_the_class_oop = NULL;
59 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
60 const jvmtiClassDefinition *class_defs,
61 JvmtiClassLoadKind class_load_kind) {
62 _class_count = class_count;
63 _class_defs = class_defs;
64 _class_load_kind = class_load_kind;
65 _res = JVMTI_ERROR_NONE;
66 }
68 bool VM_RedefineClasses::doit_prologue() {
69 if (_class_count == 0) {
70 _res = JVMTI_ERROR_NONE;
71 return false;
72 }
73 if (_class_defs == NULL) {
74 _res = JVMTI_ERROR_NULL_POINTER;
75 return false;
76 }
77 for (int i = 0; i < _class_count; i++) {
78 if (_class_defs[i].klass == NULL) {
79 _res = JVMTI_ERROR_INVALID_CLASS;
80 return false;
81 }
82 if (_class_defs[i].class_byte_count == 0) {
83 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
84 return false;
85 }
86 if (_class_defs[i].class_bytes == NULL) {
87 _res = JVMTI_ERROR_NULL_POINTER;
88 return false;
89 }
90 }
92 // Start timer after all the sanity checks; not quite accurate, but
93 // better than adding a bunch of stop() calls.
94 RC_TIMER_START(_timer_vm_op_prologue);
96 // We first load new class versions in the prologue, because somewhere down the
97 // call chain it is required that the current thread is a Java thread.
98 _res = load_new_class_versions(Thread::current());
99 if (_res != JVMTI_ERROR_NONE) {
100 // free any successfully created classes, since none are redefined
101 for (int i = 0; i < _class_count; i++) {
102 if (_scratch_classes[i] != NULL) {
103 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
104 // Free the memory for this class at class unloading time. Not before
105 // because CMS might think this is still live.
106 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
107 }
108 }
109 // Free os::malloc allocated memory in load_new_class_version.
110 os::free(_scratch_classes);
111 RC_TIMER_STOP(_timer_vm_op_prologue);
112 return false;
113 }
115 RC_TIMER_STOP(_timer_vm_op_prologue);
116 return true;
117 }
119 void VM_RedefineClasses::doit() {
120 Thread *thread = Thread::current();
122 if (UseSharedSpaces) {
123 // Sharing is enabled so we remap the shared readonly space to
124 // shared readwrite, private just in case we need to redefine
125 // a shared class. We do the remap during the doit() phase of
126 // the safepoint to be safer.
127 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
128 RC_TRACE_WITH_THREAD(0x00000001, thread,
129 ("failed to remap shared readonly space to readwrite, private"));
130 _res = JVMTI_ERROR_INTERNAL;
131 return;
132 }
133 }
135 // Mark methods seen on stack and everywhere else so old methods are not
136 // cleaned up if they're on the stack.
137 MetadataOnStackMark md_on_stack;
138 HandleMark hm(thread); // make sure any handles created are deleted
139 // before the stack walk again.
141 for (int i = 0; i < _class_count; i++) {
142 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
143 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
144 // Free the memory for this class at class unloading time. Not before
145 // because CMS might think this is still live.
146 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
147 _scratch_classes[i] = NULL;
148 }
150 // Disable any dependent concurrent compilations
151 SystemDictionary::notice_modification();
153 // Set flag indicating that some invariants are no longer true.
154 // See jvmtiExport.hpp for detailed explanation.
155 JvmtiExport::set_has_redefined_a_class();
157 // check_class() is optionally called for product bits, but is
158 // always called for non-product bits.
159 #ifdef PRODUCT
160 if (RC_TRACE_ENABLED(0x00004000)) {
161 #endif
162 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
163 CheckClass check_class(thread);
164 ClassLoaderDataGraph::classes_do(&check_class);
165 #ifdef PRODUCT
166 }
167 #endif
168 }
170 void VM_RedefineClasses::doit_epilogue() {
171 // Free os::malloc allocated memory.
172 os::free(_scratch_classes);
174 if (RC_TRACE_ENABLED(0x00000004)) {
175 // Used to have separate timers for "doit" and "all", but the timer
176 // overhead skewed the measurements.
177 jlong doit_time = _timer_rsc_phase1.milliseconds() +
178 _timer_rsc_phase2.milliseconds();
179 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
181 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
182 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
183 _timer_vm_op_prologue.milliseconds(), doit_time));
184 RC_TRACE(0x00000004,
185 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
186 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
187 }
188 }
190 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
191 // classes for primitives cannot be redefined
192 if (java_lang_Class::is_primitive(klass_mirror)) {
193 return false;
194 }
195 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
196 // classes for arrays cannot be redefined
197 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
198 return false;
199 }
200 return true;
201 }
203 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
204 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
205 // direct CP entries, there is just the current entry to append. For
206 // indirect and double-indirect CP entries, there are zero or more
207 // referenced CP entries along with the current entry to append.
208 // Indirect and double-indirect CP entries are handled by recursive
209 // calls to append_entry() as needed. The referenced CP entries are
210 // always appended to *merge_cp_p before the referee CP entry. These
211 // referenced CP entries may already exist in *merge_cp_p in which case
212 // there is nothing extra to append and only the current entry is
213 // appended.
214 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
215 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
216 TRAPS) {
218 // append is different depending on entry tag type
219 switch (scratch_cp->tag_at(scratch_i).value()) {
221 // The old verifier is implemented outside the VM. It loads classes,
222 // but does not resolve constant pool entries directly so we never
223 // see Class entries here with the old verifier. Similarly the old
224 // verifier does not like Class entries in the input constant pool.
225 // The split-verifier is implemented in the VM so it can optionally
226 // and directly resolve constant pool entries to load classes. The
227 // split-verifier can accept either Class entries or UnresolvedClass
228 // entries in the input constant pool. We revert the appended copy
229 // back to UnresolvedClass so that either verifier will be happy
230 // with the constant pool entry.
231 case JVM_CONSTANT_Class:
232 {
233 // revert the copy to JVM_CONSTANT_UnresolvedClass
234 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
235 scratch_cp->klass_name_at(scratch_i));
237 if (scratch_i != *merge_cp_length_p) {
238 // The new entry in *merge_cp_p is at a different index than
239 // the new entry in scratch_cp so we need to map the index values.
240 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
241 }
242 (*merge_cp_length_p)++;
243 } break;
245 // these are direct CP entries so they can be directly appended,
246 // but double and long take two constant pool entries
247 case JVM_CONSTANT_Double: // fall through
248 case JVM_CONSTANT_Long:
249 {
250 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
251 THREAD);
253 if (scratch_i != *merge_cp_length_p) {
254 // The new entry in *merge_cp_p is at a different index than
255 // the new entry in scratch_cp so we need to map the index values.
256 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
257 }
258 (*merge_cp_length_p) += 2;
259 } break;
261 // these are direct CP entries so they can be directly appended
262 case JVM_CONSTANT_Float: // fall through
263 case JVM_CONSTANT_Integer: // fall through
264 case JVM_CONSTANT_Utf8: // fall through
266 // This was an indirect CP entry, but it has been changed into
267 // Symbol*s so this entry can be directly appended.
268 case JVM_CONSTANT_String: // fall through
270 // These were indirect CP entries, but they have been changed into
271 // Symbol*s so these entries can be directly appended.
272 case JVM_CONSTANT_UnresolvedClass: // fall through
273 {
274 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
275 THREAD);
277 if (scratch_i != *merge_cp_length_p) {
278 // The new entry in *merge_cp_p is at a different index than
279 // the new entry in scratch_cp so we need to map the index values.
280 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
281 }
282 (*merge_cp_length_p)++;
283 } break;
285 // this is an indirect CP entry so it needs special handling
286 case JVM_CONSTANT_NameAndType:
287 {
288 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
289 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
290 merge_cp_length_p, THREAD);
292 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
293 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
294 merge_cp_p, merge_cp_length_p,
295 THREAD);
297 // If the referenced entries already exist in *merge_cp_p, then
298 // both new_name_ref_i and new_signature_ref_i will both be 0.
299 // In that case, all we are appending is the current entry.
300 if (new_name_ref_i != name_ref_i) {
301 RC_TRACE(0x00080000,
302 ("NameAndType entry@%d name_ref_index change: %d to %d",
303 *merge_cp_length_p, name_ref_i, new_name_ref_i));
304 }
305 if (new_signature_ref_i != signature_ref_i) {
306 RC_TRACE(0x00080000,
307 ("NameAndType entry@%d signature_ref_index change: %d to %d",
308 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
309 }
311 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
312 new_name_ref_i, new_signature_ref_i);
313 if (scratch_i != *merge_cp_length_p) {
314 // The new entry in *merge_cp_p is at a different index than
315 // the new entry in scratch_cp so we need to map the index values.
316 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
317 }
318 (*merge_cp_length_p)++;
319 } break;
321 // this is a double-indirect CP entry so it needs special handling
322 case JVM_CONSTANT_Fieldref: // fall through
323 case JVM_CONSTANT_InterfaceMethodref: // fall through
324 case JVM_CONSTANT_Methodref:
325 {
326 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
327 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
328 merge_cp_p, merge_cp_length_p, THREAD);
330 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
331 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
332 merge_cp_p, merge_cp_length_p, THREAD);
334 const char *entry_name;
335 switch (scratch_cp->tag_at(scratch_i).value()) {
336 case JVM_CONSTANT_Fieldref:
337 entry_name = "Fieldref";
338 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
339 new_name_and_type_ref_i);
340 break;
341 case JVM_CONSTANT_InterfaceMethodref:
342 entry_name = "IFMethodref";
343 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
344 new_klass_ref_i, new_name_and_type_ref_i);
345 break;
346 case JVM_CONSTANT_Methodref:
347 entry_name = "Methodref";
348 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
349 new_name_and_type_ref_i);
350 break;
351 default:
352 guarantee(false, "bad switch");
353 break;
354 }
356 if (klass_ref_i != new_klass_ref_i) {
357 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
358 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
359 }
360 if (name_and_type_ref_i != new_name_and_type_ref_i) {
361 RC_TRACE(0x00080000,
362 ("%s entry@%d name_and_type_index changed: %d to %d",
363 entry_name, *merge_cp_length_p, name_and_type_ref_i,
364 new_name_and_type_ref_i));
365 }
367 if (scratch_i != *merge_cp_length_p) {
368 // The new entry in *merge_cp_p is at a different index than
369 // the new entry in scratch_cp so we need to map the index values.
370 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
371 }
372 (*merge_cp_length_p)++;
373 } break;
375 // this is an indirect CP entry so it needs special handling
376 case JVM_CONSTANT_MethodType:
377 {
378 int ref_i = scratch_cp->method_type_index_at(scratch_i);
379 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
380 merge_cp_length_p, THREAD);
381 if (new_ref_i != ref_i) {
382 RC_TRACE(0x00080000,
383 ("MethodType entry@%d ref_index change: %d to %d",
384 *merge_cp_length_p, ref_i, new_ref_i));
385 }
386 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
387 if (scratch_i != *merge_cp_length_p) {
388 // The new entry in *merge_cp_p is at a different index than
389 // the new entry in scratch_cp so we need to map the index values.
390 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
391 }
392 (*merge_cp_length_p)++;
393 } break;
395 // this is an indirect CP entry so it needs special handling
396 case JVM_CONSTANT_MethodHandle:
397 {
398 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
399 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
400 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
401 merge_cp_length_p, THREAD);
402 if (new_ref_i != ref_i) {
403 RC_TRACE(0x00080000,
404 ("MethodHandle entry@%d ref_index change: %d to %d",
405 *merge_cp_length_p, ref_i, new_ref_i));
406 }
407 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
408 if (scratch_i != *merge_cp_length_p) {
409 // The new entry in *merge_cp_p is at a different index than
410 // the new entry in scratch_cp so we need to map the index values.
411 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
412 }
413 (*merge_cp_length_p)++;
414 } break;
416 // this is an indirect CP entry so it needs special handling
417 case JVM_CONSTANT_InvokeDynamic:
418 {
419 // Index of the bootstrap specifier in the operands array
420 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
421 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
422 merge_cp_length_p, THREAD);
423 // The bootstrap method NameAndType_info index
424 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
425 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
426 merge_cp_length_p, THREAD);
427 if (new_bs_i != old_bs_i) {
428 RC_TRACE(0x00080000,
429 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
430 *merge_cp_length_p, old_bs_i, new_bs_i));
431 }
432 if (new_ref_i != old_ref_i) {
433 RC_TRACE(0x00080000,
434 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
435 *merge_cp_length_p, old_ref_i, new_ref_i));
436 }
438 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
439 if (scratch_i != *merge_cp_length_p) {
440 // The new entry in *merge_cp_p is at a different index than
441 // the new entry in scratch_cp so we need to map the index values.
442 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
443 }
444 (*merge_cp_length_p)++;
445 } break;
447 // At this stage, Class or UnresolvedClass could be here, but not
448 // ClassIndex
449 case JVM_CONSTANT_ClassIndex: // fall through
451 // Invalid is used as the tag for the second constant pool entry
452 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
453 // not be seen by itself.
454 case JVM_CONSTANT_Invalid: // fall through
456 // At this stage, String could be here, but not StringIndex
457 case JVM_CONSTANT_StringIndex: // fall through
459 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
460 // here
461 case JVM_CONSTANT_UnresolvedClassInError: // fall through
463 default:
464 {
465 // leave a breadcrumb
466 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
467 ShouldNotReachHere();
468 } break;
469 } // end switch tag value
470 } // end append_entry()
473 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
474 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
476 int new_ref_i = ref_i;
477 bool match = (ref_i < *merge_cp_length_p) &&
478 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
480 if (!match) {
481 // forward reference in *merge_cp_p or not a direct match
482 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
483 if (found_i != 0) {
484 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
485 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
486 new_ref_i = found_i;
487 map_index(scratch_cp, ref_i, found_i);
488 } else {
489 // no match found so we have to append this entry to *merge_cp_p
490 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
491 // The above call to append_entry() can only append one entry
492 // so the post call query of *merge_cp_length_p is only for
493 // the sake of consistency.
