1 /*
2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classFileStream.hpp"
27 #include "classfile/metadataOnStackMark.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/verifier.hpp"
30 #include "code/codeCache.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "gc/shared/gcLocker.hpp"
33 #include "interpreter/oopMapCache.hpp"
34 #include "interpreter/rewriter.hpp"
35 #include "memory/metadataFactory.hpp"
36 #include "memory/metaspaceShared.hpp"
37 #include "memory/universe.inline.hpp"
38 #include "oops/fieldStreams.hpp"
39 #include "oops/klassVtable.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "prims/jvmtiImpl.hpp"
42 #include "prims/jvmtiRedefineClasses.hpp"
43 #include "prims/methodComparator.hpp"
44 #include "runtime/deoptimization.hpp"
45 #include "runtime/relocator.hpp"
46 #include "utilities/bitMap.inline.hpp"
47 #include "utilities/events.hpp"
48
49 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
50 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
51 Method** VM_RedefineClasses::_matching_old_methods = NULL;
52 Method** VM_RedefineClasses::_matching_new_methods = NULL;
53 Method** VM_RedefineClasses::_deleted_methods = NULL;
54 Method** VM_RedefineClasses::_added_methods = NULL;
55 int VM_RedefineClasses::_matching_methods_length = 0;
56 int VM_RedefineClasses::_deleted_methods_length = 0;
57 int VM_RedefineClasses::_added_methods_length = 0;
58 Klass* VM_RedefineClasses::_the_class_oop = NULL;
59
60
61 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
62 const jvmtiClassDefinition *class_defs,
63 JvmtiClassLoadKind class_load_kind) {
64 _class_count = class_count;
65 _class_defs = class_defs;
66 _class_load_kind = class_load_kind;
67 _res = JVMTI_ERROR_NONE;
68 }
69
70 bool VM_RedefineClasses::doit_prologue() {
71 if (_class_count == 0) {
72 _res = JVMTI_ERROR_NONE;
73 return false;
74 }
75 if (_class_defs == NULL) {
76 _res = JVMTI_ERROR_NULL_POINTER;
77 return false;
78 }
79 for (int i = 0; i < _class_count; i++) {
80 if (_class_defs[i].klass == NULL) {
81 _res = JVMTI_ERROR_INVALID_CLASS;
82 return false;
83 }
84 if (_class_defs[i].class_byte_count == 0) {
85 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
86 return false;
87 }
88 if (_class_defs[i].class_bytes == NULL) {
89 _res = JVMTI_ERROR_NULL_POINTER;
90 return false;
91 }
92 }
93
94 // Start timer after all the sanity checks; not quite accurate, but
95 // better than adding a bunch of stop() calls.
96 RC_TIMER_START(_timer_vm_op_prologue);
97
98 // We first load new class versions in the prologue, because somewhere down the
99 // call chain it is required that the current thread is a Java thread.
100 _res = load_new_class_versions(Thread::current());
101 if (_res != JVMTI_ERROR_NONE) {
102 // free any successfully created classes, since none are redefined
103 for (int i = 0; i < _class_count; i++) {
104 if (_scratch_classes[i] != NULL) {
105 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
106 // Free the memory for this class at class unloading time. Not before
107 // because CMS might think this is still live.
108 cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i]));
109 }
110 }
111 // Free os::malloc allocated memory in load_new_class_version.
112 os::free(_scratch_classes);
113 RC_TIMER_STOP(_timer_vm_op_prologue);
114 return false;
115 }
116
117 RC_TIMER_STOP(_timer_vm_op_prologue);
118 return true;
119 }
120
121 void VM_RedefineClasses::doit() {
122 Thread *thread = Thread::current();
123
124 if (UseSharedSpaces) {
125 // Sharing is enabled so we remap the shared readonly space to
126 // shared readwrite, private just in case we need to redefine
127 // a shared class. We do the remap during the doit() phase of
128 // the safepoint to be safer.
129 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
130 RC_TRACE_WITH_THREAD(0x00000001, thread,
131 ("failed to remap shared readonly space to readwrite, private"));
132 _res = JVMTI_ERROR_INTERNAL;
133 return;
134 }
135 }
136
137 // Mark methods seen on stack and everywhere else so old methods are not
138 // cleaned up if they're on the stack.
139 MetadataOnStackMark md_on_stack(true);
140 HandleMark hm(thread); // make sure any handles created are deleted
141 // before the stack walk again.
142
143 for (int i = 0; i < _class_count; i++) {
144 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
145 }
146
147 // Clean out MethodData pointing to old Method*
148 // Have to do this after all classes are redefined and all methods that
149 // are redefined are marked as old.
150 MethodDataCleaner clean_weak_method_links;
151 ClassLoaderDataGraph::classes_do(&clean_weak_method_links);
152
153 // Disable any dependent concurrent compilations
154 SystemDictionary::notice_modification();
155
156 // Set flag indicating that some invariants are no longer true.
157 // See jvmtiExport.hpp for detailed explanation.
158 JvmtiExport::set_has_redefined_a_class();
159
160 // check_class() is optionally called for product bits, but is
161 // always called for non-product bits.
162 #ifdef PRODUCT
163 if (RC_TRACE_ENABLED(0x00004000)) {
164 #endif
165 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
166 CheckClass check_class(thread);
167 ClassLoaderDataGraph::classes_do(&check_class);
168 #ifdef PRODUCT
169 }
170 #endif
171 }
172
173 void VM_RedefineClasses::doit_epilogue() {
174 // Free os::malloc allocated memory.
175 os::free(_scratch_classes);
176
177 // Reset the_class_oop to null for error printing.
178 _the_class_oop = NULL;
179
180 if (RC_TRACE_ENABLED(0x00000004)) {
181 // Used to have separate timers for "doit" and "all", but the timer
182 // overhead skewed the measurements.
183 jlong doit_time = _timer_rsc_phase1.milliseconds() +
184 _timer_rsc_phase2.milliseconds();
185 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
186
187 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
188 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
189 _timer_vm_op_prologue.milliseconds(), doit_time));
190 RC_TRACE(0x00000004,
191 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
192 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
193 }
194 }
195
196 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
197 // classes for primitives cannot be redefined
198 if (java_lang_Class::is_primitive(klass_mirror)) {
199 return false;
200 }
201 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
202 // classes for arrays cannot be redefined
203 if (the_class_oop == NULL || !the_class_oop->is_instance_klass()) {
204 return false;
205 }
206 return true;
207 }
208
209 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
210 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
211 // direct CP entries, there is just the current entry to append. For
212 // indirect and double-indirect CP entries, there are zero or more
213 // referenced CP entries along with the current entry to append.
214 // Indirect and double-indirect CP entries are handled by recursive
215 // calls to append_entry() as needed. The referenced CP entries are
216 // always appended to *merge_cp_p before the referee CP entry. These
217 // referenced CP entries may already exist in *merge_cp_p in which case
218 // there is nothing extra to append and only the current entry is
219 // appended.
220 void VM_RedefineClasses::append_entry(const constantPoolHandle& scratch_cp,
221 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
222 TRAPS) {
223
224 // append is different depending on entry tag type
225 switch (scratch_cp->tag_at(scratch_i).value()) {
226
227 // The old verifier is implemented outside the VM. It loads classes,
228 // but does not resolve constant pool entries directly so we never
229 // see Class entries here with the old verifier. Similarly the old
230 // verifier does not like Class entries in the input constant pool.
231 // The split-verifier is implemented in the VM so it can optionally
232 // and directly resolve constant pool entries to load classes. The
233 // split-verifier can accept either Class entries or UnresolvedClass
234 // entries in the input constant pool. We revert the appended copy
235 // back to UnresolvedClass so that either verifier will be happy
236 // with the constant pool entry.
237 case JVM_CONSTANT_Class:
238 {
239 // revert the copy to JVM_CONSTANT_UnresolvedClass
240 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
241 scratch_cp->klass_name_at(scratch_i));
242
243 if (scratch_i != *merge_cp_length_p) {
244 // The new entry in *merge_cp_p is at a different index than
245 // the new entry in scratch_cp so we need to map the index values.
246 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
247 }
248 (*merge_cp_length_p)++;
249 } break;
250
251 // these are direct CP entries so they can be directly appended,
252 // but double and long take two constant pool entries
253 case JVM_CONSTANT_Double: // fall through
254 case JVM_CONSTANT_Long:
255 {
256 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
257 THREAD);
258
259 if (scratch_i != *merge_cp_length_p) {
260 // The new entry in *merge_cp_p is at a different index than
261 // the new entry in scratch_cp so we need to map the index values.
262 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
263 }
264 (*merge_cp_length_p) += 2;
265 } break;
266
267 // these are direct CP entries so they can be directly appended
268 case JVM_CONSTANT_Float: // fall through
269 case JVM_CONSTANT_Integer: // fall through
270 case JVM_CONSTANT_Utf8: // fall through
271
272 // This was an indirect CP entry, but it has been changed into
273 // Symbol*s so this entry can be directly appended.
274 case JVM_CONSTANT_String: // fall through
275
276 // These were indirect CP entries, but they have been changed into
277 // Symbol*s so these entries can be directly appended.
278 case JVM_CONSTANT_UnresolvedClass: // fall through
279 {
280 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
281 THREAD);
282
283 if (scratch_i != *merge_cp_length_p) {
284 // The new entry in *merge_cp_p is at a different index than
285 // the new entry in scratch_cp so we need to map the index values.
286 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
287 }
288 (*merge_cp_length_p)++;
289 } break;
290
291 // this is an indirect CP entry so it needs special handling
292 case JVM_CONSTANT_NameAndType:
293 {
294 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
295 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
296 merge_cp_length_p, THREAD);
297
298 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
299 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
300 merge_cp_p, merge_cp_length_p,
301 THREAD);
302
303 // If the referenced entries already exist in *merge_cp_p, then
304 // both new_name_ref_i and new_signature_ref_i will both be 0.
305 // In that case, all we are appending is the current entry.
306 if (new_name_ref_i != name_ref_i) {
307 RC_TRACE(0x00080000,
308 ("NameAndType entry@%d name_ref_index change: %d to %d",
309 *merge_cp_length_p, name_ref_i, new_name_ref_i));
310 }
311 if (new_signature_ref_i != signature_ref_i) {
312 RC_TRACE(0x00080000,
313 ("NameAndType entry@%d signature_ref_index change: %d to %d",
314 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
315 }
316
317 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
318 new_name_ref_i, new_signature_ref_i);
319 if (scratch_i != *merge_cp_length_p) {
320 // The new entry in *merge_cp_p is at a different index than
321 // the new entry in scratch_cp so we need to map the index values.
322 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
323 }
324 (*merge_cp_length_p)++;
325 } break;
326
327 // this is a double-indirect CP entry so it needs special handling
328 case JVM_CONSTANT_Fieldref: // fall through
329 case JVM_CONSTANT_InterfaceMethodref: // fall through
330 case JVM_CONSTANT_Methodref:
331 {
332 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
333 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
334 merge_cp_p, merge_cp_length_p, THREAD);
335
336 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
337 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
338 merge_cp_p, merge_cp_length_p, THREAD);
339
340 const char *entry_name = NULL;
341 switch (scratch_cp->tag_at(scratch_i).value()) {
342 case JVM_CONSTANT_Fieldref:
343 entry_name = "Fieldref";
344 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
345 new_name_and_type_ref_i);
346 break;
347 case JVM_CONSTANT_InterfaceMethodref:
348 entry_name = "IFMethodref";
349 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
350 new_klass_ref_i, new_name_and_type_ref_i);
351 break;
352 case JVM_CONSTANT_Methodref:
353 entry_name = "Methodref";
354 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
355 new_name_and_type_ref_i);
356 break;
357 default:
358 guarantee(false, "bad switch");
359 break;
360 }
361
362 if (klass_ref_i != new_klass_ref_i) {
363 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
364 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
365 }
366 if (name_and_type_ref_i != new_name_and_type_ref_i) {
367 RC_TRACE(0x00080000,
368 ("%s entry@%d name_and_type_index changed: %d to %d",
369 entry_name, *merge_cp_length_p, name_and_type_ref_i,
370 new_name_and_type_ref_i));
371 }
372
373 if (scratch_i != *merge_cp_length_p) {
374 // The new entry in *merge_cp_p is at a different index than
375 // the new entry in scratch_cp so we need to map the index values.
376 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
377 }
378 (*merge_cp_length_p)++;
379 } break;
380
381 // this is an indirect CP entry so it needs special handling
382 case JVM_CONSTANT_MethodType:
383 {
384 int ref_i = scratch_cp->method_type_index_at(scratch_i);
385 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
386 merge_cp_length_p, THREAD);
387 if (new_ref_i != ref_i) {
388 RC_TRACE(0x00080000,
389 ("MethodType entry@%d ref_index change: %d to %d",
390 *merge_cp_length_p, ref_i, new_ref_i));
391 }
392 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
393 if (scratch_i != *merge_cp_length_p) {
394 // The new entry in *merge_cp_p is at a different index than
395 // the new entry in scratch_cp so we need to map the index values.
396 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
397 }
398 (*merge_cp_length_p)++;
399 } break;
400
401 // this is an indirect CP entry so it needs special handling
402 case JVM_CONSTANT_MethodHandle:
403 {
404 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
405 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
406 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
407 merge_cp_length_p, THREAD);
408 if (new_ref_i != ref_i) {
409 RC_TRACE(0x00080000,
410 ("MethodHandle entry@%d ref_index change: %d to %d",
411 *merge_cp_length_p, ref_i, new_ref_i));
412 }
413 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
414 if (scratch_i != *merge_cp_length_p) {
415 // The new entry in *merge_cp_p is at a different index than
416 // the new entry in scratch_cp so we need to map the index values.