494 new_ref_i = *merge_cp_length_p - 1;
495 }
496 }
498 return new_ref_i;
499 } // end find_or_append_indirect_entry()
502 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
503 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
504 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
505 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
506 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
508 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
509 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
510 merge_cp_length_p, THREAD);
511 if (new_ref_i != old_ref_i) {
512 RC_TRACE(0x00080000,
513 ("operands entry@%d bootstrap method ref_index change: %d to %d",
514 _operands_cur_length, old_ref_i, new_ref_i));
515 }
517 Array<u2>* merge_ops = (*merge_cp_p)->operands();
518 int new_bs_i = _operands_cur_length;
519 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
520 // However, the operand_offset_at(0) was set in the extend_operands() call.
521 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
522 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
523 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
525 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
526 merge_ops->at_put(new_base++, new_ref_i);
527 merge_ops->at_put(new_base++, argc);
529 for (int i = 0; i < argc; i++) {
530 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
531 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
532 merge_cp_length_p, THREAD);
533 merge_ops->at_put(new_base++, new_arg_ref_i);
534 if (new_arg_ref_i != old_arg_ref_i) {
535 RC_TRACE(0x00080000,
536 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
537 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
538 }
539 }
540 if (old_bs_i != _operands_cur_length) {
541 // The bootstrap specifier in *merge_cp_p is at a different index than
542 // that in scratch_cp so we need to map the index values.
543 map_operand_index(old_bs_i, new_bs_i);
544 }
545 _operands_cur_length++;
546 } // end append_operand()
549 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
550 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
552 int new_bs_i = old_bs_i; // bootstrap specifier index
553 bool match = (old_bs_i < _operands_cur_length) &&
554 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
556 if (!match) {
557 // forward reference in *merge_cp_p or not a direct match
558 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
559 _operands_cur_length, THREAD);
560 if (found_i != -1) {
561 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
562 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
563 new_bs_i = found_i;
564 map_operand_index(old_bs_i, found_i);
565 } else {
566 // no match found so we have to append this bootstrap specifier to *merge_cp_p
567 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
568 new_bs_i = _operands_cur_length - 1;
569 }
570 }
571 return new_bs_i;
572 } // end find_or_append_operand()
575 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
576 if (merge_cp->operands() == NULL) {
577 return;
578 }
579 // Shrink the merge_cp operands
580 merge_cp->shrink_operands(_operands_cur_length, CHECK);
582 if (RC_TRACE_ENABLED(0x00040000)) {
583 // don't want to loop unless we are tracing
584 int count = 0;
585 for (int i = 1; i < _operands_index_map_p->length(); i++) {
586 int value = _operands_index_map_p->at(i);
587 if (value != -1) {
588 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
589 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
590 count++;
591 }
592 }
593 }
594 // Clean-up
595 _operands_index_map_p = NULL;
596 _operands_cur_length = 0;
597 _operands_index_map_count = 0;
598 } // end finalize_operands_merge()
601 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
602 instanceKlassHandle the_class,
603 instanceKlassHandle scratch_class) {
604 int i;
606 // Check superclasses, or rather their names, since superclasses themselves can be
607 // requested to replace.
608 // Check for NULL superclass first since this might be java.lang.Object
609 if (the_class->super() != scratch_class->super() &&
610 (the_class->super() == NULL || scratch_class->super() == NULL ||
611 the_class->super()->name() !=
612 scratch_class->super()->name())) {
613 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
614 }
616 // Check if the number, names and order of directly implemented interfaces are the same.
617 // I think in principle we should just check if the sets of names of directly implemented
618 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
619 // .java file, also changes in .class file) should not matter. However, comparing sets is
620 // technically a bit more difficult, and, more importantly, I am not sure at present that the
621 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
622 // rely on it somewhere.
623 Array<Klass*>* k_interfaces = the_class->local_interfaces();
624 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
625 int n_intfs = k_interfaces->length();
626 if (n_intfs != k_new_interfaces->length()) {
627 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
628 }
629 for (i = 0; i < n_intfs; i++) {
630 if (k_interfaces->at(i)->name() !=
631 k_new_interfaces->at(i)->name()) {
632 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
633 }
634 }
636 // Check whether class is in the error init state.
637 if (the_class->is_in_error_state()) {
638 // TBD #5057930: special error code is needed in 1.6
639 return JVMTI_ERROR_INVALID_CLASS;
640 }
642 // Check whether class modifiers are the same.
643 jushort old_flags = (jushort) the_class->access_flags().get_flags();
644 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
645 if (old_flags != new_flags) {
646 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
647 }
649 // Check if the number, names, types and order of fields declared in these classes
650 // are the same.
651 JavaFieldStream old_fs(the_class);
652 JavaFieldStream new_fs(scratch_class);
653 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
654 // access
655 old_flags = old_fs.access_flags().as_short();
656 new_flags = new_fs.access_flags().as_short();
657 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
658 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
659 }
660 // offset
661 if (old_fs.offset() != new_fs.offset()) {
662 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
663 }
664 // name and signature
665 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
666 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
667 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
668 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
669 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
670 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
671 }
672 }
674 // If both streams aren't done then we have a differing number of
675 // fields.
676 if (!old_fs.done() || !new_fs.done()) {
677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
678 }
680 // Do a parallel walk through the old and new methods. Detect
681 // cases where they match (exist in both), have been added in
682 // the new methods, or have been deleted (exist only in the
683 // old methods). The class file parser places methods in order
684 // by method name, but does not order overloaded methods by
685 // signature. In order to determine what fate befell the methods,
686 // this code places the overloaded new methods that have matching
687 // old methods in the same order as the old methods and places
688 // new overloaded methods at the end of overloaded methods of
689 // that name. The code for this order normalization is adapted
690 // from the algorithm used in InstanceKlass::find_method().
691 // Since we are swapping out of order entries as we find them,
692 // we only have to search forward through the overloaded methods.
693 // Methods which are added and have the same name as an existing
694 // method (but different signature) will be put at the end of
695 // the methods with that name, and the name mismatch code will
696 // handle them.
697 Array<Method*>* k_old_methods(the_class->methods());
698 Array<Method*>* k_new_methods(scratch_class->methods());
699 int n_old_methods = k_old_methods->length();
700 int n_new_methods = k_new_methods->length();
701 Thread* thread = Thread::current();
703 int ni = 0;
704 int oi = 0;
705 while (true) {
706 Method* k_old_method;
707 Method* k_new_method;
708 enum { matched, added, deleted, undetermined } method_was = undetermined;
710 if (oi >= n_old_methods) {
711 if (ni >= n_new_methods) {
712 break; // we've looked at everything, done
713 }
714 // New method at the end
715 k_new_method = k_new_methods->at(ni);
716 method_was = added;
717 } else if (ni >= n_new_methods) {
718 // Old method, at the end, is deleted
719 k_old_method = k_old_methods->at(oi);
720 method_was = deleted;
721 } else {
722 // There are more methods in both the old and new lists
723 k_old_method = k_old_methods->at(oi);
724 k_new_method = k_new_methods->at(ni);
725 if (k_old_method->name() != k_new_method->name()) {
726 // Methods are sorted by method name, so a mismatch means added
727 // or deleted
728 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
729 method_was = added;
730 } else {
731 method_was = deleted;
732 }
733 } else if (k_old_method->signature() == k_new_method->signature()) {
734 // Both the name and signature match
735 method_was = matched;
736 } else {
737 // The name matches, but the signature doesn't, which means we have to
738 // search forward through the new overloaded methods.
739 int nj; // outside the loop for post-loop check
740 for (nj = ni + 1; nj < n_new_methods; nj++) {
741 Method* m = k_new_methods->at(nj);
742 if (k_old_method->name() != m->name()) {
743 // reached another method name so no more overloaded methods
744 method_was = deleted;
745 break;
746 }
747 if (k_old_method->signature() == m->signature()) {
748 // found a match so swap the methods
749 k_new_methods->at_put(ni, m);
750 k_new_methods->at_put(nj, k_new_method);
751 k_new_method = m;
752 method_was = matched;
753 break;
754 }
755 }
757 if (nj >= n_new_methods) {
758 // reached the end without a match; so method was deleted
759 method_was = deleted;
760 }
761 }
762 }
764 switch (method_was) {
765 case matched:
766 // methods match, be sure modifiers do too
767 old_flags = (jushort) k_old_method->access_flags().get_flags();
768 new_flags = (jushort) k_new_method->access_flags().get_flags();
769 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
770 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
771 }
772 {
773 u2 new_num = k_new_method->method_idnum();
774 u2 old_num = k_old_method->method_idnum();
775 if (new_num != old_num) {
776 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
777 if (idnum_owner != NULL) {
778 // There is already a method assigned this idnum -- switch them
779 idnum_owner->set_method_idnum(new_num);
780 }
781 k_new_method->set_method_idnum(old_num);
782 if (thread->has_pending_exception()) {
783 return JVMTI_ERROR_OUT_OF_MEMORY;
784 }
785 }
786 }
787 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
788 k_new_method->name_and_sig_as_C_string(), ni,
789 k_old_method->name_and_sig_as_C_string(), oi));
790 // advance to next pair of methods
791 ++oi;
792 ++ni;
793 break;
794 case added:
795 // method added, see if it is OK
796 new_flags = (jushort) k_new_method->access_flags().get_flags();
797 if ((new_flags & JVM_ACC_PRIVATE) == 0
798 // hack: private should be treated as final, but alas
799 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
800 ) {
801 // new methods must be private
802 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
803 }
804 {
805 u2 num = the_class->next_method_idnum();
806 if (num == ConstMethod::UNSET_IDNUM) {
807 // cannot add any more methods
808 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
809 }
810 u2 new_num = k_new_method->method_idnum();
811 Method* idnum_owner = scratch_class->method_with_idnum(num);
812 if (idnum_owner != NULL) {
813 // There is already a method assigned this idnum -- switch them
814 idnum_owner->set_method_idnum(new_num);
815 }
816 k_new_method->set_method_idnum(num);
817 if (thread->has_pending_exception()) {
818 return JVMTI_ERROR_OUT_OF_MEMORY;
819 }
820 }
821 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
822 k_new_method->name_and_sig_as_C_string(), ni));
823 ++ni; // advance to next new method
824 break;
825 case deleted:
826 // method deleted, see if it is OK
827 old_flags = (jushort) k_old_method->access_flags().get_flags();
828 if ((old_flags & JVM_ACC_PRIVATE) == 0
829 // hack: private should be treated as final, but alas
830 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
831 ) {
832 // deleted methods must be private
833 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
834 }
835 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
836 k_old_method->name_and_sig_as_C_string(), oi));
837 ++oi; // advance to next old method
838 break;
839 default:
840 ShouldNotReachHere();
841 }
842 }
844 return JVMTI_ERROR_NONE;
845 }
848 // Find new constant pool index value for old constant pool index value
849 // by seaching the index map. Returns zero (0) if there is no mapped
850 // value for the old constant pool index.
851 int VM_RedefineClasses::find_new_index(int old_index) {
852 if (_index_map_count == 0) {
853 // map is empty so nothing can be found
854 return 0;
855 }
857 if (old_index < 1 || old_index >= _index_map_p->length()) {
858 // The old_index is out of range so it is not mapped. This should
859 // not happen in regular constant pool merging use, but it can
860 // happen if a corrupt annotation is processed.
861 return 0;
862 }
864 int value = _index_map_p->at(old_index);
865 if (value == -1) {
866 // the old_index is not mapped
867 return 0;
868 }
870 return value;
871 } // end find_new_index()
874 // Find new bootstrap specifier index value for old bootstrap specifier index
875 // value by seaching the index map. Returns unused index (-1) if there is
876 // no mapped value for the old bootstrap specifier index.
877 int VM_RedefineClasses::find_new_operand_index(int old_index) {
878 if (_operands_index_map_count == 0) {
879 // map is empty so nothing can be found
880 return -1;
881 }
883 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
884 // The old_index is out of range so it is not mapped.
885 // This should not happen in regular constant pool merging use.
886 return -1;
887 }
889 int value = _operands_index_map_p->at(old_index);
890 if (value == -1) {
891 // the old_index is not mapped
892 return -1;
893 }
895 return value;
896 } // end find_new_operand_index()
899 // Returns true if the current mismatch is due to a resolved/unresolved
900 // class pair. Otherwise, returns false.
901 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
902 int index1, constantPoolHandle cp2, int index2) {
904 jbyte t1 = cp1->tag_at(index1).value();
905 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
906 return false; // wrong entry type; not our special case
907 }
909 jbyte t2 = cp2->tag_at(index2).value();
910 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
911 return false; // wrong entry type; not our special case
912 }
914 if (t1 == t2) {
915 return false; // not a mismatch; not our special case
916 }
918 char *s1 = cp1->klass_name_at(index1)->as_C_string();
919 char *s2 = cp2->klass_name_at(index2)->as_C_string();
920 if (strcmp(s1, s2) != 0) {
921 return false; // strings don't match; not our special case
922 }
924 return true; // made it through the gauntlet; this is our special case
925 } // end is_unresolved_class_mismatch()
928 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
930 // For consistency allocate memory using os::malloc wrapper.
931 _scratch_classes = (Klass**)
932 os::malloc(sizeof(Klass*) * _class_count, mtClass);
933 if (_scratch_classes == NULL) {
934 return JVMTI_ERROR_OUT_OF_MEMORY;
935 }
936 // Zero initialize the _scratch_classes array.
937 for (int i = 0; i < _class_count; i++) {
938 _scratch_classes[i] = NULL;
939 }
941 ResourceMark rm(THREAD);
943 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
944 // state can only be NULL if the current thread is exiting which
945 // should not happen since we're trying to do a RedefineClasses
946 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
947 for (int i = 0; i < _class_count; i++) {
948 // Create HandleMark so that any handles created while loading new class
949 // versions are deleted. Constant pools are deallocated while merging
950 // constant pools
951 HandleMark hm(THREAD);
953 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
954 // classes for primitives cannot be redefined
955 if (!is_modifiable_class(mirror)) {
956 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
957 }
958 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
959 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
960 Symbol* the_class_sym = the_class->name();
962 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
963 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
964 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
965 the_class->external_name(), _class_load_kind,
966 os::available_memory() >> 10));
968 ClassFileStream st((u1*) _class_defs[i].class_bytes,
969 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
971 // Parse the stream.
972 Handle the_class_loader(THREAD, the_class->class_loader());
973 Handle protection_domain(THREAD, the_class->protection_domain());
974 // Set redefined class handle in JvmtiThreadState class.
975 // This redefined class is sent to agent event handler for class file
976 // load hook event.
977 state->set_class_being_redefined(&the_class, _class_load_kind);
979 Klass* k = SystemDictionary::parse_stream(the_class_sym,
980 the_class_loader,
981 protection_domain,
982 &st,
983 THREAD);
984 // Clear class_being_redefined just to be sure.
985 state->clear_class_being_redefined();
987 // TODO: if this is retransform, and nothing changed we can skip it
989 instanceKlassHandle scratch_class (THREAD, k);
991 // Need to clean up allocated InstanceKlass if there's an error so assign
992 // the result here. Caller deallocates all the scratch classes in case of
993 // an error.
994 _scratch_classes[i] = k;
996 if (HAS_PENDING_EXCEPTION) {
997 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
998 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
999 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1000 ex_name->as_C_string()));
1001 CLEAR_PENDING_EXCEPTION;
1003 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1004 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1005 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1006 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1007 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1008 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1009 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1010 // The message will be "XXX (wrong name: YYY)"
1011 return JVMTI_ERROR_NAMES_DONT_MATCH;
1012 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1013 return JVMTI_ERROR_OUT_OF_MEMORY;
1014 } else { // Just in case more exceptions can be thrown..
1015 return JVMTI_ERROR_FAILS_VERIFICATION;
1016 }
1017 }
1019 // Ensure class is linked before redefine
1020 if (!the_class->is_linked()) {
1021 the_class->link_class(THREAD);
1022 if (HAS_PENDING_EXCEPTION) {
1023 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1024 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1025 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1026 ex_name->as_C_string()));
1027 CLEAR_PENDING_EXCEPTION;
1028 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1029 return JVMTI_ERROR_OUT_OF_MEMORY;
1030 } else {
1031 return JVMTI_ERROR_INTERNAL;
1032 }
1033 }
1034 }
1036 // Do the validity checks in compare_and_normalize_class_versions()
1037 // before verifying the byte codes. By doing these checks first, we
1038 // limit the number of functions that require redirection from
1039 // the_class to scratch_class. In particular, we don't have to
1040 // modify JNI GetSuperclass() and thus won't change its performance.
1041 jvmtiError res = compare_and_normalize_class_versions(the_class,
1042 scratch_class);
1043 if (res != JVMTI_ERROR_NONE) {
1044 return res;
1045 }
1047 // verify what the caller passed us
1048 {
1049 // The bug 6214132 caused the verification to fail.
1050 // Information about the_class and scratch_class is temporarily
1051 // recorded into jvmtiThreadState. This data is used to redirect
1052 // the_class to scratch_class in the JVM_* functions called by the
1053 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1054 // description.
1055 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1056 Verifier::verify(
1057 scratch_class, Verifier::ThrowException, true, THREAD);
1058 }
1060 if (HAS_PENDING_EXCEPTION) {
1061 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1062 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1063 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1064 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1065 CLEAR_PENDING_EXCEPTION;
1066 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1067 return JVMTI_ERROR_OUT_OF_MEMORY;
1068 } else {
1069 // tell the caller the bytecodes are bad
1070 return JVMTI_ERROR_FAILS_VERIFICATION;
1071 }
1072 }
1074 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1075 if (res != JVMTI_ERROR_NONE) {
1076 return res;
1077 }
1079 if (VerifyMergedCPBytecodes) {
1080 // verify what we have done during constant pool merging
1081 {
1082 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1083 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1084 }
1086 if (HAS_PENDING_EXCEPTION) {
1087 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1088 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1089 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1090 ("verify_byte_codes post merge-CP exception: '%s'",
1091 ex_name->as_C_string()));
1092 CLEAR_PENDING_EXCEPTION;
1093 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1094 return JVMTI_ERROR_OUT_OF_MEMORY;
1095 } else {
1096 // tell the caller that constant pool merging screwed up
1097 return JVMTI_ERROR_INTERNAL;
1098 }
1099 }
1100 }
1102 Rewriter::rewrite(scratch_class, THREAD);
1103 if (!HAS_PENDING_EXCEPTION) {
1104 scratch_class->link_methods(THREAD);
1105 }
1106 if (HAS_PENDING_EXCEPTION) {
1107 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1108 CLEAR_PENDING_EXCEPTION;
1109 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1110 return JVMTI_ERROR_OUT_OF_MEMORY;
1111 } else {
1112 return JVMTI_ERROR_INTERNAL;
1113 }
1114 }
1116 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1117 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1118 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1119 the_class->external_name(), os::available_memory() >> 10));
1120 }
1122 return JVMTI_ERROR_NONE;
1123 }
1126 // Map old_index to new_index as needed. scratch_cp is only needed
1127 // for RC_TRACE() calls.
1128 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1129 int old_index, int new_index) {
1130 if (find_new_index(old_index) != 0) {
1131 // old_index is already mapped
1132 return;
1133 }
1135 if (old_index == new_index) {
1136 // no mapping is needed
1137 return;
1138 }
1140 _index_map_p->at_put(old_index, new_index);
1141 _index_map_count++;
1143 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1144 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1145 } // end map_index()
1148 // Map old_index to new_index as needed.
1149 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1150 if (find_new_operand_index(old_index) != -1) {
1151 // old_index is already mapped
1152 return;
1153 }
1155 if (old_index == new_index) {
1156 // no mapping is needed
1157 return;
1158 }
1160 _operands_index_map_p->at_put(old_index, new_index);
1161 _operands_index_map_count++;
1163 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1164 } // end map_index()
1167 // Merge old_cp and scratch_cp and return the results of the merge via
1168 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1169 // merge_cp_length_p. The entries in old_cp occupy the same locations
1170 // in *merge_cp_p. Also creates a map of indices from entries in
1171 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1172 // entries are only created for entries in scratch_cp that occupy a
1173 // different location in *merged_cp_p.
1174 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1175 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1176 int *merge_cp_length_p, TRAPS) {
1178 if (merge_cp_p == NULL) {
1179 assert(false, "caller must provide scratch constantPool");
1180 return false; // robustness
1181 }
1182 if (merge_cp_length_p == NULL) {
1183 assert(false, "caller must provide scratch CP length");
1184 return false; // robustness
1185 }
1186 // Worst case we need old_cp->length() + scratch_cp()->length(),
1187 // but the caller might be smart so make sure we have at least
1188 // the minimum.
1189 if ((*merge_cp_p)->length() < old_cp->length()) {
1190 assert(false, "merge area too small");
1191 return false; // robustness
1192 }
1194 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1195 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1196 scratch_cp->length()));
1198 {
1199 // Pass 0:
1200 // The old_cp is copied to *merge_cp_p; this means that any code
1201 // using old_cp does not have to change. This work looks like a
1202 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1203 // handle one special case:
1204 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1205 // This will make verification happy.
1207 int old_i; // index into old_cp
1209 // index zero (0) is not used in constantPools
1210 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1211 // leave debugging crumb
1212 jbyte old_tag = old_cp->tag_at(old_i).value();
1213 switch (old_tag) {
1214 case JVM_CONSTANT_Class:
1215 case JVM_CONSTANT_UnresolvedClass:
1216 // revert the copy to JVM_CONSTANT_UnresolvedClass
1217 // May be resolving while calling this so do the same for
1218 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1219 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1220 old_cp->klass_name_at(old_i));
1221 break;
1223 case JVM_CONSTANT_Double:
1224 case JVM_CONSTANT_Long:
1225 // just copy the entry to *merge_cp_p, but double and long take
1226 // two constant pool entries
1227 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1228 old_i++;
1229 break;
1231 default:
1232 // just copy the entry to *merge_cp_p
1233 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1234 break;
1235 }
1236 } // end for each old_cp entry
1238 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1239 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1241 // We don't need to sanity check that *merge_cp_length_p is within
1242 // *merge_cp_p bounds since we have the minimum on-entry check above.
1243 (*merge_cp_length_p) = old_i;
1244 }
1246 // merge_cp_len should be the same as old_cp->length() at this point
1247 // so this trace message is really a "warm-and-breathing" message.
1248 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1249 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1251 int scratch_i; // index into scratch_cp
1252 {
1253 // Pass 1a:
1254 // Compare scratch_cp entries to the old_cp entries that we have
1255 // already copied to *merge_cp_p. In this pass, we are eliminating
1256 // exact duplicates (matching entry at same index) so we only
1257 // compare entries in the common indice range.
1258 int increment = 1;
1259 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1260 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1261 switch (scratch_cp->tag_at(scratch_i).value()) {
1262 case JVM_CONSTANT_Double:
1263 case JVM_CONSTANT_Long:
1264 // double and long take two constant pool entries
1265 increment = 2;
1266 break;
1268 default:
1269 increment = 1;
1270 break;
1271 }
1273 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1274 scratch_i, CHECK_0);
1275 if (match) {
1276 // found a match at the same index so nothing more to do
1277 continue;
1278 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1279 *merge_cp_p, scratch_i)) {
1280 // The mismatch in compare_entry_to() above is because of a
1281 // resolved versus unresolved class entry at the same index
1282 // with the same string value. Since Pass 0 reverted any
1283 // class entries to unresolved class entries in *merge_cp_p,
1284 // we go with the unresolved class entry.
1285 continue;
1286 }
1288 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1289 CHECK_0);
1290 if (found_i != 0) {
1291 guarantee(found_i != scratch_i,
1292 "compare_entry_to() and find_matching_entry() do not agree");
1294 // Found a matching entry somewhere else in *merge_cp_p so
1295 // just need a mapping entry.
1296 map_index(scratch_cp, scratch_i, found_i);
1297 continue;
1298 }
1300 // The find_matching_entry() call above could fail to find a match
1301 // due to a resolved versus unresolved class or string entry situation
1302 // like we solved above with the is_unresolved_*_mismatch() calls.
1303 // However, we would have to call is_unresolved_*_mismatch() over
1304 // all of *merge_cp_p (potentially) and that doesn't seem to be
1305 // worth the time.
1307 // No match found so we have to append this entry and any unique
1308 // referenced entries to *merge_cp_p.
1309 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1310 CHECK_0);
1311 }
1312 }
1314 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1315 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1316 *merge_cp_length_p, scratch_i, _index_map_count));
1318 if (scratch_i < scratch_cp->length()) {
1319 // Pass 1b:
1320 // old_cp is smaller than scratch_cp so there are entries in
1321 // scratch_cp that we have not yet processed. We take care of
1322 // those now.
1323 int increment = 1;
1324 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1325 switch (scratch_cp->tag_at(scratch_i).value()) {
1326 case JVM_CONSTANT_Double:
1327 case JVM_CONSTANT_Long:
1328 // double and long take two constant pool entries
1329 increment = 2;
1330 break;
1332 default:
1333 increment = 1;
1334 break;
1335 }
1337 int found_i =
1338 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1339 if (found_i != 0) {
1340 // Found a matching entry somewhere else in *merge_cp_p so
1341 // just need a mapping entry.
1342 map_index(scratch_cp, scratch_i, found_i);
1343 continue;
1344 }
1346 // No match found so we have to append this entry and any unique
1347 // referenced entries to *merge_cp_p.
1348 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1349 CHECK_0);
1350 }
1352 finalize_operands_merge(*merge_cp_p, THREAD);
1354 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1355 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1356 *merge_cp_length_p, scratch_i, _index_map_count));
1357 }
1359 return true;
1360 } // end merge_constant_pools()
1363 // Scoped object to clean up the constant pool(s) created for merging
1364 class MergeCPCleaner {
1365 ClassLoaderData* _loader_data;
1366 ConstantPool* _cp;
1367 ConstantPool* _scratch_cp;
1368 public:
1369 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1370 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1371 ~MergeCPCleaner() {
1372 _loader_data->add_to_deallocate_list(_cp);
1373 if (_scratch_cp != NULL) {
1374 _loader_data->add_to_deallocate_list(_scratch_cp);
1375 }
1376 }
1377 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1378 };
1380 // Merge constant pools between the_class and scratch_class and
1381 // potentially rewrite bytecodes in scratch_class to use the merged
1382 // constant pool.
1383 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1384 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1385 TRAPS) {
1386 // worst case merged constant pool length is old and new combined
1387 int merge_cp_length = the_class->constants()->length()
1388 + scratch_class->constants()->length();
1390 // Constant pools are not easily reused so we allocate a new one
1391 // each time.
1392 // merge_cp is created unsafe for concurrent GC processing. It
1393 // should be marked safe before discarding it. Even though
1394 // garbage, if it crosses a card boundary, it may be scanned
1395 // in order to find the start of the first complete object on the card.
1396 ClassLoaderData* loader_data = the_class->class_loader_data();
1397 ConstantPool* merge_cp_oop =
1398 ConstantPool::allocate(loader_data,
1399 merge_cp_length,
1400 THREAD);
1401 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1403 HandleMark hm(THREAD); // make sure handles are cleared before
1404 // MergeCPCleaner clears out merge_cp_oop
1405 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1407 // Get constants() from the old class because it could have been rewritten
1408 // while we were at a safepoint allocating a new constant pool.
1409 constantPoolHandle old_cp(THREAD, the_class->constants());
1410 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1412 // If the length changed, the class was redefined out from under us. Return
1413 // an error.
1414 if (merge_cp_length != the_class->constants()->length()
1415 + scratch_class->constants()->length()) {
1416 return JVMTI_ERROR_INTERNAL;
1417 }
1419 // Update the version number of the constant pool
1420 merge_cp->increment_and_save_version(old_cp->version());
1422 ResourceMark rm(THREAD);
1423 _index_map_count = 0;
1424 _index_map_p = new intArray(scratch_cp->length(), -1);
1426 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1427 _operands_index_map_count = 0;
1428 _operands_index_map_p = new intArray(
1429 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1431 // reference to the cp holder is needed for copy_operands()
1432 merge_cp->set_pool_holder(scratch_class());
1433 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1434 &merge_cp_length, THREAD);
1435 merge_cp->set_pool_holder(NULL);
1437 if (!result) {
1438 // The merge can fail due to memory allocation failure or due
1439 // to robustness checks.
1440 return JVMTI_ERROR_INTERNAL;
1441 }
1443 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1444 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1446 if (_index_map_count == 0) {
1447 // there is nothing to map between the new and merged constant pools
1449 if (old_cp->length() == scratch_cp->length()) {
1450 // The old and new constant pools are the same length and the
1451 // index map is empty. This means that the three constant pools
1452 // are equivalent (but not the same). Unfortunately, the new
1453 // constant pool has not gone through link resolution nor have
1454 // the new class bytecodes gone through constant pool cache
1455 // rewriting so we can't use the old constant pool with the new
1456 // class.