417 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
418 }
419 (*merge_cp_length_p)++;
420 } break;
421
422 // this is an indirect CP entry so it needs special handling
423 case JVM_CONSTANT_InvokeDynamic:
424 {
425 // Index of the bootstrap specifier in the operands array
426 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
427 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
428 merge_cp_length_p, THREAD);
429 // The bootstrap method NameAndType_info index
430 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
431 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
432 merge_cp_length_p, THREAD);
433 if (new_bs_i != old_bs_i) {
434 RC_TRACE(0x00080000,
435 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
436 *merge_cp_length_p, old_bs_i, new_bs_i));
437 }
438 if (new_ref_i != old_ref_i) {
439 RC_TRACE(0x00080000,
440 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
441 *merge_cp_length_p, old_ref_i, new_ref_i));
442 }
443
444 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
445 if (scratch_i != *merge_cp_length_p) {
446 // The new entry in *merge_cp_p is at a different index than
447 // the new entry in scratch_cp so we need to map the index values.
448 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
449 }
450 (*merge_cp_length_p)++;
451 } break;
452
453 // At this stage, Class or UnresolvedClass could be here, but not
454 // ClassIndex
455 case JVM_CONSTANT_ClassIndex: // fall through
456
457 // Invalid is used as the tag for the second constant pool entry
458 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
459 // not be seen by itself.
460 case JVM_CONSTANT_Invalid: // fall through
461
462 // At this stage, String could be here, but not StringIndex
463 case JVM_CONSTANT_StringIndex: // fall through
464
465 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
466 // here
467 case JVM_CONSTANT_UnresolvedClassInError: // fall through
468
469 default:
470 {
471 // leave a breadcrumb
472 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
473 ShouldNotReachHere();
474 } break;
475 } // end switch tag value
476 } // end append_entry()
477
478
479 int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp,
480 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
481
482 int new_ref_i = ref_i;
483 bool match = (ref_i < *merge_cp_length_p) &&
484 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
485
486 if (!match) {
487 // forward reference in *merge_cp_p or not a direct match
488 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
489 if (found_i != 0) {
490 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
491 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
492 new_ref_i = found_i;
493 map_index(scratch_cp, ref_i, found_i);
494 } else {
495 // no match found so we have to append this entry to *merge_cp_p
496 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
497 // The above call to append_entry() can only append one entry
498 // so the post call query of *merge_cp_length_p is only for
499 // the sake of consistency.
500 new_ref_i = *merge_cp_length_p - 1;
501 }
502 }
503
504 return new_ref_i;
505 } // end find_or_append_indirect_entry()
506
507
508 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
509 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
510 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
511 void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i,
512 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
513
514 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
515 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
516 merge_cp_length_p, THREAD);
517 if (new_ref_i != old_ref_i) {
518 RC_TRACE(0x00080000,
519 ("operands entry@%d bootstrap method ref_index change: %d to %d",
520 _operands_cur_length, old_ref_i, new_ref_i));
521 }
522
523 Array<u2>* merge_ops = (*merge_cp_p)->operands();
524 int new_bs_i = _operands_cur_length;
525 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
526 // However, the operand_offset_at(0) was set in the extend_operands() call.
527 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
528 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
529 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
530
531 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
532 merge_ops->at_put(new_base++, new_ref_i);
533 merge_ops->at_put(new_base++, argc);
534
535 for (int i = 0; i < argc; i++) {
536 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
537 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
538 merge_cp_length_p, THREAD);
539 merge_ops->at_put(new_base++, new_arg_ref_i);
540 if (new_arg_ref_i != old_arg_ref_i) {
541 RC_TRACE(0x00080000,
542 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
543 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
544 }
545 }
546 if (old_bs_i != _operands_cur_length) {
547 // The bootstrap specifier in *merge_cp_p is at a different index than
548 // that in scratch_cp so we need to map the index values.
549 map_operand_index(old_bs_i, new_bs_i);
550 }
551 _operands_cur_length++;
552 } // end append_operand()
553
554
555 int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp,
556 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
557
558 int new_bs_i = old_bs_i; // bootstrap specifier index
559 bool match = (old_bs_i < _operands_cur_length) &&
560 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
561
562 if (!match) {
563 // forward reference in *merge_cp_p or not a direct match
564 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
565 _operands_cur_length, THREAD);
566 if (found_i != -1) {
567 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
568 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
569 new_bs_i = found_i;
570 map_operand_index(old_bs_i, found_i);
571 } else {
572 // no match found so we have to append this bootstrap specifier to *merge_cp_p
573 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
574 new_bs_i = _operands_cur_length - 1;
575 }
576 }
577 return new_bs_i;
578 } // end find_or_append_operand()
579
580
581 void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) {
582 if (merge_cp->operands() == NULL) {
583 return;
584 }
585 // Shrink the merge_cp operands
586 merge_cp->shrink_operands(_operands_cur_length, CHECK);
587
588 if (RC_TRACE_ENABLED(0x00040000)) {
589 // don't want to loop unless we are tracing
590 int count = 0;
591 for (int i = 1; i < _operands_index_map_p->length(); i++) {
592 int value = _operands_index_map_p->at(i);
593 if (value != -1) {
594 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
595 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
596 count++;
597 }
598 }
599 }
600 // Clean-up
601 _operands_index_map_p = NULL;
602 _operands_cur_length = 0;
603 _operands_index_map_count = 0;
604 } // end finalize_operands_merge()
605
606
607 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
608 instanceKlassHandle the_class,
609 instanceKlassHandle scratch_class) {
610 int i;
611
612 // Check superclasses, or rather their names, since superclasses themselves can be
613 // requested to replace.
614 // Check for NULL superclass first since this might be java.lang.Object
615 if (the_class->super() != scratch_class->super() &&
616 (the_class->super() == NULL || scratch_class->super() == NULL ||
617 the_class->super()->name() !=
618 scratch_class->super()->name())) {
619 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
620 }
621
622 // Check if the number, names and order of directly implemented interfaces are the same.
623 // I think in principle we should just check if the sets of names of directly implemented
624 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
625 // .java file, also changes in .class file) should not matter. However, comparing sets is
626 // technically a bit more difficult, and, more importantly, I am not sure at present that the
627 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
628 // rely on it somewhere.
629 Array<Klass*>* k_interfaces = the_class->local_interfaces();
630 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
631 int n_intfs = k_interfaces->length();
632 if (n_intfs != k_new_interfaces->length()) {
633 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
634 }
635 for (i = 0; i < n_intfs; i++) {
636 if (k_interfaces->at(i)->name() !=
637 k_new_interfaces->at(i)->name()) {
638 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
639 }
640 }
641
642 // Check whether class is in the error init state.
643 if (the_class->is_in_error_state()) {
644 // TBD #5057930: special error code is needed in 1.6
645 return JVMTI_ERROR_INVALID_CLASS;
646 }
647
648 // Check whether class modifiers are the same.
649 jushort old_flags = (jushort) the_class->access_flags().get_flags();
650 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
651 if (old_flags != new_flags) {
652 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
653 }
654
655 // Check if the number, names, types and order of fields declared in these classes
656 // are the same.
657 JavaFieldStream old_fs(the_class);
658 JavaFieldStream new_fs(scratch_class);
659 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
660 // access
661 old_flags = old_fs.access_flags().as_short();
662 new_flags = new_fs.access_flags().as_short();
663 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
664 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
665 }
666 // offset
667 if (old_fs.offset() != new_fs.offset()) {
668 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
669 }
670 // name and signature
671 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
672 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
673 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
674 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
675 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
676 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
677 }
678 }
679
680 // If both streams aren't done then we have a differing number of
681 // fields.
682 if (!old_fs.done() || !new_fs.done()) {
683 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
684 }
685
686 // Do a parallel walk through the old and new methods. Detect
687 // cases where they match (exist in both), have been added in
688 // the new methods, or have been deleted (exist only in the
689 // old methods). The class file parser places methods in order
690 // by method name, but does not order overloaded methods by
691 // signature. In order to determine what fate befell the methods,
692 // this code places the overloaded new methods that have matching
693 // old methods in the same order as the old methods and places
694 // new overloaded methods at the end of overloaded methods of
695 // that name. The code for this order normalization is adapted
696 // from the algorithm used in InstanceKlass::find_method().
697 // Since we are swapping out of order entries as we find them,
698 // we only have to search forward through the overloaded methods.
699 // Methods which are added and have the same name as an existing
700 // method (but different signature) will be put at the end of
701 // the methods with that name, and the name mismatch code will
702 // handle them.
703 Array<Method*>* k_old_methods(the_class->methods());
704 Array<Method*>* k_new_methods(scratch_class->methods());
705 int n_old_methods = k_old_methods->length();
706 int n_new_methods = k_new_methods->length();
707 Thread* thread = Thread::current();
708
709 int ni = 0;
710 int oi = 0;
711 while (true) {
712 Method* k_old_method;
713 Method* k_new_method;
714 enum { matched, added, deleted, undetermined } method_was = undetermined;
715
716 if (oi >= n_old_methods) {
717 if (ni >= n_new_methods) {
718 break; // we've looked at everything, done
719 }
720 // New method at the end
721 k_new_method = k_new_methods->at(ni);
722 method_was = added;
723 } else if (ni >= n_new_methods) {
724 // Old method, at the end, is deleted
725 k_old_method = k_old_methods->at(oi);
726 method_was = deleted;
727 } else {
728 // There are more methods in both the old and new lists
729 k_old_method = k_old_methods->at(oi);
730 k_new_method = k_new_methods->at(ni);
731 if (k_old_method->name() != k_new_method->name()) {
732 // Methods are sorted by method name, so a mismatch means added
733 // or deleted
734 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
735 method_was = added;
736 } else {
737 method_was = deleted;
738 }
739 } else if (k_old_method->signature() == k_new_method->signature()) {
740 // Both the name and signature match
741 method_was = matched;
742 } else {
743 // The name matches, but the signature doesn't, which means we have to
744 // search forward through the new overloaded methods.
745 int nj; // outside the loop for post-loop check
746 for (nj = ni + 1; nj < n_new_methods; nj++) {
747 Method* m = k_new_methods->at(nj);
748 if (k_old_method->name() != m->name()) {
749 // reached another method name so no more overloaded methods
750 method_was = deleted;
751 break;
752 }
753 if (k_old_method->signature() == m->signature()) {
754 // found a match so swap the methods
755 k_new_methods->at_put(ni, m);
756 k_new_methods->at_put(nj, k_new_method);
757 k_new_method = m;
758 method_was = matched;
759 break;
760 }
761 }
762
763 if (nj >= n_new_methods) {
764 // reached the end without a match; so method was deleted
765 method_was = deleted;
766 }
767 }
768 }
769
770 switch (method_was) {
771 case matched:
772 // methods match, be sure modifiers do too
773 old_flags = (jushort) k_old_method->access_flags().get_flags();
774 new_flags = (jushort) k_new_method->access_flags().get_flags();
775 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
776 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
777 }
778 {
779 u2 new_num = k_new_method->method_idnum();
780 u2 old_num = k_old_method->method_idnum();
781 if (new_num != old_num) {
782 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
783 if (idnum_owner != NULL) {
784 // There is already a method assigned this idnum -- switch them
785 // Take current and original idnum from the new_method
786 idnum_owner->set_method_idnum(new_num);
787 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
788 }
789 // Take current and original idnum from the old_method
790 k_new_method->set_method_idnum(old_num);
791 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
792 if (thread->has_pending_exception()) {
793 return JVMTI_ERROR_OUT_OF_MEMORY;
794 }
795 }
796 }
797 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
798 k_new_method->name_and_sig_as_C_string(), ni,
799 k_old_method->name_and_sig_as_C_string(), oi));
800 // advance to next pair of methods
801 ++oi;
802 ++ni;
803 break;
804 case added:
805 // method added, see if it is OK
806 new_flags = (jushort) k_new_method->access_flags().get_flags();
807 if ((new_flags & JVM_ACC_PRIVATE) == 0
808 // hack: private should be treated as final, but alas
809 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
810 ) {
811 // new methods must be private
812 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
813 }
814 {
815 u2 num = the_class->next_method_idnum();
816 if (num == ConstMethod::UNSET_IDNUM) {
817 // cannot add any more methods
818 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
819 }
820 u2 new_num = k_new_method->method_idnum();
821 Method* idnum_owner = scratch_class->method_with_idnum(num);
822 if (idnum_owner != NULL) {
823 // There is already a method assigned this idnum -- switch them
824 // Take current and original idnum from the new_method
825 idnum_owner->set_method_idnum(new_num);
826 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
827 }
828 k_new_method->set_method_idnum(num);
829 k_new_method->set_orig_method_idnum(num);
830 if (thread->has_pending_exception()) {
831 return JVMTI_ERROR_OUT_OF_MEMORY;
832 }
833 }
834 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
835 k_new_method->name_and_sig_as_C_string(), ni));
836 ++ni; // advance to next new method
837 break;
838 case deleted:
839 // method deleted, see if it is OK
840 old_flags = (jushort) k_old_method->access_flags().get_flags();
841 if ((old_flags & JVM_ACC_PRIVATE) == 0
842 // hack: private should be treated as final, but alas
843 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
844 ) {
845 // deleted methods must be private
846 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
847 }
848 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
849 k_old_method->name_and_sig_as_C_string(), oi));
850 ++oi; // advance to next old method
851 break;
852 default:
853 ShouldNotReachHere();
854 }
855 }
856
857 return JVMTI_ERROR_NONE;
858 }
859
860
861 // Find new constant pool index value for old constant pool index value
862 // by seaching the index map. Returns zero (0) if there is no mapped
863 // value for the old constant pool index.
864 int VM_RedefineClasses::find_new_index(int old_index) {
865 if (_index_map_count == 0) {
866 // map is empty so nothing can be found
867 return 0;
868 }
869
870 if (old_index < 1 || old_index >= _index_map_p->length()) {
871 // The old_index is out of range so it is not mapped. This should
872 // not happen in regular constant pool merging use, but it can
873 // happen if a corrupt annotation is processed.
874 return 0;
875 }
876
877 int value = _index_map_p->at(old_index);
878 if (value == -1) {
879 // the old_index is not mapped
880 return 0;
881 }
882
883 return value;
884 } // end find_new_index()
885
886
887 // Find new bootstrap specifier index value for old bootstrap specifier index
888 // value by seaching the index map. Returns unused index (-1) if there is
889 // no mapped value for the old bootstrap specifier index.
890 int VM_RedefineClasses::find_new_operand_index(int old_index) {
891 if (_operands_index_map_count == 0) {
892 // map is empty so nothing can be found
893 return -1;
894 }
895
896 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
897 // The old_index is out of range so it is not mapped.
898 // This should not happen in regular constant pool merging use.
899 return -1;
900 }
901
902 int value = _operands_index_map_p->at(old_index);
903 if (value == -1) {
904 // the old_index is not mapped
905 return -1;
906 }
907
908 return value;
909 } // end find_new_operand_index()
910
911
912 // Returns true if the current mismatch is due to a resolved/unresolved
913 // class pair. Otherwise, returns false.
914 bool VM_RedefineClasses::is_unresolved_class_mismatch(const constantPoolHandle& cp1,
915 int index1, const constantPoolHandle& cp2, int index2) {
916
917 jbyte t1 = cp1->tag_at(index1).value();
918 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
919 return false; // wrong entry type; not our special case
920 }
921
922 jbyte t2 = cp2->tag_at(index2).value();
923 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
924 return false; // wrong entry type; not our special case
925 }
926
927 if (t1 == t2) {
928 return false; // not a mismatch; not our special case
929 }
930
931 char *s1 = cp1->klass_name_at(index1)->as_C_string();
932 char *s2 = cp2->klass_name_at(index2)->as_C_string();
933 if (strcmp(s1, s2) != 0) {
934 return false; // strings don't match; not our special case
935 }
936
937 return true; // made it through the gauntlet; this is our special case
938 } // end is_unresolved_class_mismatch()
939
940
941 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
942
943 // For consistency allocate memory using os::malloc wrapper.
944 _scratch_classes = (Klass**)
945 os::malloc(sizeof(Klass*) * _class_count, mtClass);
946 if (_scratch_classes == NULL) {
947 return JVMTI_ERROR_OUT_OF_MEMORY;
948 }
949 // Zero initialize the _scratch_classes array.
950 for (int i = 0; i < _class_count; i++) {
951 _scratch_classes[i] = NULL;
952 }
953
954 ResourceMark rm(THREAD);
955
956 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
957 // state can only be NULL if the current thread is exiting which
958 // should not happen since we're trying to do a RedefineClasses
959 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
960 for (int i = 0; i < _class_count; i++) {
961 // Create HandleMark so that any handles created while loading new class
962 // versions are deleted. Constant pools are deallocated while merging
963 // constant pools
964 HandleMark hm(THREAD);
965
966 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
967 // classes for primitives cannot be redefined
968 if (!is_modifiable_class(mirror)) {
969 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
970 }
971 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
972 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
973 Symbol* the_class_sym = the_class->name();
974
975 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
976 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
977 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
978 the_class->external_name(), _class_load_kind,
979 os::available_memory() >> 10));
980
981 ClassFileStream st((u1*)_class_defs[i].class_bytes,
982 _class_defs[i].class_byte_count,
983 "__VM_RedefineClasses__",
984 ClassFileStream::verify);
985
986 // Parse the stream.
987 Handle the_class_loader(THREAD, the_class->class_loader());
988 Handle protection_domain(THREAD, the_class->protection_domain());
989 // Set redefined class handle in JvmtiThreadState class.
990 // This redefined class is sent to agent event handler for class file
991 // load hook event.
992 state->set_class_being_redefined(&the_class, _class_load_kind);
993
994 Klass* k = SystemDictionary::parse_stream(the_class_sym,
995 the_class_loader,
996 protection_domain,
997 &st,
998 THREAD);
999 // Clear class_being_redefined just to be sure.
1000 state->clear_class_being_redefined();
1001
1002 // TODO: if this is retransform, and nothing changed we can skip it
1003
1004 instanceKlassHandle scratch_class (THREAD, k);
1005
1006 // Need to clean up allocated InstanceKlass if there's an error so assign
1007 // the result here. Caller deallocates all the scratch classes in case of
1008 // an error.
1009 _scratch_classes[i] = k;
1010
1011 if (HAS_PENDING_EXCEPTION) {
1012 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1013 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1014 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1015 ex_name->as_C_string()));
1016 CLEAR_PENDING_EXCEPTION;
1017
1018 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1019 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1020 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1021 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1022 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1023 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1024 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1025 // The message will be "XXX (wrong name: YYY)"
1026 return JVMTI_ERROR_NAMES_DONT_MATCH;
1027 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1028 return JVMTI_ERROR_OUT_OF_MEMORY;
1029 } else { // Just in case more exceptions can be thrown..
1030 return JVMTI_ERROR_FAILS_VERIFICATION;
1031 }
1032 }
1033
1034 // Ensure class is linked before redefine
1035 if (!the_class->is_linked()) {
1036 the_class->link_class(THREAD);
1037 if (HAS_PENDING_EXCEPTION) {
1038 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1039 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1040 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1041 ex_name->as_C_string()));
1042 CLEAR_PENDING_EXCEPTION;
1043 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1044 return JVMTI_ERROR_OUT_OF_MEMORY;
1045 } else {
1046 return JVMTI_ERROR_INTERNAL;
1047 }
1048 }
1049 }
1050
1051 // Do the validity checks in compare_and_normalize_class_versions()
1052 // before verifying the byte codes. By doing these checks first, we
1053 // limit the number of functions that require redirection from
1054 // the_class to scratch_class. In particular, we don't have to
1055 // modify JNI GetSuperclass() and thus won't change its performance.
1056 jvmtiError res = compare_and_normalize_class_versions(the_class,
1057 scratch_class);
1058 if (res != JVMTI_ERROR_NONE) {
1059 return res;
1060 }
1061
1062 // verify what the caller passed us
1063 {
1064 // The bug 6214132 caused the verification to fail.
1065 // Information about the_class and scratch_class is temporarily
1066 // recorded into jvmtiThreadState. This data is used to redirect
1067 // the_class to scratch_class in the JVM_* functions called by the
1068 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1069 // description.
1070 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1071 Verifier::verify(
1072 scratch_class, Verifier::ThrowException, true, THREAD);
1073 }
1074
1075 if (HAS_PENDING_EXCEPTION) {
1076 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1077 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1078 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1079 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1080 CLEAR_PENDING_EXCEPTION;
1081 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1082 return JVMTI_ERROR_OUT_OF_MEMORY;
1083 } else {
1084 // tell the caller the bytecodes are bad
1085 return JVMTI_ERROR_FAILS_VERIFICATION;
1086 }
1087 }
1088
1089 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1090 if (HAS_PENDING_EXCEPTION) {
1091 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1092 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1093 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1094 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1095 CLEAR_PENDING_EXCEPTION;
1096 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1097 return JVMTI_ERROR_OUT_OF_MEMORY;
1098 } else {
1099 return JVMTI_ERROR_INTERNAL;
1100 }
1101 }
1102
1103 if (VerifyMergedCPBytecodes) {
1104 // verify what we have done during constant pool merging
1105 {
1106 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1107 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1108 }
1109
1110 if (HAS_PENDING_EXCEPTION) {
1111 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1112 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1113 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1114 ("verify_byte_codes post merge-CP exception: '%s'",
1115 ex_name->as_C_string()));
1116 CLEAR_PENDING_EXCEPTION;
1117 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1118 return JVMTI_ERROR_OUT_OF_MEMORY;
1119 } else {
1120 // tell the caller that constant pool merging screwed up
1121 return JVMTI_ERROR_INTERNAL;
1122 }
1123 }
1124 }
1125
1126 Rewriter::rewrite(scratch_class, THREAD);
1127 if (!HAS_PENDING_EXCEPTION) {
1128 scratch_class->link_methods(THREAD);
1129 }
1130 if (HAS_PENDING_EXCEPTION) {
1131 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1132 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1133 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1134 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1135 CLEAR_PENDING_EXCEPTION;
1136 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1137 return JVMTI_ERROR_OUT_OF_MEMORY;
1138 } else {
1139 return JVMTI_ERROR_INTERNAL;
1140 }
1141 }
1142
1143 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1144 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1145 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1146 the_class->external_name(), os::available_memory() >> 10));
1147 }
1148
1149 return JVMTI_ERROR_NONE;
1150 }
1151
1152
1153 // Map old_index to new_index as needed. scratch_cp is only needed
1154 // for RC_TRACE() calls.
1155 void VM_RedefineClasses::map_index(const constantPoolHandle& scratch_cp,
1156 int old_index, int new_index) {
1157 if (find_new_index(old_index) != 0) {
1158 // old_index is already mapped
1159 return;
1160 }
1161
1162 if (old_index == new_index) {
1163 // no mapping is needed
1164 return;
1165 }
1166
1167 _index_map_p->at_put(old_index, new_index);
1168 _index_map_count++;
1169
1170 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1171 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1172 } // end map_index()
1173
1174
1175 // Map old_index to new_index as needed.
1176 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1177 if (find_new_operand_index(old_index) != -1) {
1178 // old_index is already mapped
1179 return;
1180 }
1181
1182 if (old_index == new_index) {
1183 // no mapping is needed
1184 return;
1185 }
1186
1187 _operands_index_map_p->at_put(old_index, new_index);
1188 _operands_index_map_count++;
1189
1190 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1191 } // end map_index()
1192
1193
1194 // Merge old_cp and scratch_cp and return the results of the merge via
1195 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1196 // merge_cp_length_p. The entries in old_cp occupy the same locations
1197 // in *merge_cp_p. Also creates a map of indices from entries in
1198 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1199 // entries are only created for entries in scratch_cp that occupy a
1200 // different location in *merged_cp_p.
1201 bool VM_RedefineClasses::merge_constant_pools(const constantPoolHandle& old_cp,
1202 const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p,
1203 int *merge_cp_length_p, TRAPS) {
1204
1205 if (merge_cp_p == NULL) {
1206 assert(false, "caller must provide scratch constantPool");
1207 return false; // robustness
1208 }
1209 if (merge_cp_length_p == NULL) {
1210 assert(false, "caller must provide scratch CP length");
1211 return false; // robustness
1212 }
1213 // Worst case we need old_cp->length() + scratch_cp()->length(),
1214 // but the caller might be smart so make sure we have at least
1215 // the minimum.
1216 if ((*merge_cp_p)->length() < old_cp->length()) {
1217 assert(false, "merge area too small");
1218 return false; // robustness
1219 }
1220
1221 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1222 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1223 scratch_cp->length()));
1224
1225 {
1226 // Pass 0:
1227 // The old_cp is copied to *merge_cp_p; this means that any code
1228 // using old_cp does not have to change. This work looks like a
1229 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1230 // handle one special case:
1231 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1232 // This will make verification happy.
1233
1234 int old_i; // index into old_cp
1235
1236 // index zero (0) is not used in constantPools
1237 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1238 // leave debugging crumb
1239 jbyte old_tag = old_cp->tag_at(old_i).value();
1240 switch (old_tag) {
1241 case JVM_CONSTANT_Class:
1242 case JVM_CONSTANT_UnresolvedClass:
1243 // revert the copy to JVM_CONSTANT_UnresolvedClass
1244 // May be resolving while calling this so do the same for
1245 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1246 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1247 old_cp->klass_name_at(old_i));
1248 break;
1249
1250 case JVM_CONSTANT_Double:
1251 case JVM_CONSTANT_Long:
1252 // just copy the entry to *merge_cp_p, but double and long take
1253 // two constant pool entries
1254 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1255 old_i++;
1256 break;
1257
1258 default:
1259 // just copy the entry to *merge_cp_p
1260 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1261 break;
1262 }
1263 } // end for each old_cp entry
1264
1265 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1266 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1267
1268 // We don't need to sanity check that *merge_cp_length_p is within
1269 // *merge_cp_p bounds since we have the minimum on-entry check above.
1270 (*merge_cp_length_p) = old_i;
1271 }
1272
1273 // merge_cp_len should be the same as old_cp->length() at this point
1274 // so this trace message is really a "warm-and-breathing" message.
1275 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1276 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1277
1278 int scratch_i; // index into scratch_cp
1279 {
1280 // Pass 1a:
1281 // Compare scratch_cp entries to the old_cp entries that we have
1282 // already copied to *merge_cp_p. In this pass, we are eliminating
1283 // exact duplicates (matching entry at same index) so we only
1284 // compare entries in the common indice range.
1285 int increment = 1;
1286 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1287 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1288 switch (scratch_cp->tag_at(scratch_i).value()) {
1289 case JVM_CONSTANT_Double:
1290 case JVM_CONSTANT_Long:
1291 // double and long take two constant pool entries
1292 increment = 2;
1293 break;
1294
1295 default:
1296 increment = 1;
1297 break;
1298 }
1299
1300 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1301 scratch_i, CHECK_0);
1302 if (match) {
1303 // found a match at the same index so nothing more to do
1304 continue;
1305 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1306 *merge_cp_p, scratch_i)) {
1307 // The mismatch in compare_entry_to() above is because of a
1308 // resolved versus unresolved class entry at the same index
1309 // with the same string value. Since Pass 0 reverted any
1310 // class entries to unresolved class entries in *merge_cp_p,
1311 // we go with the unresolved class entry.