1458 // toss the merged constant pool at return
1459 } else if (old_cp->length() < scratch_cp->length()) {
1460 // The old constant pool has fewer entries than the new constant
1461 // pool and the index map is empty. This means the new constant
1462 // pool is a superset of the old constant pool. However, the old
1463 // class bytecodes have already gone through constant pool cache
1464 // rewriting so we can't use the new constant pool with the old
1465 // class.
1467 // toss the merged constant pool at return
1468 } else {
1469 // The old constant pool has more entries than the new constant
1470 // pool and the index map is empty. This means that both the old
1471 // and merged constant pools are supersets of the new constant
1472 // pool.
1474 // Replace the new constant pool with a shrunken copy of the
1475 // merged constant pool
1476 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1477 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1478 // It can't be cleaned up while there are handles to it.
1479 cp_cleaner.add_scratch_cp(scratch_cp());
1480 }
1481 } else {
1482 if (RC_TRACE_ENABLED(0x00040000)) {
1483 // don't want to loop unless we are tracing
1484 int count = 0;
1485 for (int i = 1; i < _index_map_p->length(); i++) {
1486 int value = _index_map_p->at(i);
1488 if (value != -1) {
1489 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1490 ("index_map[%d]: old=%d new=%d", count, i, value));
1491 count++;
1492 }
1493 }
1494 }
1496 // We have entries mapped between the new and merged constant pools
1497 // so we have to rewrite some constant pool references.
1498 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1499 return JVMTI_ERROR_INTERNAL;
1500 }
1502 // Replace the new constant pool with a shrunken copy of the
1503 // merged constant pool so now the rewritten bytecodes have
1504 // valid references; the previous new constant pool will get
1505 // GCed.
1506 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1507 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1508 // It can't be cleaned up while there are handles to it.
1509 cp_cleaner.add_scratch_cp(scratch_cp());
1510 }
1512 return JVMTI_ERROR_NONE;
1513 } // end merge_cp_and_rewrite()
1516 // Rewrite constant pool references in klass scratch_class.
1517 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1518 TRAPS) {
1520 // rewrite constant pool references in the methods:
1521 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1522 // propagate failure back to caller
1523 return false;
1524 }
1526 // rewrite constant pool references in the class_annotations:
1527 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1528 // propagate failure back to caller
1529 return false;
1530 }
1532 // rewrite constant pool references in the fields_annotations:
1533 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1534 // propagate failure back to caller
1535 return false;
1536 }
1538 // rewrite constant pool references in the methods_annotations:
1539 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1540 // propagate failure back to caller
1541 return false;
1542 }
1544 // rewrite constant pool references in the methods_parameter_annotations:
1545 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1546 THREAD)) {
1547 // propagate failure back to caller
1548 return false;
1549 }
1551 // rewrite constant pool references in the methods_default_annotations:
1552 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1553 THREAD)) {
1554 // propagate failure back to caller
1555 return false;
1556 }
1558 return true;
1559 } // end rewrite_cp_refs()
1561 // Rewrite constant pool references in the methods.
1562 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1563 instanceKlassHandle scratch_class, TRAPS) {
1565 Array<Method*>* methods = scratch_class->methods();
1567 if (methods == NULL || methods->length() == 0) {
1568 // no methods so nothing to do
1569 return true;
1570 }
1572 // rewrite constant pool references in the methods:
1573 for (int i = methods->length() - 1; i >= 0; i--) {
1574 methodHandle method(THREAD, methods->at(i));
1575 methodHandle new_method;
1576 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1577 if (!new_method.is_null()) {
1578 // the method has been replaced so save the new method version
1579 methods->at_put(i, new_method());
1580 }
1581 }
1583 return true;
1584 }
1587 // Rewrite constant pool references in the specific method. This code
1588 // was adapted from Rewriter::rewrite_method().
1589 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1590 methodHandle *new_method_p, TRAPS) {
1592 *new_method_p = methodHandle(); // default is no new method
1594 // We cache a pointer to the bytecodes here in code_base. If GC
1595 // moves the Method*, then the bytecodes will also move which
1596 // will likely cause a crash. We create a No_Safepoint_Verifier
1597 // object to detect whether we pass a possible safepoint in this
1598 // code block.
1599 No_Safepoint_Verifier nsv;
1601 // Bytecodes and their length
1602 address code_base = method->code_base();
1603 int code_length = method->code_size();
1605 int bc_length;
1606 for (int bci = 0; bci < code_length; bci += bc_length) {
1607 address bcp = code_base + bci;
1608 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1610 bc_length = Bytecodes::length_for(c);
1611 if (bc_length == 0) {
1612 // More complicated bytecodes report a length of zero so
1613 // we have to try again a slightly different way.
1614 bc_length = Bytecodes::length_at(method(), bcp);
1615 }
1617 assert(bc_length != 0, "impossible bytecode length");
1619 switch (c) {
1620 case Bytecodes::_ldc:
1621 {
1622 int cp_index = *(bcp + 1);
1623 int new_index = find_new_index(cp_index);
1625 if (StressLdcRewrite && new_index == 0) {
1626 // If we are stressing ldc -> ldc_w rewriting, then we
1627 // always need a new_index value.
1628 new_index = cp_index;
1629 }
1630 if (new_index != 0) {
1631 // the original index is mapped so we have more work to do
1632 if (!StressLdcRewrite && new_index <= max_jubyte) {
1633 // The new value can still use ldc instead of ldc_w
1634 // unless we are trying to stress ldc -> ldc_w rewriting
1635 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1636 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1637 bcp, cp_index, new_index));
1638 *(bcp + 1) = new_index;
1639 } else {
1640 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1641 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1642 Bytecodes::name(c), bcp, cp_index, new_index));
1643 // the new value needs ldc_w instead of ldc
1644 u_char inst_buffer[4]; // max instruction size is 4 bytes
1645 bcp = (address)inst_buffer;
1646 // construct new instruction sequence
1647 *bcp = Bytecodes::_ldc_w;
1648 bcp++;
1649 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1650 // See comment below for difference between put_Java_u2()
1651 // and put_native_u2().
1652 Bytes::put_Java_u2(bcp, new_index);
1654 Relocator rc(method, NULL /* no RelocatorListener needed */);
1655 methodHandle m;
1656 {
1657 Pause_No_Safepoint_Verifier pnsv(&nsv);
1659 // ldc is 2 bytes and ldc_w is 3 bytes
1660 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1661 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1662 guarantee(false, "insert_space_at() failed");
1663 }
1664 }
1666 // return the new method so that the caller can update
1667 // the containing class
1668 *new_method_p = method = m;
1669 // switch our bytecode processing loop from the old method
1670 // to the new method
1671 code_base = method->code_base();
1672 code_length = method->code_size();
1673 bcp = code_base + bci;
1674 c = (Bytecodes::Code)(*bcp);
1675 bc_length = Bytecodes::length_for(c);
1676 assert(bc_length != 0, "sanity check");
1677 } // end we need ldc_w instead of ldc
1678 } // end if there is a mapped index
1679 } break;
1681 // these bytecodes have a two-byte constant pool index
1682 case Bytecodes::_anewarray : // fall through
1683 case Bytecodes::_checkcast : // fall through
1684 case Bytecodes::_getfield : // fall through
1685 case Bytecodes::_getstatic : // fall through
1686 case Bytecodes::_instanceof : // fall through
1687 case Bytecodes::_invokedynamic : // fall through
1688 case Bytecodes::_invokeinterface: // fall through
1689 case Bytecodes::_invokespecial : // fall through
1690 case Bytecodes::_invokestatic : // fall through
1691 case Bytecodes::_invokevirtual : // fall through
1692 case Bytecodes::_ldc_w : // fall through
1693 case Bytecodes::_ldc2_w : // fall through
1694 case Bytecodes::_multianewarray : // fall through
1695 case Bytecodes::_new : // fall through
1696 case Bytecodes::_putfield : // fall through
1697 case Bytecodes::_putstatic :
1698 {
1699 address p = bcp + 1;
1700 int cp_index = Bytes::get_Java_u2(p);
1701 int new_index = find_new_index(cp_index);
1702 if (new_index != 0) {
1703 // the original index is mapped so update w/ new value
1704 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1705 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1706 bcp, cp_index, new_index));
1707 // Rewriter::rewrite_method() uses put_native_u2() in this
1708 // situation because it is reusing the constant pool index
1709 // location for a native index into the ConstantPoolCache.
1710 // Since we are updating the constant pool index prior to
1711 // verification and ConstantPoolCache initialization, we
1712 // need to keep the new index in Java byte order.
1713 Bytes::put_Java_u2(p, new_index);
1714 }
1715 } break;
1716 }
1717 } // end for each bytecode
1719 // We also need to rewrite the parameter name indexes, if there is
1720 // method parameter data present
1721 if(method->has_method_parameters()) {
1722 const int len = method->method_parameters_length();
1723 MethodParametersElement* elem = method->method_parameters_start();
1725 for (int i = 0; i < len; i++) {
1726 const u2 cp_index = elem[i].name_cp_index;
1727 elem[i].name_cp_index = find_new_index(cp_index);
1728 }
1729 }
1730 } // end rewrite_cp_refs_in_method()
1733 // Rewrite constant pool references in the class_annotations field.
1734 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1735 instanceKlassHandle scratch_class, TRAPS) {
1737 AnnotationArray* class_annotations = scratch_class->class_annotations();
1738 if (class_annotations == NULL || class_annotations->length() == 0) {
1739 // no class_annotations so nothing to do
1740 return true;
1741 }
1743 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1744 ("class_annotations length=%d", class_annotations->length()));
1746 int byte_i = 0; // byte index into class_annotations
1747 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1748 THREAD);
1749 }
1752 // Rewrite constant pool references in an annotations typeArray. This
1753 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1754 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1755 //
1756 // annotations_typeArray {
1757 // u2 num_annotations;
1758 // annotation annotations[num_annotations];
1759 // }
1760 //
1761 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1762 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1764 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1765 // not enough room for num_annotations field
1766 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1767 ("length() is too small for num_annotations field"));
1768 return false;
1769 }
1771 u2 num_annotations = Bytes::get_Java_u2((address)
1772 annotations_typeArray->adr_at(byte_i_ref));
1773 byte_i_ref += 2;
1775 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1776 ("num_annotations=%d", num_annotations));
1778 int calc_num_annotations = 0;
1779 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1780 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1781 byte_i_ref, THREAD)) {
1782 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1783 ("bad annotation_struct at %d", calc_num_annotations));
1784 // propagate failure back to caller
1785 return false;
1786 }
1787 }
1788 assert(num_annotations == calc_num_annotations, "sanity check");
1790 return true;
1791 } // end rewrite_cp_refs_in_annotations_typeArray()
1794 // Rewrite constant pool references in the annotation struct portion of
1795 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1796 // the 2nd-edition of the VM spec:
1797 //
1798 // struct annotation {
1799 // u2 type_index;
1800 // u2 num_element_value_pairs;
1801 // {
1802 // u2 element_name_index;
1803 // element_value value;
1804 // } element_value_pairs[num_element_value_pairs];
1805 // }
1806 //
1807 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1808 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1809 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1810 // not enough room for smallest annotation_struct
1811 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1812 ("length() is too small for annotation_struct"));
1813 return false;
1814 }
1816 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1817 byte_i_ref, "mapped old type_index=%d", THREAD);
1819 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1820 annotations_typeArray->adr_at(byte_i_ref));
1821 byte_i_ref += 2;
1823 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1824 ("type_index=%d num_element_value_pairs=%d", type_index,
1825 num_element_value_pairs));
1827 int calc_num_element_value_pairs = 0;
1828 for (; calc_num_element_value_pairs < num_element_value_pairs;
1829 calc_num_element_value_pairs++) {
1830 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1831 // not enough room for another element_name_index, let alone
1832 // the rest of another component
1833 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1834 ("length() is too small for element_name_index"));
1835 return false;
1836 }
1838 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1839 annotations_typeArray, byte_i_ref,
1840 "mapped old element_name_index=%d", THREAD);
1842 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1843 ("element_name_index=%d", element_name_index));
1845 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1846 byte_i_ref, THREAD)) {
1847 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1848 ("bad element_value at %d", calc_num_element_value_pairs));
1849 // propagate failure back to caller
1850 return false;
1851 }
1852 } // end for each component
1853 assert(num_element_value_pairs == calc_num_element_value_pairs,
1854 "sanity check");
1856 return true;
1857 } // end rewrite_cp_refs_in_annotation_struct()
1860 // Rewrite a constant pool reference at the current position in
1861 // annotations_typeArray if needed. Returns the original constant
1862 // pool reference if a rewrite was not needed or the new constant
1863 // pool reference if a rewrite was needed.
1864 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1865 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1866 const char * trace_mesg, TRAPS) {
1868 address cp_index_addr = (address)
1869 annotations_typeArray->adr_at(byte_i_ref);
1870 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1871 u2 new_cp_index = find_new_index(old_cp_index);
1872 if (new_cp_index != 0) {
1873 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1874 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1875 old_cp_index = new_cp_index;
1876 }
1877 byte_i_ref += 2;
1878 return old_cp_index;
1879 }
1882 // Rewrite constant pool references in the element_value portion of an
1883 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1884 // the 2nd-edition of the VM spec:
1885 //
1886 // struct element_value {
1887 // u1 tag;
1888 // union {
1889 // u2 const_value_index;
1890 // {
1891 // u2 type_name_index;
1892 // u2 const_name_index;
1893 // } enum_const_value;
1894 // u2 class_info_index;
1895 // annotation annotation_value;
1896 // struct {
1897 // u2 num_values;
1898 // element_value values[num_values];
1899 // } array_value;
1900 // } value;
1901 // }
1902 //
1903 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1904 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1906 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1907 // not enough room for a tag let alone the rest of an element_value
1908 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1909 ("length() is too small for a tag"));
1910 return false;
1911 }
1913 u1 tag = annotations_typeArray->at(byte_i_ref);
1914 byte_i_ref++;
1915 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1917 switch (tag) {
1918 // These BaseType tag values are from Table 4.2 in VM spec:
1919 case 'B': // byte
1920 case 'C': // char
1921 case 'D': // double
1922 case 'F': // float
1923 case 'I': // int
1924 case 'J': // long
1925 case 'S': // short
1926 case 'Z': // boolean
1928 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1929 // the VM spec:
1930 case 's':
1931 {
1932 // For the above tag values (including the BaseType values),
1933 // value.const_value_index is right union field.