1312 continue;
1313 }
1314
1315 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1316 CHECK_0);
1317 if (found_i != 0) {
1318 guarantee(found_i != scratch_i,
1319 "compare_entry_to() and find_matching_entry() do not agree");
1320
1321 // Found a matching entry somewhere else in *merge_cp_p so
1322 // just need a mapping entry.
1323 map_index(scratch_cp, scratch_i, found_i);
1324 continue;
1325 }
1326
1327 // The find_matching_entry() call above could fail to find a match
1328 // due to a resolved versus unresolved class or string entry situation
1329 // like we solved above with the is_unresolved_*_mismatch() calls.
1330 // However, we would have to call is_unresolved_*_mismatch() over
1331 // all of *merge_cp_p (potentially) and that doesn't seem to be
1332 // worth the time.
1333
1334 // No match found so we have to append this entry and any unique
1335 // referenced entries to *merge_cp_p.
1336 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1337 CHECK_0);
1338 }
1339 }
1340
1341 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1342 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1343 *merge_cp_length_p, scratch_i, _index_map_count));
1344
1345 if (scratch_i < scratch_cp->length()) {
1346 // Pass 1b:
1347 // old_cp is smaller than scratch_cp so there are entries in
1348 // scratch_cp that we have not yet processed. We take care of
1349 // those now.
1350 int increment = 1;
1351 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1352 switch (scratch_cp->tag_at(scratch_i).value()) {
1353 case JVM_CONSTANT_Double:
1354 case JVM_CONSTANT_Long:
1355 // double and long take two constant pool entries
1356 increment = 2;
1357 break;
1358
1359 default:
1360 increment = 1;
1361 break;
1362 }
1363
1364 int found_i =
1365 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1366 if (found_i != 0) {
1367 // Found a matching entry somewhere else in *merge_cp_p so
1368 // just need a mapping entry.
1369 map_index(scratch_cp, scratch_i, found_i);
1370 continue;
1371 }
1372
1373 // No match found so we have to append this entry and any unique
1374 // referenced entries to *merge_cp_p.
1375 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1376 CHECK_0);
1377 }
1378
1379 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1380 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1381 *merge_cp_length_p, scratch_i, _index_map_count));
1382 }
1383 finalize_operands_merge(*merge_cp_p, THREAD);
1384
1385 return true;
1386 } // end merge_constant_pools()
1387
1388
1389 // Scoped object to clean up the constant pool(s) created for merging
1390 class MergeCPCleaner {
1391 ClassLoaderData* _loader_data;
1392 ConstantPool* _cp;
1393 ConstantPool* _scratch_cp;
1394 public:
1395 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1396 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1397 ~MergeCPCleaner() {
1398 _loader_data->add_to_deallocate_list(_cp);
1399 if (_scratch_cp != NULL) {
1400 _loader_data->add_to_deallocate_list(_scratch_cp);
1401 }
1402 }
1403 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1404 };
1405
1406 // Merge constant pools between the_class and scratch_class and
1407 // potentially rewrite bytecodes in scratch_class to use the merged
1408 // constant pool.
1409 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1410 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1411 TRAPS) {
1412 // worst case merged constant pool length is old and new combined
1413 int merge_cp_length = the_class->constants()->length()
1414 + scratch_class->constants()->length();
1415
1416 // Constant pools are not easily reused so we allocate a new one
1417 // each time.
1418 // merge_cp is created unsafe for concurrent GC processing. It
1419 // should be marked safe before discarding it. Even though
1420 // garbage, if it crosses a card boundary, it may be scanned
1421 // in order to find the start of the first complete object on the card.
1422 ClassLoaderData* loader_data = the_class->class_loader_data();
1423 ConstantPool* merge_cp_oop =
1424 ConstantPool::allocate(loader_data,
1425 merge_cp_length,
1426 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1427 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1428
1429 HandleMark hm(THREAD); // make sure handles are cleared before
1430 // MergeCPCleaner clears out merge_cp_oop
1431 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1432
1433 // Get constants() from the old class because it could have been rewritten
1434 // while we were at a safepoint allocating a new constant pool.
1435 constantPoolHandle old_cp(THREAD, the_class->constants());
1436 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1437
1438 // If the length changed, the class was redefined out from under us. Return
1439 // an error.
1440 if (merge_cp_length != the_class->constants()->length()
1441 + scratch_class->constants()->length()) {
1442 return JVMTI_ERROR_INTERNAL;
1443 }
1444
1445 // Update the version number of the constant pool
1446 merge_cp->increment_and_save_version(old_cp->version());
1447
1448 ResourceMark rm(THREAD);
1449 _index_map_count = 0;
1450 _index_map_p = new intArray(scratch_cp->length(), -1);
1451
1452 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1453 _operands_index_map_count = 0;
1454 _operands_index_map_p = new intArray(
1455 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1456
1457 // reference to the cp holder is needed for copy_operands()
1458 merge_cp->set_pool_holder(scratch_class());
1459 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1460 &merge_cp_length, THREAD);
1461 merge_cp->set_pool_holder(NULL);
1462
1463 if (!result) {
1464 // The merge can fail due to memory allocation failure or due
1465 // to robustness checks.
1466 return JVMTI_ERROR_INTERNAL;
1467 }
1468
1469 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1470 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1471
1472 if (_index_map_count == 0) {
1473 // there is nothing to map between the new and merged constant pools
1474
1475 if (old_cp->length() == scratch_cp->length()) {
1476 // The old and new constant pools are the same length and the
1477 // index map is empty. This means that the three constant pools
1478 // are equivalent (but not the same). Unfortunately, the new
1479 // constant pool has not gone through link resolution nor have
1480 // the new class bytecodes gone through constant pool cache
1481 // rewriting so we can't use the old constant pool with the new
1482 // class.
1483
1484 // toss the merged constant pool at return
1485 } else if (old_cp->length() < scratch_cp->length()) {
1486 // The old constant pool has fewer entries than the new constant
1487 // pool and the index map is empty. This means the new constant
1488 // pool is a superset of the old constant pool. However, the old
1489 // class bytecodes have already gone through constant pool cache
1490 // rewriting so we can't use the new constant pool with the old
1491 // class.
1492
1493 // toss the merged constant pool at return
1494 } else {
1495 // The old constant pool has more entries than the new constant
1496 // pool and the index map is empty. This means that both the old
1497 // and merged constant pools are supersets of the new constant
1498 // pool.
1499
1500 // Replace the new constant pool with a shrunken copy of the
1501 // merged constant pool
1502 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1503 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1504 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1505 // It can't be cleaned up while there are handles to it.
1506 cp_cleaner.add_scratch_cp(scratch_cp());
1507 }
1508 } else {
1509 if (RC_TRACE_ENABLED(0x00040000)) {
1510 // don't want to loop unless we are tracing
1511 int count = 0;
1512 for (int i = 1; i < _index_map_p->length(); i++) {
1513 int value = _index_map_p->at(i);
1514
1515 if (value != -1) {
1516 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1517 ("index_map[%d]: old=%d new=%d", count, i, value));
1518 count++;
1519 }
1520 }
1521 }
1522
1523 // We have entries mapped between the new and merged constant pools
1524 // so we have to rewrite some constant pool references.
1525 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1526 return JVMTI_ERROR_INTERNAL;
1527 }
1528
1529 // Replace the new constant pool with a shrunken copy of the
1530 // merged constant pool so now the rewritten bytecodes have
1531 // valid references; the previous new constant pool will get
1532 // GCed.
1533 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1534 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1535 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1536 // It can't be cleaned up while there are handles to it.
1537 cp_cleaner.add_scratch_cp(scratch_cp());
1538 }
1539
1540 return JVMTI_ERROR_NONE;
1541 } // end merge_cp_and_rewrite()
1542
1543
1544 // Rewrite constant pool references in klass scratch_class.
1545 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1546 TRAPS) {
1547
1548 // rewrite constant pool references in the methods:
1549 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1550 // propagate failure back to caller
1551 return false;
1552 }
1553
1554 // rewrite constant pool references in the class_annotations:
1555 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1556 // propagate failure back to caller
1557 return false;
1558 }
1559
1560 // rewrite constant pool references in the fields_annotations:
1561 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1562 // propagate failure back to caller
1563 return false;
1564 }
1565
1566 // rewrite constant pool references in the methods_annotations:
1567 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1568 // propagate failure back to caller
1569 return false;
1570 }
1571
1572 // rewrite constant pool references in the methods_parameter_annotations:
1573 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1574 THREAD)) {
1575 // propagate failure back to caller
1576 return false;
1577 }
1578
1579 // rewrite constant pool references in the methods_default_annotations:
1580 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1581 THREAD)) {
1582 // propagate failure back to caller
1583 return false;
1584 }
1585
1586 // rewrite constant pool references in the class_type_annotations:
1587 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1588 // propagate failure back to caller
1589 return false;
1590 }
1591
1592 // rewrite constant pool references in the fields_type_annotations:
1593 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1594 // propagate failure back to caller
1595 return false;
1596 }
1597
1598 // rewrite constant pool references in the methods_type_annotations:
1599 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1600 // propagate failure back to caller
1601 return false;
1602 }
1603
1604 // There can be type annotations in the Code part of a method_info attribute.
1605 // These annotations are not accessible, even by reflection.
1606 // Currently they are not even parsed by the ClassFileParser.
1607 // If runtime access is added they will also need to be rewritten.
1608
1609 // rewrite source file name index:
1610 u2 source_file_name_idx = scratch_class->source_file_name_index();
1611 if (source_file_name_idx != 0) {
1612 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1613 if (new_source_file_name_idx != 0) {
1614 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1615 }
1616 }
1617
1618 // rewrite class generic signature index:
1619 u2 generic_signature_index = scratch_class->generic_signature_index();
1620 if (generic_signature_index != 0) {
1621 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1622 if (new_generic_signature_index != 0) {
1623 scratch_class->set_generic_signature_index(new_generic_signature_index);
1624 }
1625 }
1626
1627 return true;
1628 } // end rewrite_cp_refs()
1629
1630 // Rewrite constant pool references in the methods.
1631 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1632 instanceKlassHandle scratch_class, TRAPS) {
1633
1634 Array<Method*>* methods = scratch_class->methods();
1635
1636 if (methods == NULL || methods->length() == 0) {
1637 // no methods so nothing to do
1638 return true;
1639 }
1640
1641 // rewrite constant pool references in the methods:
1642 for (int i = methods->length() - 1; i >= 0; i--) {
1643 methodHandle method(THREAD, methods->at(i));
1644 methodHandle new_method;
1645 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1646 if (!new_method.is_null()) {
1647 // the method has been replaced so save the new method version
1648 // even in the case of an exception. original method is on the
1649 // deallocation list.
1650 methods->at_put(i, new_method());
1651 }
1652 if (HAS_PENDING_EXCEPTION) {
1653 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1654 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1655 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1656 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1657 // Need to clear pending exception here as the super caller sets
1658 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1659 CLEAR_PENDING_EXCEPTION;
1660 return false;
1661 }
1662 }
1663
1664 return true;
1665 }
1666
1667
1668 // Rewrite constant pool references in the specific method. This code
1669 // was adapted from Rewriter::rewrite_method().
1670 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1671 methodHandle *new_method_p, TRAPS) {
1672
1673 *new_method_p = methodHandle(); // default is no new method
1674
1675 // We cache a pointer to the bytecodes here in code_base. If GC
1676 // moves the Method*, then the bytecodes will also move which
1677 // will likely cause a crash. We create a NoSafepointVerifier
1678 // object to detect whether we pass a possible safepoint in this
1679 // code block.
1680 NoSafepointVerifier nsv;
1681
1682 // Bytecodes and their length
1683 address code_base = method->code_base();
1684 int code_length = method->code_size();
1685
1686 int bc_length;
1687 for (int bci = 0; bci < code_length; bci += bc_length) {
1688 address bcp = code_base + bci;
1689 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1690
1691 bc_length = Bytecodes::length_for(c);
1692 if (bc_length == 0) {
1693 // More complicated bytecodes report a length of zero so
1694 // we have to try again a slightly different way.
1695 bc_length = Bytecodes::length_at(method(), bcp);
1696 }
1697
1698 assert(bc_length != 0, "impossible bytecode length");
1699
1700 switch (c) {
1701 case Bytecodes::_ldc:
1702 {
1703 int cp_index = *(bcp + 1);
1704 int new_index = find_new_index(cp_index);
1705
1706 if (StressLdcRewrite && new_index == 0) {
1707 // If we are stressing ldc -> ldc_w rewriting, then we
1708 // always need a new_index value.
1709 new_index = cp_index;
1710 }
1711 if (new_index != 0) {
1712 // the original index is mapped so we have more work to do
1713 if (!StressLdcRewrite && new_index <= max_jubyte) {
1714 // The new value can still use ldc instead of ldc_w
1715 // unless we are trying to stress ldc -> ldc_w rewriting
1716 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1717 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1718 p2i(bcp), cp_index, new_index));
1719 *(bcp + 1) = new_index;
1720 } else {
1721 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1722 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1723 Bytecodes::name(c), p2i(bcp), cp_index, new_index));
1724 // the new value needs ldc_w instead of ldc
1725 u_char inst_buffer[4]; // max instruction size is 4 bytes
1726 bcp = (address)inst_buffer;
1727 // construct new instruction sequence
1728 *bcp = Bytecodes::_ldc_w;
1729 bcp++;
1730 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1731 // See comment below for difference between put_Java_u2()
1732 // and put_native_u2().
1733 Bytes::put_Java_u2(bcp, new_index);
1734
1735 Relocator rc(method, NULL /* no RelocatorListener needed */);
1736 methodHandle m;
1737 {
1738 PauseNoSafepointVerifier pnsv(&nsv);
1739
1740 // ldc is 2 bytes and ldc_w is 3 bytes
1741 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1742 }
1743
1744 // return the new method so that the caller can update
1745 // the containing class
1746 *new_method_p = method = m;
1747 // switch our bytecode processing loop from the old method
1748 // to the new method
1749 code_base = method->code_base();
1750 code_length = method->code_size();
1751 bcp = code_base + bci;
1752 c = (Bytecodes::Code)(*bcp);
1753 bc_length = Bytecodes::length_for(c);
1754 assert(bc_length != 0, "sanity check");
1755 } // end we need ldc_w instead of ldc
1756 } // end if there is a mapped index
1757 } break;
1758
1759 // these bytecodes have a two-byte constant pool index
1760 case Bytecodes::_anewarray : // fall through
1761 case Bytecodes::_checkcast : // fall through
1762 case Bytecodes::_getfield : // fall through
1763 case Bytecodes::_getstatic : // fall through
1764 case Bytecodes::_instanceof : // fall through
1765 case Bytecodes::_invokedynamic : // fall through
1766 case Bytecodes::_invokeinterface: // fall through
1767 case Bytecodes::_invokespecial : // fall through
1768 case Bytecodes::_invokestatic : // fall through
1769 case Bytecodes::_invokevirtual : // fall through
1770 case Bytecodes::_ldc_w : // fall through
1771 case Bytecodes::_ldc2_w : // fall through
1772 case Bytecodes::_multianewarray : // fall through
1773 case Bytecodes::_new : // fall through
1774 case Bytecodes::_putfield : // fall through
1775 case Bytecodes::_putstatic :
1776 {
1777 address p = bcp + 1;
1778 int cp_index = Bytes::get_Java_u2(p);
1779 int new_index = find_new_index(cp_index);
1780 if (new_index != 0) {
1781 // the original index is mapped so update w/ new value
1782 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1783 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1784 p2i(bcp), cp_index, new_index));
1785 // Rewriter::rewrite_method() uses put_native_u2() in this
1786 // situation because it is reusing the constant pool index
1787 // location for a native index into the ConstantPoolCache.
1788 // Since we are updating the constant pool index prior to
1789 // verification and ConstantPoolCache initialization, we
1790 // need to keep the new index in Java byte order.
1791 Bytes::put_Java_u2(p, new_index);
1792 }
1793 } break;
1794 }
1795 } // end for each bytecode
1796
1797 // We also need to rewrite the parameter name indexes, if there is
1798 // method parameter data present
1799 if(method->has_method_parameters()) {
1800 const int len = method->method_parameters_length();
1801 MethodParametersElement* elem = method->method_parameters_start();
1802
1803 for (int i = 0; i < len; i++) {
1804 const u2 cp_index = elem[i].name_cp_index;
1805 const u2 new_cp_index = find_new_index(cp_index);
1806 if (new_cp_index != 0) {
1807 elem[i].name_cp_index = new_cp_index;
1808 }
1809 }
1810 }
1811 } // end rewrite_cp_refs_in_method()
1812
1813
1814 // Rewrite constant pool references in the class_annotations field.
1815 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1816 instanceKlassHandle scratch_class, TRAPS) {
1817
1818 AnnotationArray* class_annotations = scratch_class->class_annotations();
1819 if (class_annotations == NULL || class_annotations->length() == 0) {
1820 // no class_annotations so nothing to do
1821 return true;
1822 }
1823
1824 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1825 ("class_annotations length=%d", class_annotations->length()));
1826
1827 int byte_i = 0; // byte index into class_annotations
1828 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1829 THREAD);
1830 }
1831
1832
1833 // Rewrite constant pool references in an annotations typeArray. This
1834 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1835 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1836 //
1837 // annotations_typeArray {
1838 // u2 num_annotations;
1839 // annotation annotations[num_annotations];
1840 // }
1841 //
1842 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1843 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1844
1845 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1846 // not enough room for num_annotations field
1847 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1848 ("length() is too small for num_annotations field"));
1849 return false;
1850 }
1851
1852 u2 num_annotations = Bytes::get_Java_u2((address)
1853 annotations_typeArray->adr_at(byte_i_ref));
1854 byte_i_ref += 2;
1855
1856 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1857 ("num_annotations=%d", num_annotations));
1858
1859 int calc_num_annotations = 0;
1860 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1861 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1862 byte_i_ref, THREAD)) {
1863 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1864 ("bad annotation_struct at %d", calc_num_annotations));
1865 // propagate failure back to caller
1866 return false;
1867 }
1868 }
1869 assert(num_annotations == calc_num_annotations, "sanity check");
1870
1871 return true;
1872 } // end rewrite_cp_refs_in_annotations_typeArray()
1873
1874
1875 // Rewrite constant pool references in the annotation struct portion of
1876 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1877 // the 2nd-edition of the VM spec:
1878 //
1879 // struct annotation {
1880 // u2 type_index;
1881 // u2 num_element_value_pairs;
1882 // {
1883 // u2 element_name_index;
1884 // element_value value;
1885 // } element_value_pairs[num_element_value_pairs];
1886 // }
1887 //
1888 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1889 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1890 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1891 // not enough room for smallest annotation_struct
1892 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1893 ("length() is too small for annotation_struct"));
1894 return false;
1895 }
1896
1897 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1898 byte_i_ref, "type_index", THREAD);
1899
1900 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1901 annotations_typeArray->adr_at(byte_i_ref));
1902 byte_i_ref += 2;
1903
1904 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1905 ("type_index=%d num_element_value_pairs=%d", type_index,
1906 num_element_value_pairs));
1907
1908 int calc_num_element_value_pairs = 0;
1909 for (; calc_num_element_value_pairs < num_element_value_pairs;
1910 calc_num_element_value_pairs++) {
1911 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1912 // not enough room for another element_name_index, let alone
1913 // the rest of another component
1914 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1915 ("length() is too small for element_name_index"));
1916 return false;
1917 }
1918
1919 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1920 annotations_typeArray, byte_i_ref,
1921 "element_name_index", THREAD);
1922
1923 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1924 ("element_name_index=%d", element_name_index));
1925
1926 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1927 byte_i_ref, THREAD)) {
1928 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1929 ("bad element_value at %d", calc_num_element_value_pairs));
1930 // propagate failure back to caller
1931 return false;
1932 }
1933 } // end for each component
1934 assert(num_element_value_pairs == calc_num_element_value_pairs,
1935 "sanity check");
1936
1937 return true;
1938 } // end rewrite_cp_refs_in_annotation_struct()
1939
1940
1941 // Rewrite a constant pool reference at the current position in
1942 // annotations_typeArray if needed. Returns the original constant
1943 // pool reference if a rewrite was not needed or the new constant
1944 // pool reference if a rewrite was needed.
1945 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1946 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1947 const char * trace_mesg, TRAPS) {
1948
1949 address cp_index_addr = (address)
1950 annotations_typeArray->adr_at(byte_i_ref);
1951 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1952 u2 new_cp_index = find_new_index(old_cp_index);
1953 if (new_cp_index != 0) {
1954 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("mapped old %s=%d", trace_mesg, old_cp_index));
1955 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1956 old_cp_index = new_cp_index;
1957 }
1958 byte_i_ref += 2;
1959 return old_cp_index;
1960 }
1961
1962
1963 // Rewrite constant pool references in the element_value portion of an
1964 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1965 // the 2nd-edition of the VM spec:
1966 //
1967 // struct element_value {
1968 // u1 tag;
1969 // union {
1970 // u2 const_value_index;
1971 // {
1972 // u2 type_name_index;
1973 // u2 const_name_index;
1974 // } enum_const_value;
1975 // u2 class_info_index;
1976 // annotation annotation_value;
1977 // struct {
1978 // u2 num_values;
1979 // element_value values[num_values];
1980 // } array_value;
1981 // } value;
1982 // }
1983 //
1984 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1985 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1986
1987 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1988 // not enough room for a tag let alone the rest of an element_value
1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1990 ("length() is too small for a tag"));
1991 return false;
1992 }
1993
1994 u1 tag = annotations_typeArray->at(byte_i_ref);
1995 byte_i_ref++;
1996 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1997
1998 switch (tag) {
1999 // These BaseType tag values are from Table 4.2 in VM spec:
2000 case 'B': // byte
2001 case 'C': // char
2002 case 'D': // double
2003 case 'F': // float
2004 case 'I': // int
2005 case 'J': // long
2006 case 'S': // short
2007 case 'Z': // boolean
2008
2009 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2010 // the VM spec:
2011 case 's':
2012 {
2013 // For the above tag values (including the BaseType values),
2014 // value.const_value_index is right union field.
2015
2016 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2017 // not enough room for a const_value_index
2018 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2019 ("length() is too small for a const_value_index"));
2020 return false;
2021 }
2022
2023 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2024 annotations_typeArray, byte_i_ref,
2025 "const_value_index", THREAD);
2026
2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2028 ("const_value_index=%d", const_value_index));
2029 } break;
2030
2031 case 'e':
2032 {
2033 // for the above tag value, value.enum_const_value is right union field
2034
2035 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2036 // not enough room for a enum_const_value
2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2038 ("length() is too small for a enum_const_value"));
2039 return false;
2040 }
2041
2042 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2043 annotations_typeArray, byte_i_ref,
2044 "type_name_index", THREAD);
2045
2046 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2047 annotations_typeArray, byte_i_ref,
2048 "const_name_index", THREAD);
2049
2050 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2051 ("type_name_index=%d const_name_index=%d", type_name_index,
2052 const_name_index));
2053 } break;
2054
2055 case 'c':
2056 {
2057 // for the above tag value, value.class_info_index is right union field
2058
2059 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2060 // not enough room for a class_info_index
2061 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2062 ("length() is too small for a class_info_index"));
2063 return false;
2064 }
2065
2066 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2067 annotations_typeArray, byte_i_ref,
2068 "class_info_index", THREAD);
2069
2070 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2071 ("class_info_index=%d", class_info_index));
2072 } break;
2073
2074 case '@':
2075 // For the above tag value, value.attr_value is the right union
2076 // field. This is a nested annotation.
2077 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2078 byte_i_ref, THREAD)) {
2079 // propagate failure back to caller
2080 return false;
2081 }
2082 break;
2083
2084 case '[':
2085 {
2086 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2087 // not enough room for a num_values field
2088 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2089 ("length() is too small for a num_values field"));
2090 return false;
2091 }
2092
2093 // For the above tag value, value.array_value is the right union
2094 // field. This is an array of nested element_value.
2095 u2 num_values = Bytes::get_Java_u2((address)
2096 annotations_typeArray->adr_at(byte_i_ref));
2097 byte_i_ref += 2;
2098 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2099
2100 int calc_num_values = 0;
2101 for (; calc_num_values < num_values; calc_num_values++) {
2102 if (!rewrite_cp_refs_in_element_value(
2103 annotations_typeArray, byte_i_ref, THREAD)) {
2104 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2105 ("bad nested element_value at %d", calc_num_values));
2106 // propagate failure back to caller
2107 return false;
2108 }
2109 }
2110 assert(num_values == calc_num_values, "sanity check");
2111 } break;
2112
2113 default:
2114 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2115 return false;
2116 } // end decode tag field
2117
2118 return true;
2119 } // end rewrite_cp_refs_in_element_value()
2120
2121
2122 // Rewrite constant pool references in a fields_annotations field.
2123 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2124 instanceKlassHandle scratch_class, TRAPS) {
2125
2126 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2127
2128 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2129 // no fields_annotations so nothing to do
2130 return true;
2131 }
2132
2133 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2134 ("fields_annotations length=%d", fields_annotations->length()));
2135
2136 for (int i = 0; i < fields_annotations->length(); i++) {
2137 AnnotationArray* field_annotations = fields_annotations->at(i);
2138 if (field_annotations == NULL || field_annotations->length() == 0) {
2139 // this field does not have any annotations so skip it
2140 continue;
2141 }
2142
2143 int byte_i = 0; // byte index into field_annotations
2144 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2145 THREAD)) {
2146 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2147 ("bad field_annotations at %d", i));
2148 // propagate failure back to caller
2149 return false;
2150 }
2151 }
2152
2153 return true;
2154 } // end rewrite_cp_refs_in_fields_annotations()
2155
2156
2157 // Rewrite constant pool references in a methods_annotations field.