1935 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1936 // not enough room for a const_value_index
1937 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1938 ("length() is too small for a const_value_index"));
1939 return false;
1940 }
1942 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1943 annotations_typeArray, byte_i_ref,
1944 "mapped old const_value_index=%d", THREAD);
1946 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1947 ("const_value_index=%d", const_value_index));
1948 } break;
1950 case 'e':
1951 {
1952 // for the above tag value, value.enum_const_value is right union field
1954 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1955 // not enough room for a enum_const_value
1956 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1957 ("length() is too small for a enum_const_value"));
1958 return false;
1959 }
1961 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1962 annotations_typeArray, byte_i_ref,
1963 "mapped old type_name_index=%d", THREAD);
1965 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1966 annotations_typeArray, byte_i_ref,
1967 "mapped old const_name_index=%d", THREAD);
1969 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1970 ("type_name_index=%d const_name_index=%d", type_name_index,
1971 const_name_index));
1972 } break;
1974 case 'c':
1975 {
1976 // for the above tag value, value.class_info_index is right union field
1978 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1979 // not enough room for a class_info_index
1980 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1981 ("length() is too small for a class_info_index"));
1982 return false;
1983 }
1985 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1986 annotations_typeArray, byte_i_ref,
1987 "mapped old class_info_index=%d", THREAD);
1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1990 ("class_info_index=%d", class_info_index));
1991 } break;
1993 case '@':
1994 // For the above tag value, value.attr_value is the right union
1995 // field. This is a nested annotation.
1996 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1997 byte_i_ref, THREAD)) {
1998 // propagate failure back to caller
1999 return false;
2000 }
2001 break;
2003 case '[':
2004 {
2005 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2006 // not enough room for a num_values field
2007 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2008 ("length() is too small for a num_values field"));
2009 return false;
2010 }
2012 // For the above tag value, value.array_value is the right union
2013 // field. This is an array of nested element_value.
2014 u2 num_values = Bytes::get_Java_u2((address)
2015 annotations_typeArray->adr_at(byte_i_ref));
2016 byte_i_ref += 2;
2017 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2019 int calc_num_values = 0;
2020 for (; calc_num_values < num_values; calc_num_values++) {
2021 if (!rewrite_cp_refs_in_element_value(
2022 annotations_typeArray, byte_i_ref, THREAD)) {
2023 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2024 ("bad nested element_value at %d", calc_num_values));
2025 // propagate failure back to caller
2026 return false;
2027 }
2028 }
2029 assert(num_values == calc_num_values, "sanity check");
2030 } break;
2032 default:
2033 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2034 return false;
2035 } // end decode tag field
2037 return true;
2038 } // end rewrite_cp_refs_in_element_value()
2041 // Rewrite constant pool references in a fields_annotations field.
2042 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2043 instanceKlassHandle scratch_class, TRAPS) {
2045 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2047 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2048 // no fields_annotations so nothing to do
2049 return true;
2050 }
2052 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2053 ("fields_annotations length=%d", fields_annotations->length()));
2055 for (int i = 0; i < fields_annotations->length(); i++) {
2056 AnnotationArray* field_annotations = fields_annotations->at(i);
2057 if (field_annotations == NULL || field_annotations->length() == 0) {
2058 // this field does not have any annotations so skip it
2059 continue;
2060 }
2062 int byte_i = 0; // byte index into field_annotations
2063 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2064 THREAD)) {
2065 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2066 ("bad field_annotations at %d", i));
2067 // propagate failure back to caller
2068 return false;
2069 }
2070 }
2072 return true;
2073 } // end rewrite_cp_refs_in_fields_annotations()
2076 // Rewrite constant pool references in a methods_annotations field.
2077 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2078 instanceKlassHandle scratch_class, TRAPS) {
2080 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2081 Method* m = scratch_class->methods()->at(i);
2082 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2084 if (method_annotations == NULL || method_annotations->length() == 0) {
2085 // this method does not have any annotations so skip it
2086 continue;
2087 }
2089 int byte_i = 0; // byte index into method_annotations
2090 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2091 THREAD)) {
2092 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2093 ("bad method_annotations at %d", i));
2094 // propagate failure back to caller
2095 return false;
2096 }
2097 }
2099 return true;
2100 } // end rewrite_cp_refs_in_methods_annotations()
2103 // Rewrite constant pool references in a methods_parameter_annotations
2104 // field. This "structure" is adapted from the
2105 // RuntimeVisibleParameterAnnotations_attribute described in section
2106 // 4.8.17 of the 2nd-edition of the VM spec:
2107 //
2108 // methods_parameter_annotations_typeArray {
2109 // u1 num_parameters;
2110 // {
2111 // u2 num_annotations;
2112 // annotation annotations[num_annotations];
2113 // } parameter_annotations[num_parameters];
2114 // }
2115 //
2116 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2117 instanceKlassHandle scratch_class, TRAPS) {
2119 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2120 Method* m = scratch_class->methods()->at(i);
2121 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2122 if (method_parameter_annotations == NULL
2123 || method_parameter_annotations->length() == 0) {
2124 // this method does not have any parameter annotations so skip it
2125 continue;
2126 }
2128 if (method_parameter_annotations->length() < 1) {
2129 // not enough room for a num_parameters field
2130 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2131 ("length() is too small for a num_parameters field at %d", i));
2132 return false;
2133 }
2135 int byte_i = 0; // byte index into method_parameter_annotations
2137 u1 num_parameters = method_parameter_annotations->at(byte_i);
2138 byte_i++;
2140 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2141 ("num_parameters=%d", num_parameters));
2143 int calc_num_parameters = 0;
2144 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2145 if (!rewrite_cp_refs_in_annotations_typeArray(
2146 method_parameter_annotations, byte_i, THREAD)) {
2147 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2148 ("bad method_parameter_annotations at %d", calc_num_parameters));
2149 // propagate failure back to caller
2150 return false;
2151 }
2152 }
2153 assert(num_parameters == calc_num_parameters, "sanity check");
2154 }
2156 return true;
2157 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2160 // Rewrite constant pool references in a methods_default_annotations
2161 // field. This "structure" is adapted from the AnnotationDefault_attribute
2162 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2163 //
2164 // methods_default_annotations_typeArray {
2165 // element_value default_value;
2166 // }
2167 //
2168 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2169 instanceKlassHandle scratch_class, TRAPS) {
2171 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2172 Method* m = scratch_class->methods()->at(i);
2173 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2174 if (method_default_annotations == NULL
2175 || method_default_annotations->length() == 0) {
2176 // this method does not have any default annotations so skip it
2177 continue;
2178 }
2180 int byte_i = 0; // byte index into method_default_annotations
2182 if (!rewrite_cp_refs_in_element_value(
2183 method_default_annotations, byte_i, THREAD)) {
2184 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2185 ("bad default element_value at %d", i));
2186 // propagate failure back to caller
2187 return false;
2188 }
2189 }
2191 return true;
2192 } // end rewrite_cp_refs_in_methods_default_annotations()
2195 // Rewrite constant pool references in the method's stackmap table.
2196 // These "structures" are adapted from the StackMapTable_attribute that
2197 // is described in section 4.8.4 of the 6.0 version of the VM spec
2198 // (dated 2005.10.26):
2199 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2200 //
2201 // stack_map {
2202 // u2 number_of_entries;
2203 // stack_map_frame entries[number_of_entries];
2204 // }
2205 //
2206 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2207 methodHandle method, TRAPS) {
2209 if (!method->has_stackmap_table()) {
2210 return;
2211 }
2213 AnnotationArray* stackmap_data = method->stackmap_data();
2214 address stackmap_p = (address)stackmap_data->adr_at(0);
2215 address stackmap_end = stackmap_p + stackmap_data->length();
2217 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2218 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2219 stackmap_p += 2;
2221 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2222 ("number_of_entries=%u", number_of_entries));
2224 // walk through each stack_map_frame
2225 u2 calc_number_of_entries = 0;
2226 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2227 // The stack_map_frame structure is a u1 frame_type followed by
2228 // 0 or more bytes of data:
2229 //
2230 // union stack_map_frame {
2231 // same_frame;
2232 // same_locals_1_stack_item_frame;
2233 // same_locals_1_stack_item_frame_extended;
2234 // chop_frame;
2235 // same_frame_extended;
2236 // append_frame;
2237 // full_frame;
2238 // }
2240 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2241 // The Linux compiler does not like frame_type to be u1 or u2. It
2242 // issues the following warning for the first if-statement below:
2243 //
2244 // "warning: comparison is always true due to limited range of data type"
2245 //
2246 u4 frame_type = *stackmap_p;
2247 stackmap_p++;
2249 // same_frame {
2250 // u1 frame_type = SAME; /* 0-63 */
2251 // }
2252 if (frame_type >= 0 && frame_type <= 63) {
2253 // nothing more to do for same_frame
2254 }
2256 // same_locals_1_stack_item_frame {
2257 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2258 // verification_type_info stack[1];
2259 // }
2260 else if (frame_type >= 64 && frame_type <= 127) {
2261 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2262 calc_number_of_entries, frame_type, THREAD);
2263 }
2265 // reserved for future use
2266 else if (frame_type >= 128 && frame_type <= 246) {
2267 // nothing more to do for reserved frame_types
2268 }
2270 // same_locals_1_stack_item_frame_extended {
2271 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2272 // u2 offset_delta;
2273 // verification_type_info stack[1];
2274 // }
2275 else if (frame_type == 247) {
2276 stackmap_p += 2;
2277 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2278 calc_number_of_entries, frame_type, THREAD);
2279 }
2281 // chop_frame {
2282 // u1 frame_type = CHOP; /* 248-250 */
2283 // u2 offset_delta;
2284 // }
2285 else if (frame_type >= 248 && frame_type <= 250) {
2286 stackmap_p += 2;
2287 }
2289 // same_frame_extended {
2290 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2291 // u2 offset_delta;
2292 // }
2293 else if (frame_type == 251) {
2294 stackmap_p += 2;
2295 }
2297 // append_frame {
2298 // u1 frame_type = APPEND; /* 252-254 */
2299 // u2 offset_delta;
2300 // verification_type_info locals[frame_type - 251];
2301 // }
2302 else if (frame_type >= 252 && frame_type <= 254) {
2303 assert(stackmap_p + 2 <= stackmap_end,
2304 "no room for offset_delta");
2305 stackmap_p += 2;
2306 u1 len = frame_type - 251;
2307 for (u1 i = 0; i < len; i++) {
2308 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2309 calc_number_of_entries, frame_type, THREAD);
2310 }
2311 }
2313 // full_frame {
2314 // u1 frame_type = FULL_FRAME; /* 255 */
2315 // u2 offset_delta;
2316 // u2 number_of_locals;
2317 // verification_type_info locals[number_of_locals];
2318 // u2 number_of_stack_items;
2319 // verification_type_info stack[number_of_stack_items];
2320 // }
2321 else if (frame_type == 255) {
2322 assert(stackmap_p + 2 + 2 <= stackmap_end,
2323 "no room for smallest full_frame");
2324 stackmap_p += 2;
2326 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2327 stackmap_p += 2;
2329 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2330 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2331 calc_number_of_entries, frame_type, THREAD);
2332 }
2334 // Use the largest size for the number_of_stack_items, but only get
2335 // the right number of bytes.
2336 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2337 stackmap_p += 2;
2339 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2340 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2341 calc_number_of_entries, frame_type, THREAD);
2342 }
2343 }
2344 } // end while there is a stack_map_frame
2345 assert(number_of_entries == calc_number_of_entries, "sanity check");
2346 } // end rewrite_cp_refs_in_stack_map_table()
2349 // Rewrite constant pool references in the verification type info
2350 // portion of the method's stackmap table. These "structures" are
2351 // adapted from the StackMapTable_attribute that is described in
2352 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2353 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2354 //
2355 // The verification_type_info structure is a u1 tag followed by 0 or
2356 // more bytes of data:
2357 //
2358 // union verification_type_info {
2359 // Top_variable_info;
2360 // Integer_variable_info;
2361 // Float_variable_info;
2362 // Long_variable_info;
2363 // Double_variable_info;
2364 // Null_variable_info;
2365 // UninitializedThis_variable_info;
2366 // Object_variable_info;
2367 // Uninitialized_variable_info;
2368 // }
2369 //
2370 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2371 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2372 u1 frame_type, TRAPS) {
2374 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2375 u1 tag = *stackmap_p_ref;
2376 stackmap_p_ref++;
2378 switch (tag) {
2379 // Top_variable_info {
2380 // u1 tag = ITEM_Top; /* 0 */
2381 // }
2382 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2383 case 0: // fall through
2385 // Integer_variable_info {
2386 // u1 tag = ITEM_Integer; /* 1 */
2387 // }
2388 case ITEM_Integer: // fall through
2390 // Float_variable_info {
2391 // u1 tag = ITEM_Float; /* 2 */
2392 // }
2393 case ITEM_Float: // fall through
2395 // Double_variable_info {
2396 // u1 tag = ITEM_Double; /* 3 */
2397 // }
2398 case ITEM_Double: // fall through
2400 // Long_variable_info {
2401 // u1 tag = ITEM_Long; /* 4 */
2402 // }
2403 case ITEM_Long: // fall through
2405 // Null_variable_info {
2406 // u1 tag = ITEM_Null; /* 5 */
2407 // }
2408 case ITEM_Null: // fall through
2410 // UninitializedThis_variable_info {
2411 // u1 tag = ITEM_UninitializedThis; /* 6 */
2412 // }
2413 case ITEM_UninitializedThis:
2414 // nothing more to do for the above tag types
2415 break;
2417 // Object_variable_info {
2418 // u1 tag = ITEM_Object; /* 7 */
2419 // u2 cpool_index;
2420 // }
2421 case ITEM_Object:
2422 {
2423 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2424 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2425 u2 new_cp_index = find_new_index(cpool_index);
2426 if (new_cp_index != 0) {
2427 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2428 ("mapped old cpool_index=%d", cpool_index));
2429 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2430 cpool_index = new_cp_index;
2431 }
2432 stackmap_p_ref += 2;
2434 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2435 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2436 frame_type, cpool_index));
2437 } break;
2439 // Uninitialized_variable_info {
2440 // u1 tag = ITEM_Uninitialized; /* 8 */
2441 // u2 offset;
2442 // }
2443 case ITEM_Uninitialized:
2444 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2445 stackmap_p_ref += 2;
2446 break;
2448 default:
2449 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2450 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2451 ShouldNotReachHere();
2452 break;
2453 } // end switch (tag)
2454 } // end rewrite_cp_refs_in_verification_type_info()
2457 // Change the constant pool associated with klass scratch_class to
2458 // scratch_cp. If shrink is true, then scratch_cp_length elements
2459 // are copied from scratch_cp to a smaller constant pool and the
2460 // smaller constant pool is associated with scratch_class.
2461 void VM_RedefineClasses::set_new_constant_pool(
2462 ClassLoaderData* loader_data,
2463 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2464 int scratch_cp_length, TRAPS) {
2465 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2467 // scratch_cp is a merged constant pool and has enough space for a
2468 // worst case merge situation. We want to associate the minimum
2469 // sized constant pool with the klass to save space.
2470 constantPoolHandle smaller_cp(THREAD,
2471 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD));
2473 // preserve version() value in the smaller copy
2474 int version = scratch_cp->version();
2475 assert(version != 0, "sanity check");
2476 smaller_cp->set_version(version);
2478 // attach klass to new constant pool
2479 // reference to the cp holder is needed for copy_operands()
2480 smaller_cp->set_pool_holder(scratch_class());
2482 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2483 scratch_cp = smaller_cp;
2485 // attach new constant pool to klass
2486 scratch_class->set_constants(scratch_cp());
2488 int i; // for portability
2490 // update each field in klass to use new constant pool indices as needed
2491 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2492 jshort cur_index = fs.name_index();
2493 jshort new_index = find_new_index(cur_index);
2494 if (new_index != 0) {
2495 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2496 ("field-name_index change: %d to %d", cur_index, new_index));
2497 fs.set_name_index(new_index);
2498 }
2499 cur_index = fs.signature_index();
2500 new_index = find_new_index(cur_index);
2501 if (new_index != 0) {
2502 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2503 ("field-signature_index change: %d to %d", cur_index, new_index));
2504 fs.set_signature_index(new_index);
2505 }
2506 cur_index = fs.initval_index();
2507 new_index = find_new_index(cur_index);
2508 if (new_index != 0) {
2509 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2510 ("field-initval_index change: %d to %d", cur_index, new_index));
2511 fs.set_initval_index(new_index);
2512 }
2513 cur_index = fs.generic_signature_index();
2514 new_index = find_new_index(cur_index);
2515 if (new_index != 0) {
2516 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2517 ("field-generic_signature change: %d to %d", cur_index, new_index));
2518 fs.set_generic_signature_index(new_index);
2519 }
2520 } // end for each field
2522 // Update constant pool indices in the inner classes info to use
2523 // new constant indices as needed. The inner classes info is a
2524 // quadruple:
2525 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2526 InnerClassesIterator iter(scratch_class);
2527 for (; !iter.done(); iter.next()) {
2528 int cur_index = iter.inner_class_info_index();
2529 if (cur_index == 0) {
2530 continue; // JVM spec. allows null inner class refs so skip it
2531 }
2532 int new_index = find_new_index(cur_index);
2533 if (new_index != 0) {
2534 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2535 ("inner_class_info change: %d to %d", cur_index, new_index));
2536 iter.set_inner_class_info_index(new_index);
2537 }
2538 cur_index = iter.outer_class_info_index();
2539 new_index = find_new_index(cur_index);
2540 if (new_index != 0) {
2541 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2542 ("outer_class_info change: %d to %d", cur_index, new_index));
2543 iter.set_outer_class_info_index(new_index);
2544 }
2545 cur_index = iter.inner_name_index();
2546 new_index = find_new_index(cur_index);
2547 if (new_index != 0) {
2548 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2549 ("inner_name change: %d to %d", cur_index, new_index));
2550 iter.set_inner_name_index(new_index);
2551 }
2552 } // end for each inner class
2554 // Attach each method in klass to the new constant pool and update
2555 // to use new constant pool indices as needed:
2556 Array<Method*>* methods = scratch_class->methods();
2557 for (i = methods->length() - 1; i >= 0; i--) {
2558 methodHandle method(THREAD, methods->at(i));
2559 method->set_constants(scratch_cp());
2561 int new_index = find_new_index(method->name_index());
2562 if (new_index != 0) {
2563 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2564 ("method-name_index change: %d to %d", method->name_index(),
2565 new_index));
2566 method->set_name_index(new_index);
2567 }
2568 new_index = find_new_index(method->signature_index());
2569 if (new_index != 0) {
2570 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2571 ("method-signature_index change: %d to %d",
2572 method->signature_index(), new_index));
2573 method->set_signature_index(new_index);
2574 }
2575 new_index = find_new_index(method->generic_signature_index());
2576 if (new_index != 0) {
2577 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2578 ("method-generic_signature_index change: %d to %d",
2579 method->generic_signature_index(), new_index));
2580 method->set_generic_signature_index(new_index);
2581 }
2583 // Update constant pool indices in the method's checked exception
2584 // table to use new constant indices as needed.
2585 int cext_length = method->checked_exceptions_length();
2586 if (cext_length > 0) {
2587 CheckedExceptionElement * cext_table =
2588 method->checked_exceptions_start();
2589 for (int j = 0; j < cext_length; j++) {
2590 int cur_index = cext_table[j].class_cp_index;
2591 int new_index = find_new_index(cur_index);
2592 if (new_index != 0) {
2593 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2594 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2595 cext_table[j].class_cp_index = (u2)new_index;
2596 }
2597 } // end for each checked exception table entry
2598 } // end if there are checked exception table entries
2600 // Update each catch type index in the method's exception table
2601 // to use new constant pool indices as needed. The exception table
2602 // holds quadruple entries of the form:
2603 // (beg_bci, end_bci, handler_bci, klass_index)
2605 ExceptionTable ex_table(method());
2606 int ext_length = ex_table.length();
2608 for (int j = 0; j < ext_length; j ++) {
2609 int cur_index = ex_table.catch_type_index(j);
2610 int new_index = find_new_index(cur_index);
2611 if (new_index != 0) {
2612 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2613 ("ext-klass_index change: %d to %d", cur_index, new_index));
2614 ex_table.set_catch_type_index(j, new_index);
2615 }
2616 } // end for each exception table entry
2618 // Update constant pool indices in the method's local variable
2619 // table to use new constant indices as needed. The local variable
2620 // table hold sextuple entries of the form:
2621 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2622 int lvt_length = method->localvariable_table_length();
2623 if (lvt_length > 0) {
2624 LocalVariableTableElement * lv_table =
2625 method->localvariable_table_start();
2626 for (int j = 0; j < lvt_length; j++) {
2627 int cur_index = lv_table[j].name_cp_index;
2628 int new_index = find_new_index(cur_index);
2629 if (new_index != 0) {
2630 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2631 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2632 lv_table[j].name_cp_index = (u2)new_index;
2633 }
2634 cur_index = lv_table[j].descriptor_cp_index;
2635 new_index = find_new_index(cur_index);
2636 if (new_index != 0) {
2637 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2638 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2639 new_index));
2640 lv_table[j].descriptor_cp_index = (u2)new_index;
2641 }
2642 cur_index = lv_table[j].signature_cp_index;
2643 new_index = find_new_index(cur_index);
2644 if (new_index != 0) {
2645 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2646 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2647 lv_table[j].signature_cp_index = (u2)new_index;
2648 }
2649 } // end for each local variable table entry
2650 } // end if there are local variable table entries
2652 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2653 } // end for each method
2654 } // end set_new_constant_pool()
2657 // Unevolving classes may point to methods of the_class directly
2658 // from their constant pool caches, itables, and/or vtables. We
2659 // use the ClassLoaderDataGraph::classes_do() facility and this helper
2660 // to fix up these pointers.
2662 // Adjust cpools and vtables closure
2663 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
2665 // This is a very busy routine. We don't want too much tracing
2666 // printed out.
2667 bool trace_name_printed = false;
2669 // Very noisy: only enable this call if you are trying to determine
2670 // that a specific class gets found by this routine.
2671 // RC_TRACE macro has an embedded ResourceMark
2672 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2673 // ("adjust check: name=%s", k->external_name()));
2674 // trace_name_printed = true;
2676 // If the class being redefined is java.lang.Object, we need to fix all
2677 // array class vtables also
2678 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
2679 k->vtable()->adjust_method_entries(_matching_old_methods,
2680 _matching_new_methods,
2681 _matching_methods_length,
2682 &trace_name_printed);
2683 } else if (k->oop_is_instance()) {
2684 HandleMark hm(_thread);
2685 InstanceKlass *ik = InstanceKlass::cast(k);
2687 // HotSpot specific optimization! HotSpot does not currently
2688 // support delegation from the bootstrap class loader to a
2689 // user-defined class loader. This means that if the bootstrap
2690 // class loader is the initiating class loader, then it will also
2691 // be the defining class loader. This also means that classes
2692 // loaded by the bootstrap class loader cannot refer to classes
2693 // loaded by a user-defined class loader. Note: a user-defined
2694 // class loader can delegate to the bootstrap class loader.
2695 //
2696 // If the current class being redefined has a user-defined class
2697 // loader as its defining class loader, then we can skip all
2698 // classes loaded by the bootstrap class loader.
2699 bool is_user_defined =
2700 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2701 if (is_user_defined && ik->class_loader() == NULL) {
2702 return;
2703 }
2705 // Fix the vtable embedded in the_class and subclasses of the_class,
2706 // if one exists. We discard scratch_class and we don't keep an
2707 // InstanceKlass around to hold obsolete methods so we don't have
2708 // any other InstanceKlass embedded vtables to update. The vtable
2709 // holds the Method*s for virtual (but not final) methods.
2710 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2711 // ik->vtable() creates a wrapper object; rm cleans it up
2712 ResourceMark rm(_thread);
2713 ik->vtable()->adjust_method_entries(_matching_old_methods,
2714 _matching_new_methods,
2715 _matching_methods_length,
2716 &trace_name_printed);
2717 }
2719 // If the current class has an itable and we are either redefining an
2720 // interface or if the current class is a subclass of the_class, then
2721 // we potentially have to fix the itable. If we are redefining an
2722 // interface, then we have to call adjust_method_entries() for
2723 // every InstanceKlass that has an itable since there isn't a
2724 // subclass relationship between an interface and an InstanceKlass.
2725 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2726 || ik->is_subclass_of(_the_class_oop))) {
2727 // ik->itable() creates a wrapper object; rm cleans it up
2728 ResourceMark rm(_thread);
2729 ik->itable()->adjust_method_entries(_matching_old_methods,
2730 _matching_new_methods,
2731 _matching_methods_length,
2732 &trace_name_printed);
2733 }
2735 // The constant pools in other classes (other_cp) can refer to
2736 // methods in the_class. We have to update method information in
2737 // other_cp's cache. If other_cp has a previous version, then we
2738 // have to repeat the process for each previous version. The
2739 // constant pool cache holds the Method*s for non-virtual
2740 // methods and for virtual, final methods.
2741 //
2742 // Special case: if the current class is the_class, then new_cp
2743 // has already been attached to the_class and old_cp has already
2744 // been added as a previous version. The new_cp doesn't have any
2745 // cached references to old methods so it doesn't need to be
2746 // updated. We can simply start with the previous version(s) in
2747 // that case.
2748 constantPoolHandle other_cp;
2749 ConstantPoolCache* cp_cache;
2751 if (ik != _the_class_oop) {
2752 // this klass' constant pool cache may need adjustment
2753 other_cp = constantPoolHandle(ik->constants());
2754 cp_cache = other_cp->cache();
2755 if (cp_cache != NULL) {
2756 cp_cache->adjust_method_entries(_matching_old_methods,
2757 _matching_new_methods,
2758 _matching_methods_length,
2759 &trace_name_printed);
2760 }
2761 }
2762 {
2763 ResourceMark rm(_thread);
2764 // PreviousVersionInfo objects returned via PreviousVersionWalker
2765 // contain a GrowableArray of handles. We have to clean up the
2766 // GrowableArray _after_ the PreviousVersionWalker destructor
2767 // has destroyed the handles.
2768 {
2769 // the previous versions' constant pool caches may need adjustment
2770 PreviousVersionWalker pvw(ik);
2771 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2772 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2773 other_cp = pv_info->prev_constant_pool_handle();
2774 cp_cache = other_cp->cache();
2775 if (cp_cache != NULL) {
2776 cp_cache->adjust_method_entries(_matching_old_methods,
2777 _matching_new_methods,
2778 _matching_methods_length,
2779 &trace_name_printed);
2780 }
2781 }
2782 } // pvw is cleaned up
2783 } // rm is cleaned up
2784 }
2785 }
2787 void VM_RedefineClasses::update_jmethod_ids() {
2788 for (int j = 0; j < _matching_methods_length; ++j) {
2789 Method* old_method = _matching_old_methods[j];
2790 jmethodID jmid = old_method->find_jmethod_id_or_null();
2791 if (jmid != NULL) {
2792 // There is a jmethodID, change it to point to the new method
2793 methodHandle new_method_h(_matching_new_methods[j]);
2794 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2795 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2796 "should be replaced");
2797 }
2798 }
2799 }
2801 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2802 BitMap *emcp_methods, int * emcp_method_count_p) {
2803 *emcp_method_count_p = 0;
2804 int obsolete_count = 0;
2805 int old_index = 0;
2806 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2807 Method* old_method = _matching_old_methods[j];
2808 Method* new_method = _matching_new_methods[j];
2809 Method* old_array_method;
2811 // Maintain an old_index into the _old_methods array by skipping
2812 // deleted methods
2813 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2814 ++old_index;
2815 }
2817 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2818 // The EMCP definition from JSR-163 requires the bytecodes to be
2819 // the same with the exception of constant pool indices which may
2820 // differ. However, the constants referred to by those indices
2821 // must be the same.
2822 //
2823 // We use methods_EMCP() for comparison since constant pool
2824 // merging can remove duplicate constant pool entries that were
2825 // present in the old method and removed from the rewritten new
2826 // method. A faster binary comparison function would consider the
2827 // old and new methods to be different when they are actually
2828 // EMCP.