2158 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2159 instanceKlassHandle scratch_class, TRAPS) {
2160
2161 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2162 Method* m = scratch_class->methods()->at(i);
2163 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2164
2165 if (method_annotations == NULL || method_annotations->length() == 0) {
2166 // this method does not have any annotations so skip it
2167 continue;
2168 }
2169
2170 int byte_i = 0; // byte index into method_annotations
2171 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2172 THREAD)) {
2173 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2174 ("bad method_annotations at %d", i));
2175 // propagate failure back to caller
2176 return false;
2177 }
2178 }
2179
2180 return true;
2181 } // end rewrite_cp_refs_in_methods_annotations()
2182
2183
2184 // Rewrite constant pool references in a methods_parameter_annotations
2185 // field. This "structure" is adapted from the
2186 // RuntimeVisibleParameterAnnotations_attribute described in section
2187 // 4.8.17 of the 2nd-edition of the VM spec:
2188 //
2189 // methods_parameter_annotations_typeArray {
2190 // u1 num_parameters;
2191 // {
2192 // u2 num_annotations;
2193 // annotation annotations[num_annotations];
2194 // } parameter_annotations[num_parameters];
2195 // }
2196 //
2197 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2198 instanceKlassHandle scratch_class, TRAPS) {
2199
2200 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2201 Method* m = scratch_class->methods()->at(i);
2202 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2203 if (method_parameter_annotations == NULL
2204 || method_parameter_annotations->length() == 0) {
2205 // this method does not have any parameter annotations so skip it
2206 continue;
2207 }
2208
2209 if (method_parameter_annotations->length() < 1) {
2210 // not enough room for a num_parameters field
2211 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2212 ("length() is too small for a num_parameters field at %d", i));
2213 return false;
2214 }
2215
2216 int byte_i = 0; // byte index into method_parameter_annotations
2217
2218 u1 num_parameters = method_parameter_annotations->at(byte_i);
2219 byte_i++;
2220
2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2222 ("num_parameters=%d", num_parameters));
2223
2224 int calc_num_parameters = 0;
2225 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2226 if (!rewrite_cp_refs_in_annotations_typeArray(
2227 method_parameter_annotations, byte_i, THREAD)) {
2228 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2229 ("bad method_parameter_annotations at %d", calc_num_parameters));
2230 // propagate failure back to caller
2231 return false;
2232 }
2233 }
2234 assert(num_parameters == calc_num_parameters, "sanity check");
2235 }
2236
2237 return true;
2238 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2239
2240
2241 // Rewrite constant pool references in a methods_default_annotations
2242 // field. This "structure" is adapted from the AnnotationDefault_attribute
2243 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2244 //
2245 // methods_default_annotations_typeArray {
2246 // element_value default_value;
2247 // }
2248 //
2249 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2250 instanceKlassHandle scratch_class, TRAPS) {
2251
2252 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2253 Method* m = scratch_class->methods()->at(i);
2254 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2255 if (method_default_annotations == NULL
2256 || method_default_annotations->length() == 0) {
2257 // this method does not have any default annotations so skip it
2258 continue;
2259 }
2260
2261 int byte_i = 0; // byte index into method_default_annotations
2262
2263 if (!rewrite_cp_refs_in_element_value(
2264 method_default_annotations, byte_i, THREAD)) {
2265 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2266 ("bad default element_value at %d", i));
2267 // propagate failure back to caller
2268 return false;
2269 }
2270 }
2271
2272 return true;
2273 } // end rewrite_cp_refs_in_methods_default_annotations()
2274
2275
2276 // Rewrite constant pool references in a class_type_annotations field.
2277 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2278 instanceKlassHandle scratch_class, TRAPS) {
2279
2280 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2281 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2282 // no class_type_annotations so nothing to do
2283 return true;
2284 }
2285
2286 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2287 ("class_type_annotations length=%d", class_type_annotations->length()));
2288
2289 int byte_i = 0; // byte index into class_type_annotations
2290 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2291 byte_i, "ClassFile", THREAD);
2292 } // end rewrite_cp_refs_in_class_type_annotations()
2293
2294
2295 // Rewrite constant pool references in a fields_type_annotations field.
2296 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2297 instanceKlassHandle scratch_class, TRAPS) {
2298
2299 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2300 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2301 // no fields_type_annotations so nothing to do
2302 return true;
2303 }
2304
2305 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2306 ("fields_type_annotations length=%d", fields_type_annotations->length()));
2307
2308 for (int i = 0; i < fields_type_annotations->length(); i++) {
2309 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2310 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2311 // this field does not have any annotations so skip it
2312 continue;
2313 }
2314
2315 int byte_i = 0; // byte index into field_type_annotations
2316 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2317 byte_i, "field_info", THREAD)) {
2318 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2319 ("bad field_type_annotations at %d", i));
2320 // propagate failure back to caller
2321 return false;
2322 }
2323 }
2324
2325 return true;
2326 } // end rewrite_cp_refs_in_fields_type_annotations()
2327
2328
2329 // Rewrite constant pool references in a methods_type_annotations field.
2330 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2331 instanceKlassHandle scratch_class, TRAPS) {
2332
2333 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2334 Method* m = scratch_class->methods()->at(i);
2335 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2336
2337 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2338 // this method does not have any annotations so skip it
2339 continue;
2340 }
2341
2342 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2343 ("methods type_annotations length=%d", method_type_annotations->length()));
2344
2345 int byte_i = 0; // byte index into method_type_annotations
2346 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2347 byte_i, "method_info", THREAD)) {
2348 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2349 ("bad method_type_annotations at %d", i));
2350 // propagate failure back to caller
2351 return false;
2352 }
2353 }
2354
2355 return true;
2356 } // end rewrite_cp_refs_in_methods_type_annotations()
2357
2358
2359 // Rewrite constant pool references in a type_annotations
2360 // field. This "structure" is adapted from the
2361 // RuntimeVisibleTypeAnnotations_attribute described in
2362 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2363 //
2364 // type_annotations_typeArray {
2365 // u2 num_annotations;
2366 // type_annotation annotations[num_annotations];
2367 // }
2368 //
2369 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2370 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2371 const char * location_mesg, TRAPS) {
2372
2373 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2374 // not enough room for num_annotations field
2375 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2376 ("length() is too small for num_annotations field"));
2377 return false;
2378 }
2379
2380 u2 num_annotations = Bytes::get_Java_u2((address)
2381 type_annotations_typeArray->adr_at(byte_i_ref));
2382 byte_i_ref += 2;
2383
2384 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2385 ("num_type_annotations=%d", num_annotations));
2386
2387 int calc_num_annotations = 0;
2388 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2389 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2390 byte_i_ref, location_mesg, THREAD)) {
2391 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2392 ("bad type_annotation_struct at %d", calc_num_annotations));
2393 // propagate failure back to caller
2394 return false;
2395 }
2396 }
2397 assert(num_annotations == calc_num_annotations, "sanity check");
2398
2399 if (byte_i_ref != type_annotations_typeArray->length()) {
2400 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2401 ("read wrong amount of bytes at end of processing "
2402 "type_annotations_typeArray (%d of %d bytes were read)",
2403 byte_i_ref, type_annotations_typeArray->length()));
2404 return false;
2405 }
2406
2407 return true;
2408 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2409
2410
2411 // Rewrite constant pool references in a type_annotation
2412 // field. This "structure" is adapted from the
2413 // RuntimeVisibleTypeAnnotations_attribute described in
2414 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2415 //
2416 // type_annotation {
2417 // u1 target_type;
2418 // union {
2419 // type_parameter_target;
2420 // supertype_target;
2421 // type_parameter_bound_target;
2422 // empty_target;
2423 // method_formal_parameter_target;
2424 // throws_target;
2425 // localvar_target;
2426 // catch_target;
2427 // offset_target;
2428 // type_argument_target;
2429 // } target_info;
2430 // type_path target_path;
2431 // annotation anno;
2432 // }
2433 //
2434 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2435 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2436 const char * location_mesg, TRAPS) {
2437
2438 if (!skip_type_annotation_target(type_annotations_typeArray,
2439 byte_i_ref, location_mesg, THREAD)) {
2440 return false;
2441 }
2442
2443 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2444 byte_i_ref, THREAD)) {
2445 return false;
2446 }
2447
2448 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2449 byte_i_ref, THREAD)) {
2450 return false;
2451 }
2452
2453 return true;
2454 } // end rewrite_cp_refs_in_type_annotation_struct()
2455
2456
2457 // Read, verify and skip over the target_type and target_info part
2458 // so that rewriting can continue in the later parts of the struct.
2459 //
2460 // u1 target_type;
2461 // union {
2462 // type_parameter_target;
2463 // supertype_target;
2464 // type_parameter_bound_target;
2465 // empty_target;
2466 // method_formal_parameter_target;
2467 // throws_target;
2468 // localvar_target;
2469 // catch_target;
2470 // offset_target;
2471 // type_argument_target;
2472 // } target_info;
2473 //
2474 bool VM_RedefineClasses::skip_type_annotation_target(
2475 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2476 const char * location_mesg, TRAPS) {
2477
2478 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2479 // not enough room for a target_type let alone the rest of a type_annotation
2480 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2481 ("length() is too small for a target_type"));
2482 return false;
2483 }
2484
2485 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2486 byte_i_ref += 1;
2487 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type));
2488 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg));
2489
2490 // Skip over target_info
2491 switch (target_type) {
2492 case 0x00:
2493 // kind: type parameter declaration of generic class or interface
2494 // location: ClassFile
2495 case 0x01:
2496 // kind: type parameter declaration of generic method or constructor
2497 // location: method_info
2498
2499 {
2500 // struct:
2501 // type_parameter_target {
2502 // u1 type_parameter_index;
2503 // }
2504 //
2505 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2506 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2507 ("length() is too small for a type_parameter_target"));
2508 return false;
2509 }
2510
2511 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2512 byte_i_ref += 1;
2513
2514 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2515 ("type_parameter_target: type_parameter_index=%d",
2516 type_parameter_index));
2517 } break;
2518
2519 case 0x10:
2520 // kind: type in extends clause of class or interface declaration
2521 // (including the direct superclass of an anonymous class declaration),
2522 // or in implements clause of interface declaration
2523 // location: ClassFile
2524
2525 {
2526 // struct:
2527 // supertype_target {
2528 // u2 supertype_index;
2529 // }
2530 //
2531 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2532 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2533 ("length() is too small for a supertype_target"));
2534 return false;
2535 }
2536
2537 u2 supertype_index = Bytes::get_Java_u2((address)
2538 type_annotations_typeArray->adr_at(byte_i_ref));
2539 byte_i_ref += 2;
2540
2541 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2542 ("supertype_target: supertype_index=%d", supertype_index));
2543 } break;
2544
2545 case 0x11:
2546 // kind: type in bound of type parameter declaration of generic class or interface
2547 // location: ClassFile
2548 case 0x12:
2549 // kind: type in bound of type parameter declaration of generic method or constructor
2550 // location: method_info
2551
2552 {
2553 // struct:
2554 // type_parameter_bound_target {
2555 // u1 type_parameter_index;
2556 // u1 bound_index;
2557 // }
2558 //
2559 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2560 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2561 ("length() is too small for a type_parameter_bound_target"));
2562 return false;
2563 }
2564
2565 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2566 byte_i_ref += 1;
2567 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2568 byte_i_ref += 1;
2569
2570 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2571 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d",
2572 type_parameter_index, bound_index));
2573 } break;
2574
2575 case 0x13:
2576 // kind: type in field declaration
2577 // location: field_info
2578 case 0x14:
2579 // kind: return type of method, or type of newly constructed object
2580 // location: method_info
2581 case 0x15:
2582 // kind: receiver type of method or constructor
2583 // location: method_info
2584
2585 {
2586 // struct:
2587 // empty_target {
2588 // }
2589 //
2590 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2591 ("empty_target"));
2592 } break;
2593
2594 case 0x16:
2595 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2596 // location: method_info
2597
2598 {
2599 // struct:
2600 // formal_parameter_target {
2601 // u1 formal_parameter_index;
2602 // }
2603 //
2604 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2605 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2606 ("length() is too small for a formal_parameter_target"));
2607 return false;
2608 }
2609
2610 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2611 byte_i_ref += 1;
2612
2613 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2614 ("formal_parameter_target: formal_parameter_index=%d",
2615 formal_parameter_index));
2616 } break;
2617
2618 case 0x17:
2619 // kind: type in throws clause of method or constructor
2620 // location: method_info
2621
2622 {
2623 // struct:
2624 // throws_target {
2625 // u2 throws_type_index
2626 // }
2627 //
2628 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2629 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2630 ("length() is too small for a throws_target"));
2631 return false;
2632 }
2633
2634 u2 throws_type_index = Bytes::get_Java_u2((address)
2635 type_annotations_typeArray->adr_at(byte_i_ref));
2636 byte_i_ref += 2;
2637
2638 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2639 ("throws_target: throws_type_index=%d", throws_type_index));
2640 } break;
2641
2642 case 0x40:
2643 // kind: type in local variable declaration
2644 // location: Code
2645 case 0x41:
2646 // kind: type in resource variable declaration
2647 // location: Code
2648
2649 {
2650 // struct:
2651 // localvar_target {
2652 // u2 table_length;
2653 // struct {
2654 // u2 start_pc;
2655 // u2 length;
2656 // u2 index;
2657 // } table[table_length];
2658 // }
2659 //
2660 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2661 // not enough room for a table_length let alone the rest of a localvar_target
2662 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2663 ("length() is too small for a localvar_target table_length"));
2664 return false;
2665 }
2666
2667 u2 table_length = Bytes::get_Java_u2((address)
2668 type_annotations_typeArray->adr_at(byte_i_ref));
2669 byte_i_ref += 2;
2670
2671 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2672 ("localvar_target: table_length=%d", table_length));
2673
2674 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2675 int table_size = table_length * table_struct_size;
2676
2677 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2678 // not enough room for a table
2679 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2680 ("length() is too small for a table array of length %d", table_length));
2681 return false;
2682 }
2683
2684 // Skip over table
2685 byte_i_ref += table_size;
2686 } break;
2687
2688 case 0x42:
2689 // kind: type in exception parameter declaration
2690 // location: Code
2691
2692 {
2693 // struct:
2694 // catch_target {
2695 // u2 exception_table_index;
2696 // }
2697 //
2698 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2699 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2700 ("length() is too small for a catch_target"));
2701 return false;
2702 }
2703
2704 u2 exception_table_index = Bytes::get_Java_u2((address)
2705 type_annotations_typeArray->adr_at(byte_i_ref));
2706 byte_i_ref += 2;
2707
2708 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2709 ("catch_target: exception_table_index=%d", exception_table_index));
2710 } break;
2711
2712 case 0x43:
2713 // kind: type in instanceof expression
2714 // location: Code
2715 case 0x44:
2716 // kind: type in new expression
2717 // location: Code
2718 case 0x45:
2719 // kind: type in method reference expression using ::new
2720 // location: Code
2721 case 0x46:
2722 // kind: type in method reference expression using ::Identifier
2723 // location: Code
2724
2725 {
2726 // struct:
2727 // offset_target {
2728 // u2 offset;
2729 // }
2730 //
2731 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2732 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2733 ("length() is too small for a offset_target"));
2734 return false;
2735 }
2736
2737 u2 offset = Bytes::get_Java_u2((address)
2738 type_annotations_typeArray->adr_at(byte_i_ref));
2739 byte_i_ref += 2;
2740
2741 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2742 ("offset_target: offset=%d", offset));
2743 } break;
2744
2745 case 0x47:
2746 // kind: type in cast expression
2747 // location: Code
2748 case 0x48:
2749 // kind: type argument for generic constructor in new expression or
2750 // explicit constructor invocation statement
2751 // location: Code
2752 case 0x49:
2753 // kind: type argument for generic method in method invocation expression
2754 // location: Code
2755 case 0x4A:
2756 // kind: type argument for generic constructor in method reference expression using ::new
2757 // location: Code
2758 case 0x4B:
2759 // kind: type argument for generic method in method reference expression using ::Identifier
2760 // location: Code
2761
2762 {
2763 // struct:
2764 // type_argument_target {
2765 // u2 offset;
2766 // u1 type_argument_index;
2767 // }
2768 //
2769 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2770 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2771 ("length() is too small for a type_argument_target"));
2772 return false;
2773 }
2774
2775 u2 offset = Bytes::get_Java_u2((address)
2776 type_annotations_typeArray->adr_at(byte_i_ref));
2777 byte_i_ref += 2;
2778 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2779 byte_i_ref += 1;
2780
2781 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2782 ("type_argument_target: offset=%d, type_argument_index=%d",
2783 offset, type_argument_index));
2784 } break;
2785
2786 default:
2787 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2788 ("unknown target_type"));
2789 #ifdef ASSERT
2790 ShouldNotReachHere();
2791 #endif
2792 return false;
2793 }
2794
2795 return true;
2796 } // end skip_type_annotation_target()
2797
2798
2799 // Read, verify and skip over the type_path part so that rewriting
2800 // can continue in the later parts of the struct.
2801 //
2802 // type_path {
2803 // u1 path_length;
2804 // {
2805 // u1 type_path_kind;
2806 // u1 type_argument_index;
2807 // } path[path_length];
2808 // }
2809 //
2810 bool VM_RedefineClasses::skip_type_annotation_type_path(
2811 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2812
2813 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2814 // not enough room for a path_length let alone the rest of the type_path
2815 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2816 ("length() is too small for a type_path"));
2817 return false;
2818 }
2819
2820 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2821 byte_i_ref += 1;
2822
2823 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2824 ("type_path: path_length=%d", path_length));
2825
2826 int calc_path_length = 0;
2827 for (; calc_path_length < path_length; calc_path_length++) {
2828 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2829 // not enough room for a path
2830 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2831 ("length() is too small for path entry %d of %d",
2832 calc_path_length, path_length));
2833 return false;
2834 }
2835
2836 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2837 byte_i_ref += 1;
2838 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2839 byte_i_ref += 1;
2840
2841 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2842 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2843 calc_path_length, type_path_kind, type_argument_index));
2844
2845 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2846 // not enough room for a path
2847 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2848 ("inconsistent type_path values"));
2849 return false;
2850 }
2851 }
2852 assert(path_length == calc_path_length, "sanity check");
2853
2854 return true;
2855 } // end skip_type_annotation_type_path()
2856
2857
2858 // Rewrite constant pool references in the method's stackmap table.
2859 // These "structures" are adapted from the StackMapTable_attribute that
2860 // is described in section 4.8.4 of the 6.0 version of the VM spec
2861 // (dated 2005.10.26):
2862 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2863 //
2864 // stack_map {
2865 // u2 number_of_entries;
2866 // stack_map_frame entries[number_of_entries];
2867 // }
2868 //
2869 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2870 const methodHandle& method, TRAPS) {
2871
2872 if (!method->has_stackmap_table()) {
2873 return;
2874 }
2875
2876 AnnotationArray* stackmap_data = method->stackmap_data();
2877 address stackmap_p = (address)stackmap_data->adr_at(0);
2878 address stackmap_end = stackmap_p + stackmap_data->length();
2879
2880 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2881 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2882 stackmap_p += 2;
2883
2884 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2885 ("number_of_entries=%u", number_of_entries));
2886
2887 // walk through each stack_map_frame
2888 u2 calc_number_of_entries = 0;
2889 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2890 // The stack_map_frame structure is a u1 frame_type followed by
2891 // 0 or more bytes of data:
2892 //
2893 // union stack_map_frame {
2894 // same_frame;
2895 // same_locals_1_stack_item_frame;
2896 // same_locals_1_stack_item_frame_extended;
2897 // chop_frame;
2898 // same_frame_extended;
2899 // append_frame;
2900 // full_frame;
2901 // }
2902
2903 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2904 u1 frame_type = *stackmap_p;
2905 stackmap_p++;
2906
2907 // same_frame {
2908 // u1 frame_type = SAME; /* 0-63 */
2909 // }
2910 if (frame_type <= 63) {
2911 // nothing more to do for same_frame
2912 }
2913
2914 // same_locals_1_stack_item_frame {
2915 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2916 // verification_type_info stack[1];
2917 // }
2918 else if (frame_type >= 64 && frame_type <= 127) {
2919 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2920 calc_number_of_entries, frame_type, THREAD);
2921 }
2922
2923 // reserved for future use
2924 else if (frame_type >= 128 && frame_type <= 246) {
2925 // nothing more to do for reserved frame_types
2926 }
2927
2928 // same_locals_1_stack_item_frame_extended {
2929 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2930 // u2 offset_delta;
2931 // verification_type_info stack[1];
2932 // }
2933 else if (frame_type == 247) {
2934 stackmap_p += 2;
2935 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2936 calc_number_of_entries, frame_type, THREAD);
2937 }
2938
2939 // chop_frame {
2940 // u1 frame_type = CHOP; /* 248-250 */
2941 // u2 offset_delta;
2942 // }
2943 else if (frame_type >= 248 && frame_type <= 250) {
2944 stackmap_p += 2;
2945 }
2946
2947 // same_frame_extended {
2948 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2949 // u2 offset_delta;
2950 // }
2951 else if (frame_type == 251) {
2952 stackmap_p += 2;
2953 }
2954
2955 // append_frame {
2956 // u1 frame_type = APPEND; /* 252-254 */
2957 // u2 offset_delta;
2958 // verification_type_info locals[frame_type - 251];
2959 // }
2960 else if (frame_type >= 252 && frame_type <= 254) {
2961 assert(stackmap_p + 2 <= stackmap_end,
2962 "no room for offset_delta");
2963 stackmap_p += 2;
2964 u1 len = frame_type - 251;
2965 for (u1 i = 0; i < len; i++) {
2966 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2967 calc_number_of_entries, frame_type, THREAD);
2968 }
2969 }
2970
2971 // full_frame {
2972 // u1 frame_type = FULL_FRAME; /* 255 */
2973 // u2 offset_delta;
2974 // u2 number_of_locals;
2975 // verification_type_info locals[number_of_locals];
2976 // u2 number_of_stack_items;
2977 // verification_type_info stack[number_of_stack_items];
2978 // }
2979 else if (frame_type == 255) {
2980 assert(stackmap_p + 2 + 2 <= stackmap_end,
2981 "no room for smallest full_frame");
2982 stackmap_p += 2;
2983
2984 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2985 stackmap_p += 2;
2986
2987 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2988 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2989 calc_number_of_entries, frame_type, THREAD);
2990 }
2991
2992 // Use the largest size for the number_of_stack_items, but only get
2993 // the right number of bytes.
2994 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2995 stackmap_p += 2;
2996
2997 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2998 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2999 calc_number_of_entries, frame_type, THREAD);
3000 }
3001 }
3002 } // end while there is a stack_map_frame
3003 assert(number_of_entries == calc_number_of_entries, "sanity check");
3004 } // end rewrite_cp_refs_in_stack_map_table()
3005
3006
3007 // Rewrite constant pool references in the verification type info
3008 // portion of the method's stackmap table. These "structures" are
3009 // adapted from the StackMapTable_attribute that is described in
3010 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3011 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3012 //
3013 // The verification_type_info structure is a u1 tag followed by 0 or
3014 // more bytes of data:
3015 //
3016 // union verification_type_info {
3017 // Top_variable_info;
3018 // Integer_variable_info;
3019 // Float_variable_info;
3020 // Long_variable_info;
3021 // Double_variable_info;
3022 // Null_variable_info;
3023 // UninitializedThis_variable_info;
3024 // Object_variable_info;
3025 // Uninitialized_variable_info;
3026 // }
3027 //
3028 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3029 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3030 u1 frame_type, TRAPS) {
3031
3032 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3033 u1 tag = *stackmap_p_ref;
3034 stackmap_p_ref++;
3035
3036 switch (tag) {
3037 // Top_variable_info {
3038 // u1 tag = ITEM_Top; /* 0 */
3039 // }
3040 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3041 case 0: // fall through
3042
3043 // Integer_variable_info {
3044 // u1 tag = ITEM_Integer; /* 1 */
3045 // }
3046 case ITEM_Integer: // fall through
3047
3048 // Float_variable_info {
3049 // u1 tag = ITEM_Float; /* 2 */
3050 // }
3051 case ITEM_Float: // fall through
3052
3053 // Double_variable_info {
3054 // u1 tag = ITEM_Double; /* 3 */
3055 // }
3056 case ITEM_Double: // fall through
3057
3058 // Long_variable_info {
3059 // u1 tag = ITEM_Long; /* 4 */
3060 // }
3061 case ITEM_Long: // fall through
3062
3063 // Null_variable_info {
3064 // u1 tag = ITEM_Null; /* 5 */
3065 // }
3066 case ITEM_Null: // fall through
3067
3068 // UninitializedThis_variable_info {
3069 // u1 tag = ITEM_UninitializedThis; /* 6 */
3070 // }
3071 case ITEM_UninitializedThis:
3072 // nothing more to do for the above tag types
3073 break;
3074
3075 // Object_variable_info {
3076 // u1 tag = ITEM_Object; /* 7 */
3077 // u2 cpool_index;
3078 // }
3079 case ITEM_Object:
3080 {
3081 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3082 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3083 u2 new_cp_index = find_new_index(cpool_index);
3084 if (new_cp_index != 0) {
3085 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3086 ("mapped old cpool_index=%d", cpool_index));
3087 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3088 cpool_index = new_cp_index;
3089 }
3090 stackmap_p_ref += 2;
3091
3092 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3093 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
3094 frame_type, cpool_index));
3095 } break;
3096
3097 // Uninitialized_variable_info {
3098 // u1 tag = ITEM_Uninitialized; /* 8 */
3099 // u2 offset;
3100 // }
3101 case ITEM_Uninitialized:
3102 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3103 stackmap_p_ref += 2;
3104 break;
3105
3106 default:
3107 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3108 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
3109 ShouldNotReachHere();
3110 break;
3111 } // end switch (tag)
3112 } // end rewrite_cp_refs_in_verification_type_info()
3113
3114
3115 // Change the constant pool associated with klass scratch_class to
3116 // scratch_cp. If shrink is true, then scratch_cp_length elements
3117 // are copied from scratch_cp to a smaller constant pool and the
3118 // smaller constant pool is associated with scratch_class.
3119 void VM_RedefineClasses::set_new_constant_pool(
3120 ClassLoaderData* loader_data,
3121 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
3122 int scratch_cp_length, TRAPS) {
3123 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3124
3125 // scratch_cp is a merged constant pool and has enough space for a
3126 // worst case merge situation. We want to associate the minimum
3127 // sized constant pool with the klass to save space.