2829 //
2830 // The old and new methods are EMCP and you would think that we
2831 // could get rid of one of them here and now and save some space.
2832 // However, the concept of EMCP only considers the bytecodes and
2833 // the constant pool entries in the comparison. Other things,
2834 // e.g., the line number table (LNT) or the local variable table
2835 // (LVT) don't count in the comparison. So the new (and EMCP)
2836 // method can have a new LNT that we need so we can't just
2837 // overwrite the new method with the old method.
2838 //
2839 // When this routine is called, we have already attached the new
2840 // methods to the_class so the old methods are effectively
2841 // overwritten. However, if an old method is still executing,
2842 // then the old method cannot be collected until sometime after
2843 // the old method call has returned. So the overwriting of old
2844 // methods by new methods will save us space except for those
2845 // (hopefully few) old methods that are still executing.
2846 //
2847 // A method refers to a ConstMethod* and this presents another
2848 // possible avenue to space savings. The ConstMethod* in the
2849 // new method contains possibly new attributes (LNT, LVT, etc).
2850 // At first glance, it seems possible to save space by replacing
2851 // the ConstMethod* in the old method with the ConstMethod*
2852 // from the new method. The old and new methods would share the
2853 // same ConstMethod* and we would save the space occupied by
2854 // the old ConstMethod*. However, the ConstMethod* contains
2855 // a back reference to the containing method. Sharing the
2856 // ConstMethod* between two methods could lead to confusion in
2857 // the code that uses the back reference. This would lead to
2858 // brittle code that could be broken in non-obvious ways now or
2859 // in the future.
2860 //
2861 // Another possibility is to copy the ConstMethod* from the new
2862 // method to the old method and then overwrite the new method with
2863 // the old method. Since the ConstMethod* contains the bytecodes
2864 // for the method embedded in the oop, this option would change
2865 // the bytecodes out from under any threads executing the old
2866 // method and make the thread's bcp invalid. Since EMCP requires
2867 // that the bytecodes be the same modulo constant pool indices, it
2868 // is straight forward to compute the correct new bcp in the new
2869 // ConstMethod* from the old bcp in the old ConstMethod*. The
2870 // time consuming part would be searching all the frames in all
2871 // of the threads to find all of the calls to the old method.
2872 //
2873 // It looks like we will have to live with the limited savings
2874 // that we get from effectively overwriting the old methods
2875 // when the new methods are attached to the_class.
2877 // track which methods are EMCP for add_previous_version() call
2878 emcp_methods->set_bit(old_index);
2879 (*emcp_method_count_p)++;
2881 // An EMCP method is _not_ obsolete. An obsolete method has a
2882 // different jmethodID than the current method. An EMCP method
2883 // has the same jmethodID as the current method. Having the
2884 // same jmethodID for all EMCP versions of a method allows for
2885 // a consistent view of the EMCP methods regardless of which
2886 // EMCP method you happen to have in hand. For example, a
2887 // breakpoint set in one EMCP method will work for all EMCP
2888 // versions of the method including the current one.
2889 } else {
2890 // mark obsolete methods as such
2891 old_method->set_is_obsolete();
2892 obsolete_count++;
2894 // obsolete methods need a unique idnum
2895 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2896 if (num != ConstMethod::UNSET_IDNUM) {
2897 // u2 old_num = old_method->method_idnum();
2898 old_method->set_method_idnum(num);
2899 // TO DO: attach obsolete annotations to obsolete method's new idnum
2900 }
2901 // With tracing we try not to "yack" too much. The position of
2902 // this trace assumes there are fewer obsolete methods than
2903 // EMCP methods.
2904 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2905 old_method->name()->as_C_string(),
2906 old_method->signature()->as_C_string()));
2907 }
2908 old_method->set_is_old();
2909 }
2910 for (int i = 0; i < _deleted_methods_length; ++i) {
2911 Method* old_method = _deleted_methods[i];
2913 assert(old_method->vtable_index() < 0,
2914 "cannot delete methods with vtable entries");;
2916 // Mark all deleted methods as old and obsolete
2917 old_method->set_is_old();
2918 old_method->set_is_obsolete();
2919 ++obsolete_count;
2920 // With tracing we try not to "yack" too much. The position of
2921 // this trace assumes there are fewer obsolete methods than
2922 // EMCP methods.
2923 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2924 old_method->name()->as_C_string(),
2925 old_method->signature()->as_C_string()));
2926 }
2927 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2928 "sanity check");
2929 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2930 obsolete_count));
2931 }
2933 // This internal class transfers the native function registration from old methods
2934 // to new methods. It is designed to handle both the simple case of unchanged
2935 // native methods and the complex cases of native method prefixes being added and/or
2936 // removed.
2937 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2938 //
2939 // This class is used after the new methods have been installed in "the_class".
2940 //
2941 // So, for example, the following must be handled. Where 'm' is a method and
2942 // a number followed by an underscore is a prefix.
2943 //
2944 // Old Name New Name
2945 // Simple transfer to new method m -> m
2946 // Add prefix m -> 1_m
2947 // Remove prefix 1_m -> m
2948 // Simultaneous add of prefixes m -> 3_2_1_m
2949 // Simultaneous removal of prefixes 3_2_1_m -> m
2950 // Simultaneous add and remove 1_m -> 2_m
2951 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2952 //
2953 class TransferNativeFunctionRegistration {
2954 private:
2955 instanceKlassHandle the_class;
2956 int prefix_count;
2957 char** prefixes;
2959 // Recursively search the binary tree of possibly prefixed method names.
2960 // Iteration could be used if all agents were well behaved. Full tree walk is
2961 // more resilent to agents not cleaning up intermediate methods.
2962 // Branch at each depth in the binary tree is:
2963 // (1) without the prefix.
2964 // (2) with the prefix.
2965 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2966 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
2967 Symbol* signature) {
2968 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2969 if (name_symbol != NULL) {
2970 Method* method = the_class()->lookup_method(name_symbol, signature);
2971 if (method != NULL) {
2972 // Even if prefixed, intermediate methods must exist.
2973 if (method->is_native()) {
2974 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2975 return method;
2976 }
2977 if (depth < prefix_count) {
2978 // Try applying further prefixes (other than this one).
2979 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
2980 if (method != NULL) {
2981 return method; // found
2982 }
2984 // Try adding this prefix to the method name and see if it matches
2985 // another method name.
2986 char* prefix = prefixes[depth];
2987 size_t prefix_len = strlen(prefix);
2988 size_t trial_len = name_len + prefix_len;
2989 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
2990 strcpy(trial_name_str, prefix);
2991 strcat(trial_name_str, name_str);
2992 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
2993 signature);
2994 if (method != NULL) {
2995 // If found along this branch, it was prefixed, mark as such
2996 method->set_is_prefixed_native();
2997 return method; // found
2998 }
2999 }
3000 }
3001 }
3002 return NULL; // This whole branch bore nothing
3003 }
3005 // Return the method name with old prefixes stripped away.
3006 char* method_name_without_prefixes(Method* method) {
3007 Symbol* name = method->name();
3008 char* name_str = name->as_utf8();
3010 // Old prefixing may be defunct, strip prefixes, if any.
3011 for (int i = prefix_count-1; i >= 0; i--) {
3012 char* prefix = prefixes[i];
3013 size_t prefix_len = strlen(prefix);
3014 if (strncmp(prefix, name_str, prefix_len) == 0) {
3015 name_str += prefix_len;
3016 }
3017 }
3018 return name_str;
3019 }
3021 // Strip any prefixes off the old native method, then try to find a
3022 // (possibly prefixed) new native that matches it.
3023 Method* strip_and_search_for_new_native(Method* method) {
3024 ResourceMark rm;
3025 char* name_str = method_name_without_prefixes(method);
3026 return search_prefix_name_space(0, name_str, strlen(name_str),
3027 method->signature());
3028 }
3030 public:
3032 // Construct a native method transfer processor for this class.
3033 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3034 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3036 the_class = _the_class;
3037 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3038 }
3040 // Attempt to transfer any of the old or deleted methods that are native
3041 void transfer_registrations(Method** old_methods, int methods_length) {
3042 for (int j = 0; j < methods_length; j++) {
3043 Method* old_method = old_methods[j];
3045 if (old_method->is_native() && old_method->has_native_function()) {
3046 Method* new_method = strip_and_search_for_new_native(old_method);
3047 if (new_method != NULL) {
3048 // Actually set the native function in the new method.
3049 // Redefine does not send events (except CFLH), certainly not this
3050 // behind the scenes re-registration.
3051 new_method->set_native_function(old_method->native_function(),
3052 !Method::native_bind_event_is_interesting);
3053 }
3054 }
3055 }
3056 }
3057 };
3059 // Don't lose the association between a native method and its JNI function.
3060 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3061 TransferNativeFunctionRegistration transfer(the_class);
3062 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3063 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3064 }
3066 // Deoptimize all compiled code that depends on this class.
3067 //
3068 // If the can_redefine_classes capability is obtained in the onload
3069 // phase then the compiler has recorded all dependencies from startup.
3070 // In that case we need only deoptimize and throw away all compiled code
3071 // that depends on the class.
3072 //
3073 // If can_redefine_classes is obtained sometime after the onload
3074 // phase then the dependency information may be incomplete. In that case
3075 // the first call to RedefineClasses causes all compiled code to be
3076 // thrown away. As can_redefine_classes has been obtained then
3077 // all future compilations will record dependencies so second and
3078 // subsequent calls to RedefineClasses need only throw away code
3079 // that depends on the class.
3080 //
3081 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3082 assert_locked_or_safepoint(Compile_lock);
3084 // All dependencies have been recorded from startup or this is a second or
3085 // subsequent use of RedefineClasses
3086 if (JvmtiExport::all_dependencies_are_recorded()) {
3087 Universe::flush_evol_dependents_on(k_h);
3088 } else {
3089 CodeCache::mark_all_nmethods_for_deoptimization();
3091 ResourceMark rm(THREAD);
3092 DeoptimizationMarker dm;
3094 // Deoptimize all activations depending on marked nmethods
3095 Deoptimization::deoptimize_dependents();
3097 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3098 CodeCache::make_marked_nmethods_not_entrant();
3100 // From now on we know that the dependency information is complete
3101 JvmtiExport::set_all_dependencies_are_recorded(true);
3102 }
3103 }
3105 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3106 Method* old_method;
3107 Method* new_method;
3109 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3110 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3111 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3112 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3114 _matching_methods_length = 0;
3115 _deleted_methods_length = 0;
3116 _added_methods_length = 0;
3118 int nj = 0;
3119 int oj = 0;
3120 while (true) {
3121 if (oj >= _old_methods->length()) {
3122 if (nj >= _new_methods->length()) {
3123 break; // we've looked at everything, done
3124 }
3125 // New method at the end
3126 new_method = _new_methods->at(nj);
3127 _added_methods[_added_methods_length++] = new_method;
3128 ++nj;
3129 } else if (nj >= _new_methods->length()) {
3130 // Old method, at the end, is deleted
3131 old_method = _old_methods->at(oj);
3132 _deleted_methods[_deleted_methods_length++] = old_method;
3133 ++oj;
3134 } else {
3135 old_method = _old_methods->at(oj);
3136 new_method = _new_methods->at(nj);
3137 if (old_method->name() == new_method->name()) {
3138 if (old_method->signature() == new_method->signature()) {
3139 _matching_old_methods[_matching_methods_length ] = old_method;
3140 _matching_new_methods[_matching_methods_length++] = new_method;
3141 ++nj;
3142 ++oj;
3143 } else {
3144 // added overloaded have already been moved to the end,
3145 // so this is a deleted overloaded method
3146 _deleted_methods[_deleted_methods_length++] = old_method;
3147 ++oj;
3148 }
3149 } else { // names don't match
3150 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3151 // new method
3152 _added_methods[_added_methods_length++] = new_method;
3153 ++nj;
3154 } else {
3155 // deleted method
3156 _deleted_methods[_deleted_methods_length++] = old_method;
3157 ++oj;
3158 }
3159 }
3160 }
3161 }
3162 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3163 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3164 }
3167 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3168 instanceKlassHandle scratch_class) {
3169 // Since there is currently no rewriting of type annotations indexes
3170 // into the CP, we null out type annotations on scratch_class before
3171 // we swap annotations with the_class rather than facing the
3172 // possibility of shipping annotations with broken indexes to
3173 // Java-land.
3174 ClassLoaderData* loader_data = scratch_class->class_loader_data();
3175 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
3176 if (new_class_type_annotations != NULL) {
3177 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
3178 scratch_class->annotations()->set_class_type_annotations(NULL);
3179 }
3180 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
3181 if (new_field_type_annotations != NULL) {
3182 Annotations::free_contents(loader_data, new_field_type_annotations);
3183 scratch_class->annotations()->set_fields_type_annotations(NULL);
3184 }
3186 // Swap annotation fields values
3187 Annotations* old_annotations = the_class->annotations();
3188 the_class->set_annotations(scratch_class->annotations());
3189 scratch_class->set_annotations(old_annotations);
3190 }
3193 // Install the redefinition of a class:
3194 // - house keeping (flushing breakpoints and caches, deoptimizing
3195 // dependent compiled code)
3196 // - replacing parts in the_class with parts from scratch_class
3197 // - adding a weak reference to track the obsolete but interesting
3198 // parts of the_class
3199 // - adjusting constant pool caches and vtables in other classes
3200 // that refer to methods in the_class. These adjustments use the
3201 // ClassLoaderDataGraph::classes_do() facility which only allows
3202 // a helper method to be specified. The interesting parameters
3203 // that we would like to pass to the helper method are saved in
3204 // static global fields in the VM operation.
3205 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3206 Klass* scratch_class_oop, TRAPS) {
3208 HandleMark hm(THREAD); // make sure handles from this call are freed
3209 RC_TIMER_START(_timer_rsc_phase1);
3211 instanceKlassHandle scratch_class(scratch_class_oop);
3213 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3214 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3215 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3217 // Remove all breakpoints in methods of this class
3218 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3219 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3221 if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
3222 // We are redefining java.lang.reflect.Method. Method.invoke() is
3223 // cached and users of the cache care about each active version of
3224 // the method so we have to track this previous version.
3225 // Do this before methods get switched
3226 Universe::reflect_invoke_cache()->add_previous_version(
3227 the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
3228 }
3230 // Deoptimize all compiled code that depends on this class
3231 flush_dependent_code(the_class, THREAD);
3233 _old_methods = the_class->methods();
3234 _new_methods = scratch_class->methods();
3235 _the_class_oop = the_class_oop;
3236 compute_added_deleted_matching_methods();
3237 update_jmethod_ids();
3239 // Attach new constant pool to the original klass. The original
3240 // klass still refers to the old constant pool (for now).
3241 scratch_class->constants()->set_pool_holder(the_class());
3243 #if 0
3244 // In theory, with constant pool merging in place we should be able
3245 // to save space by using the new, merged constant pool in place of
3246 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3247 // the klass version we are replacing now and any constant pool(s) in
3248 // previous versions of klass. Nice theory, doesn't work in practice.
3249 // When this code is enabled, even simple programs throw NullPointer
3250 // exceptions. I'm guessing that this is caused by some constant pool
3251 // cache difference between the new, merged constant pool and the
3252 // constant pool that was just being used by the klass. I'm keeping
3253 // this code around to archive the idea, but the code has to remain
3254 // disabled for now.
3256 // Attach each old method to the new constant pool. This can be
3257 // done here since we are past the bytecode verification and
3258 // constant pool optimization phases.
3259 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3260 Method* method = _old_methods->at(i);
3261 method->set_constants(scratch_class->constants());
3262 }
3264 {
3265 // walk all previous versions of the klass
3266 InstanceKlass *ik = (InstanceKlass *)the_class();
3267 PreviousVersionWalker pvw(ik);
3268 instanceKlassHandle ikh;
3269 do {
3270 ikh = pvw.next_previous_version();
3271 if (!ikh.is_null()) {
3272 ik = ikh();
3274 // attach previous version of klass to the new constant pool
3275 ik->set_constants(scratch_class->constants());
3277 // Attach each method in the previous version of klass to the
3278 // new constant pool
3279 Array<Method*>* prev_methods = ik->methods();
3280 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3281 Method* method = prev_methods->at(i);
3282 method->set_constants(scratch_class->constants());
3283 }
3284 }
3285 } while (!ikh.is_null());
3286 }
3287 #endif
3289 // Replace methods and constantpool
3290 the_class->set_methods(_new_methods);
3291 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3292 // and to be able to undo operation easily.
3294 ConstantPool* old_constants = the_class->constants();
3295 the_class->set_constants(scratch_class->constants());
3296 scratch_class->set_constants(old_constants); // See the previous comment.
3297 #if 0
3298 // We are swapping the guts of "the new class" with the guts of "the
3299 // class". Since the old constant pool has just been attached to "the
3300 // new class", it seems logical to set the pool holder in the old
3301 // constant pool also. However, doing this will change the observable
3302 // class hierarchy for any old methods that are still executing. A
3303 // method can query the identity of its "holder" and this query uses
3304 // the method's constant pool link to find the holder. The change in
3305 // holding class from "the class" to "the new class" can confuse
3306 // things.
3307 //
3308 // Setting the old constant pool's holder will also cause
3309 // verification done during vtable initialization below to fail.
3310 // During vtable initialization, the vtable's class is verified to be
3311 // a subtype of the method's holder. The vtable's class is "the
3312 // class" and the method's holder is gotten from the constant pool
3313 // link in the method itself. For "the class"'s directly implemented
3314 // methods, the method holder is "the class" itself (as gotten from
3315 // the new constant pool). The check works fine in this case. The
3316 // check also works fine for methods inherited from super classes.
3317 //
3318 // Miranda methods are a little more complicated. A miranda method is
3319 // provided by an interface when the class implementing the interface
3320 // does not provide its own method. These interfaces are implemented
3321 // internally as an InstanceKlass. These special instanceKlasses
3322 // share the constant pool of the class that "implements" the
3323 // interface. By sharing the constant pool, the method holder of a
3324 // miranda method is the class that "implements" the interface. In a
3325 // non-redefine situation, the subtype check works fine. However, if
3326 // the old constant pool's pool holder is modified, then the check
3327 // fails because there is no class hierarchy relationship between the
3328 // vtable's class and "the new class".
3330 old_constants->set_pool_holder(scratch_class());
3331 #endif
3333 // track which methods are EMCP for add_previous_version() call below
3334 BitMap emcp_methods(_old_methods->length());
3335 int emcp_method_count = 0;
3336 emcp_methods.clear(); // clears 0..(length() - 1)
3337 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3338 transfer_old_native_function_registrations(the_class);
3340 // The class file bytes from before any retransformable agents mucked
3341 // with them was cached on the scratch class, move to the_class.
3342 // Note: we still want to do this if nothing needed caching since it
3343 // should get cleared in the_class too.
3344 if (the_class->get_cached_class_file_bytes() == 0) {
3345 // the_class doesn't have a cache yet so copy it
3346 the_class->set_cached_class_file(
3347 scratch_class->get_cached_class_file_bytes(),
3348 scratch_class->get_cached_class_file_len());
3349 }
3350 #ifndef PRODUCT
3351 else {
3352 assert(the_class->get_cached_class_file_bytes() ==
3353 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3354 assert(the_class->get_cached_class_file_len() ==
3355 scratch_class->get_cached_class_file_len(), "cache lens must match");
3356 }
3357 #endif
3359 // NULL out in scratch class to not delete twice. The class to be redefined
3360 // always owns these bytes.
3361 scratch_class->set_cached_class_file(NULL, 0);
3363 // Replace inner_classes
3364 Array<u2>* old_inner_classes = the_class->inner_classes();
3365 the_class->set_inner_classes(scratch_class->inner_classes());
3366 scratch_class->set_inner_classes(old_inner_classes);
3368 // Initialize the vtable and interface table after
3369 // methods have been rewritten
3370 {
3371 ResourceMark rm(THREAD);
3372 // no exception should happen here since we explicitly
3373 // do not check loader constraints.
3374 // compare_and_normalize_class_versions has already checked:
3375 // - classloaders unchanged, signatures unchanged
3376 // - all instanceKlasses for redefined classes reused & contents updated
3377 the_class->vtable()->initialize_vtable(false, THREAD);
3378 the_class->itable()->initialize_itable(false, THREAD);
3379 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3380 }
3382 // Leave arrays of jmethodIDs and itable index cache unchanged
3384 // Copy the "source file name" attribute from new class version
3385 the_class->set_source_file_name(scratch_class->source_file_name());
3387 // Copy the "source debug extension" attribute from new class version
3388 the_class->set_source_debug_extension(
3389 scratch_class->source_debug_extension(),
3390 scratch_class->source_debug_extension() == NULL ? 0 :
3391 (int)strlen(scratch_class->source_debug_extension()));
3393 // Use of javac -g could be different in the old and the new
3394 if (scratch_class->access_flags().has_localvariable_table() !=
3395 the_class->access_flags().has_localvariable_table()) {
3397 AccessFlags flags = the_class->access_flags();
3398 if (scratch_class->access_flags().has_localvariable_table()) {
3399 flags.set_has_localvariable_table();
3400 } else {
3401 flags.clear_has_localvariable_table();
3402 }
3403 the_class->set_access_flags(flags);
3404 }
3406 swap_annotations(the_class, scratch_class);
3408 // Replace minor version number of class file
3409 u2 old_minor_version = the_class->minor_version();
3410 the_class->set_minor_version(scratch_class->minor_version());
3411 scratch_class->set_minor_version(old_minor_version);
3413 // Replace major version number of class file
3414 u2 old_major_version = the_class->major_version();
3415 the_class->set_major_version(scratch_class->major_version());
3416 scratch_class->set_major_version(old_major_version);
3418 // Replace CP indexes for class and name+type of enclosing method
3419 u2 old_class_idx = the_class->enclosing_method_class_index();
3420 u2 old_method_idx = the_class->enclosing_method_method_index();
3421 the_class->set_enclosing_method_indices(
3422 scratch_class->enclosing_method_class_index(),
3423 scratch_class->enclosing_method_method_index());
3424 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3426 // keep track of previous versions of this class
3427 the_class->add_previous_version(scratch_class, &emcp_methods,
3428 emcp_method_count);
3430 RC_TIMER_STOP(_timer_rsc_phase1);
3431 RC_TIMER_START(_timer_rsc_phase2);
3433 // Adjust constantpool caches and vtables for all classes
3434 // that reference methods of the evolved class.
3435 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
3436 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
3438 // JSR-292 support
3439 MemberNameTable* mnt = the_class->member_names();
3440 if (mnt != NULL) {
3441 bool trace_name_printed = false;
3442 mnt->adjust_method_entries(_matching_old_methods,
3443 _matching_new_methods,
3444 _matching_methods_length,
3445 &trace_name_printed);
3446 }
3448 // Fix Resolution Error table also to remove old constant pools
3449 SystemDictionary::delete_resolution_error(old_constants);
3451 if (the_class->oop_map_cache() != NULL) {
3452 // Flush references to any obsolete methods from the oop map cache
3453 // so that obsolete methods are not pinned.
3454 the_class->oop_map_cache()->flush_obsolete_entries();
3455 }
3457 // increment the classRedefinedCount field in the_class and in any
3458 // direct and indirect subclasses of the_class
3459 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3461 // RC_TRACE macro has an embedded ResourceMark
3462 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3463 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3464 the_class->external_name(),
3465 java_lang_Class::classRedefinedCount(the_class_mirror),
3466 os::available_memory() >> 10));
3468 RC_TIMER_STOP(_timer_rsc_phase2);
3469 } // end redefine_single_class()
3472 // Increment the classRedefinedCount field in the specific InstanceKlass
3473 // and in all direct and indirect subclasses.
3474 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3475 oop class_mirror = ik->java_mirror();
3476 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3477 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3478 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3480 if (class_oop != _the_class_oop) {
3481 // _the_class_oop count is printed at end of redefine_single_class()
3482 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3483 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3484 }
3486 for (Klass *subk = ik->subklass(); subk != NULL;
3487 subk = subk->next_sibling()) {
3488 if (subk->oop_is_instance()) {
3489 // Only update instanceKlasses
3490 InstanceKlass *subik = (InstanceKlass*)subk;
3491 // recursively do subclasses of the current subclass
3492 increment_class_counter(subik, THREAD);
3493 }
3494 }
3495 }
3497 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
3498 bool no_old_methods = true; // be optimistic
3500 // Both array and instance classes have vtables.
3501 // a vtable should never contain old or obsolete methods
3502 ResourceMark rm(_thread);
3503 if (k->vtable_length() > 0 &&
3504 !k->vtable()->check_no_old_or_obsolete_entries()) {
3505 if (RC_TRACE_ENABLED(0x00004000)) {
3506 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3507 ("klassVtable::check_no_old_or_obsolete_entries failure"
3508 " -- OLD or OBSOLETE method found -- class: %s",
3509 k->signature_name()));
3510 k->vtable()->dump_vtable();
3511 }
3512 no_old_methods = false;
3513 }
3515 if (k->oop_is_instance()) {
3516 HandleMark hm(_thread);
3517 InstanceKlass *ik = InstanceKlass::cast(k);
3519 // an itable should never contain old or obsolete methods
3520 if (ik->itable_length() > 0 &&
3521 !ik->itable()->check_no_old_or_obsolete_entries()) {
3522 if (RC_TRACE_ENABLED(0x00004000)) {
3523 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3524 ("klassItable::check_no_old_or_obsolete_entries failure"
3525 " -- OLD or OBSOLETE method found -- class: %s",
3526 ik->signature_name()));
3527 ik->itable()->dump_itable();
3528 }
3529 no_old_methods = false;
3530 }
3532 // the constant pool cache should never contain old or obsolete methods
3533 if (ik->constants() != NULL &&
3534 ik->constants()->cache() != NULL &&
3535 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
3536 if (RC_TRACE_ENABLED(0x00004000)) {
3537 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3538 ("cp-cache::check_no_old_or_obsolete_entries failure"
3539 " -- OLD or OBSOLETE method found -- class: %s",
3540 ik->signature_name()));
3541 ik->constants()->cache()->dump_cache();
3542 }
3543 no_old_methods = false;
3544 }
3545 }
3547 // print and fail guarantee if old methods are found.
3548 if (!no_old_methods) {
3549 if (RC_TRACE_ENABLED(0x00004000)) {
3550 dump_methods();
3551 } else {
3552 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
3553 "to see more info about the following guarantee() failure.");
3554 }
3555 guarantee(false, "OLD and/or OBSOLETE method(s) found");
3556 }
3557 }
3560 void VM_RedefineClasses::dump_methods() {
3561 int j;
3562 RC_TRACE(0x00004000, ("_old_methods --"));
3563 for (j = 0; j < _old_methods->length(); ++j) {
3564 Method* m = _old_methods->at(j);
3565 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3566 m->access_flags().print_on(tty);
3567 tty->print(" -- ");
3568 m->print_name(tty);
3569 tty->cr();
3570 }
3571 RC_TRACE(0x00004000, ("_new_methods --"));
3572 for (j = 0; j < _new_methods->length(); ++j) {
3573 Method* m = _new_methods->at(j);
3574 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3575 m->access_flags().print_on(tty);
3576 tty->print(" -- ");
3577 m->print_name(tty);
3578 tty->cr();
3579 }
3580 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
3581 for (j = 0; j < _matching_methods_length; ++j) {
3582 Method* m = _matching_old_methods[j];
3583 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3584 m->access_flags().print_on(tty);
3585 tty->print(" -- ");
3586 m->print_name(tty);
3587 tty->cr();
3588 m = _matching_new_methods[j];
3589 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
3590 m->access_flags().print_on(tty);
3591 tty->cr();
3592 }
3593 RC_TRACE(0x00004000, ("_deleted_methods --"));
3594 for (j = 0; j < _deleted_methods_length; ++j) {
3595 Method* m = _deleted_methods[j];
3596 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3597 m->access_flags().print_on(tty);
3598 tty->print(" -- ");
3599 m->print_name(tty);
3600 tty->cr();
3601 }
3602 RC_TRACE(0x00004000, ("_added_methods --"));
3603 for (j = 0; j < _added_methods_length; ++j) {
3604 Method* m = _added_methods[j];
3605 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3606 m->access_flags().print_on(tty);
3607 tty->print(" -- ");
3608 m->print_name(tty);
3609 tty->cr();
3610 }
3611 }