3128 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3129 constantPoolHandle smaller_cp(THREAD, cp);
3130
3131 // preserve version() value in the smaller copy
3132 int version = scratch_cp->version();
3133 assert(version != 0, "sanity check");
3134 smaller_cp->set_version(version);
3135
3136 // attach klass to new constant pool
3137 // reference to the cp holder is needed for copy_operands()
3138 smaller_cp->set_pool_holder(scratch_class());
3139
3140 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3141 if (HAS_PENDING_EXCEPTION) {
3142 // Exception is handled in the caller
3143 loader_data->add_to_deallocate_list(smaller_cp());
3144 return;
3145 }
3146 scratch_cp = smaller_cp;
3147
3148 // attach new constant pool to klass
3149 scratch_class->set_constants(scratch_cp());
3150
3151 int i; // for portability
3152
3153 // update each field in klass to use new constant pool indices as needed
3154 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3155 jshort cur_index = fs.name_index();
3156 jshort new_index = find_new_index(cur_index);
3157 if (new_index != 0) {
3158 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3159 ("field-name_index change: %d to %d", cur_index, new_index));
3160 fs.set_name_index(new_index);
3161 }
3162 cur_index = fs.signature_index();
3163 new_index = find_new_index(cur_index);
3164 if (new_index != 0) {
3165 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3166 ("field-signature_index change: %d to %d", cur_index, new_index));
3167 fs.set_signature_index(new_index);
3168 }
3169 cur_index = fs.initval_index();
3170 new_index = find_new_index(cur_index);
3171 if (new_index != 0) {
3172 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3173 ("field-initval_index change: %d to %d", cur_index, new_index));
3174 fs.set_initval_index(new_index);
3175 }
3176 cur_index = fs.generic_signature_index();
3177 new_index = find_new_index(cur_index);
3178 if (new_index != 0) {
3179 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3180 ("field-generic_signature change: %d to %d", cur_index, new_index));
3181 fs.set_generic_signature_index(new_index);
3182 }
3183 } // end for each field
3184
3185 // Update constant pool indices in the inner classes info to use
3186 // new constant indices as needed. The inner classes info is a
3187 // quadruple:
3188 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3189 InnerClassesIterator iter(scratch_class);
3190 for (; !iter.done(); iter.next()) {
3191 int cur_index = iter.inner_class_info_index();
3192 if (cur_index == 0) {
3193 continue; // JVM spec. allows null inner class refs so skip it
3194 }
3195 int new_index = find_new_index(cur_index);
3196 if (new_index != 0) {
3197 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3198 ("inner_class_info change: %d to %d", cur_index, new_index));
3199 iter.set_inner_class_info_index(new_index);
3200 }
3201 cur_index = iter.outer_class_info_index();
3202 new_index = find_new_index(cur_index);
3203 if (new_index != 0) {
3204 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3205 ("outer_class_info change: %d to %d", cur_index, new_index));
3206 iter.set_outer_class_info_index(new_index);
3207 }
3208 cur_index = iter.inner_name_index();
3209 new_index = find_new_index(cur_index);
3210 if (new_index != 0) {
3211 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3212 ("inner_name change: %d to %d", cur_index, new_index));
3213 iter.set_inner_name_index(new_index);
3214 }
3215 } // end for each inner class
3216
3217 // Attach each method in klass to the new constant pool and update
3218 // to use new constant pool indices as needed:
3219 Array<Method*>* methods = scratch_class->methods();
3220 for (i = methods->length() - 1; i >= 0; i--) {
3221 methodHandle method(THREAD, methods->at(i));
3222 method->set_constants(scratch_cp());
3223
3224 int new_index = find_new_index(method->name_index());
3225 if (new_index != 0) {
3226 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3227 ("method-name_index change: %d to %d", method->name_index(),
3228 new_index));
3229 method->set_name_index(new_index);
3230 }
3231 new_index = find_new_index(method->signature_index());
3232 if (new_index != 0) {
3233 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3234 ("method-signature_index change: %d to %d",
3235 method->signature_index(), new_index));
3236 method->set_signature_index(new_index);
3237 }
3238 new_index = find_new_index(method->generic_signature_index());
3239 if (new_index != 0) {
3240 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3241 ("method-generic_signature_index change: %d to %d",
3242 method->generic_signature_index(), new_index));
3243 method->set_generic_signature_index(new_index);
3244 }
3245
3246 // Update constant pool indices in the method's checked exception
3247 // table to use new constant indices as needed.
3248 int cext_length = method->checked_exceptions_length();
3249 if (cext_length > 0) {
3250 CheckedExceptionElement * cext_table =
3251 method->checked_exceptions_start();
3252 for (int j = 0; j < cext_length; j++) {
3253 int cur_index = cext_table[j].class_cp_index;
3254 int new_index = find_new_index(cur_index);
3255 if (new_index != 0) {
3256 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3257 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
3258 cext_table[j].class_cp_index = (u2)new_index;
3259 }
3260 } // end for each checked exception table entry
3261 } // end if there are checked exception table entries
3262
3263 // Update each catch type index in the method's exception table
3264 // to use new constant pool indices as needed. The exception table
3265 // holds quadruple entries of the form:
3266 // (beg_bci, end_bci, handler_bci, klass_index)
3267
3268 ExceptionTable ex_table(method());
3269 int ext_length = ex_table.length();
3270
3271 for (int j = 0; j < ext_length; j ++) {
3272 int cur_index = ex_table.catch_type_index(j);
3273 int new_index = find_new_index(cur_index);
3274 if (new_index != 0) {
3275 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3276 ("ext-klass_index change: %d to %d", cur_index, new_index));
3277 ex_table.set_catch_type_index(j, new_index);
3278 }
3279 } // end for each exception table entry
3280
3281 // Update constant pool indices in the method's local variable
3282 // table to use new constant indices as needed. The local variable
3283 // table hold sextuple entries of the form:
3284 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3285 int lvt_length = method->localvariable_table_length();
3286 if (lvt_length > 0) {
3287 LocalVariableTableElement * lv_table =
3288 method->localvariable_table_start();
3289 for (int j = 0; j < lvt_length; j++) {
3290 int cur_index = lv_table[j].name_cp_index;
3291 int new_index = find_new_index(cur_index);
3292 if (new_index != 0) {
3293 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3294 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
3295 lv_table[j].name_cp_index = (u2)new_index;
3296 }
3297 cur_index = lv_table[j].descriptor_cp_index;
3298 new_index = find_new_index(cur_index);
3299 if (new_index != 0) {
3300 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3301 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
3302 new_index));
3303 lv_table[j].descriptor_cp_index = (u2)new_index;
3304 }
3305 cur_index = lv_table[j].signature_cp_index;
3306 new_index = find_new_index(cur_index);
3307 if (new_index != 0) {
3308 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3309 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
3310 lv_table[j].signature_cp_index = (u2)new_index;
3311 }
3312 } // end for each local variable table entry
3313 } // end if there are local variable table entries
3314
3315 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3316 } // end for each method
3317 } // end set_new_constant_pool()
3318
3319
3320 // Unevolving classes may point to methods of the_class directly
3321 // from their constant pool caches, itables, and/or vtables. We
3322 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3323 // to fix up these pointers.
3324
3325 // Adjust cpools and vtables closure
3326 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3327
3328 // This is a very busy routine. We don't want too much tracing
3329 // printed out.
3330 bool trace_name_printed = false;
3331 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop);
3332
3333 // Very noisy: only enable this call if you are trying to determine
3334 // that a specific class gets found by this routine.
3335 // RC_TRACE macro has an embedded ResourceMark
3336 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
3337 // ("adjust check: name=%s", k->external_name()));
3338 // trace_name_printed = true;
3339
3340 // If the class being redefined is java.lang.Object, we need to fix all
3341 // array class vtables also
3342 if (k->is_array_klass() && _the_class_oop == SystemDictionary::Object_klass()) {
3343 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3344
3345 } else if (k->is_instance_klass()) {
3346 HandleMark hm(_thread);
3347 InstanceKlass *ik = InstanceKlass::cast(k);
3348
3349 // HotSpot specific optimization! HotSpot does not currently
3350 // support delegation from the bootstrap class loader to a
3351 // user-defined class loader. This means that if the bootstrap
3352 // class loader is the initiating class loader, then it will also
3353 // be the defining class loader. This also means that classes
3354 // loaded by the bootstrap class loader cannot refer to classes
3355 // loaded by a user-defined class loader. Note: a user-defined
3356 // class loader can delegate to the bootstrap class loader.
3357 //
3358 // If the current class being redefined has a user-defined class
3359 // loader as its defining class loader, then we can skip all
3360 // classes loaded by the bootstrap class loader.
3361 bool is_user_defined =
3362 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
3363 if (is_user_defined && ik->class_loader() == NULL) {
3364 return;
3365 }
3366
3367 // Fix the vtable embedded in the_class and subclasses of the_class,
3368 // if one exists. We discard scratch_class and we don't keep an
3369 // InstanceKlass around to hold obsolete methods so we don't have
3370 // any other InstanceKlass embedded vtables to update. The vtable
3371 // holds the Method*s for virtual (but not final) methods.
3372 // Default methods, or concrete methods in interfaces are stored
3373 // in the vtable, so if an interface changes we need to check
3374 // adjust_method_entries() for every InstanceKlass, which will also
3375 // adjust the default method vtable indices.
3376 // We also need to adjust any default method entries that are
3377 // not yet in the vtable, because the vtable setup is in progress.
3378 // This must be done after we adjust the default_methods and
3379 // default_vtable_indices for methods already in the vtable.
3380 // If redefining Unsafe, walk all the vtables looking for entries.
3381 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
3382 || _the_class_oop == SystemDictionary::internal_Unsafe_klass()
3383 || ik->is_subtype_of(_the_class_oop))) {
3384 // ik->vtable() creates a wrapper object; rm cleans it up
3385 ResourceMark rm(_thread);
3386
3387 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3388 ik->adjust_default_methods(the_class, &trace_name_printed);
3389 }
3390
3391 // If the current class has an itable and we are either redefining an
3392 // interface or if the current class is a subclass of the_class, then
3393 // we potentially have to fix the itable. If we are redefining an
3394 // interface, then we have to call adjust_method_entries() for
3395 // every InstanceKlass that has an itable since there isn't a
3396 // subclass relationship between an interface and an InstanceKlass.
3397 // If redefining Unsafe, walk all the itables looking for entries.
3398 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
3399 || _the_class_oop == SystemDictionary::internal_Unsafe_klass()
3400 || ik->is_subclass_of(_the_class_oop))) {
3401 // ik->itable() creates a wrapper object; rm cleans it up
3402 ResourceMark rm(_thread);
3403
3404 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3405 }
3406
3407 // The constant pools in other classes (other_cp) can refer to
3408 // methods in the_class. We have to update method information in
3409 // other_cp's cache. If other_cp has a previous version, then we
3410 // have to repeat the process for each previous version. The
3411 // constant pool cache holds the Method*s for non-virtual
3412 // methods and for virtual, final methods.
3413 //
3414 // Special case: if the current class is the_class, then new_cp
3415 // has already been attached to the_class and old_cp has already
3416 // been added as a previous version. The new_cp doesn't have any
3417 // cached references to old methods so it doesn't need to be
3418 // updated. We can simply start with the previous version(s) in
3419 // that case.
3420 constantPoolHandle other_cp;
3421 ConstantPoolCache* cp_cache;
3422
3423 if (ik != _the_class_oop) {
3424 // this klass' constant pool cache may need adjustment
3425 other_cp = constantPoolHandle(ik->constants());
3426 cp_cache = other_cp->cache();
3427 if (cp_cache != NULL) {
3428 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3429 }
3430 }
3431
3432 // the previous versions' constant pool caches may need adjustment
3433 for (InstanceKlass* pv_node = ik->previous_versions();
3434 pv_node != NULL;
3435 pv_node = pv_node->previous_versions()) {
3436 cp_cache = pv_node->constants()->cache();
3437 if (cp_cache != NULL) {
3438 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3439 }
3440 }
3441 }
3442 }
3443
3444 // Clean method data for this class
3445 void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) {
3446 if (k->is_instance_klass()) {
3447 InstanceKlass *ik = InstanceKlass::cast(k);
3448 // Clean MethodData of this class's methods so they don't refer to
3449 // old methods that are no longer running.
3450 Array<Method*>* methods = ik->methods();
3451 int num_methods = methods->length();
3452 for (int index = 0; index < num_methods; ++index) {
3453 if (methods->at(index)->method_data() != NULL) {
3454 methods->at(index)->method_data()->clean_weak_method_links();
3455 }
3456 }
3457 }
3458 }
3459
3460 void VM_RedefineClasses::update_jmethod_ids() {
3461 for (int j = 0; j < _matching_methods_length; ++j) {
3462 Method* old_method = _matching_old_methods[j];
3463 jmethodID jmid = old_method->find_jmethod_id_or_null();
3464 if (jmid != NULL) {
3465 // There is a jmethodID, change it to point to the new method
3466 methodHandle new_method_h(_matching_new_methods[j]);
3467 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3468 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3469 "should be replaced");
3470 }
3471 }
3472 }
3473
3474 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3475 int emcp_method_count = 0;
3476 int obsolete_count = 0;
3477 int old_index = 0;
3478 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3479 Method* old_method = _matching_old_methods[j];
3480 Method* new_method = _matching_new_methods[j];
3481 Method* old_array_method;
3482
3483 // Maintain an old_index into the _old_methods array by skipping
3484 // deleted methods
3485 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3486 ++old_index;
3487 }
3488
3489 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3490 // The EMCP definition from JSR-163 requires the bytecodes to be
3491 // the same with the exception of constant pool indices which may
3492 // differ. However, the constants referred to by those indices
3493 // must be the same.
3494 //
3495 // We use methods_EMCP() for comparison since constant pool
3496 // merging can remove duplicate constant pool entries that were
3497 // present in the old method and removed from the rewritten new
3498 // method. A faster binary comparison function would consider the
3499 // old and new methods to be different when they are actually
3500 // EMCP.
3501 //
3502 // The old and new methods are EMCP and you would think that we
3503 // could get rid of one of them here and now and save some space.
3504 // However, the concept of EMCP only considers the bytecodes and
3505 // the constant pool entries in the comparison. Other things,
3506 // e.g., the line number table (LNT) or the local variable table
3507 // (LVT) don't count in the comparison. So the new (and EMCP)
3508 // method can have a new LNT that we need so we can't just
3509 // overwrite the new method with the old method.
3510 //
3511 // When this routine is called, we have already attached the new
3512 // methods to the_class so the old methods are effectively
3513 // overwritten. However, if an old method is still executing,
3514 // then the old method cannot be collected until sometime after
3515 // the old method call has returned. So the overwriting of old
3516 // methods by new methods will save us space except for those
3517 // (hopefully few) old methods that are still executing.
3518 //
3519 // A method refers to a ConstMethod* and this presents another
3520 // possible avenue to space savings. The ConstMethod* in the
3521 // new method contains possibly new attributes (LNT, LVT, etc).
3522 // At first glance, it seems possible to save space by replacing
3523 // the ConstMethod* in the old method with the ConstMethod*
3524 // from the new method. The old and new methods would share the
3525 // same ConstMethod* and we would save the space occupied by
3526 // the old ConstMethod*. However, the ConstMethod* contains
3527 // a back reference to the containing method. Sharing the
3528 // ConstMethod* between two methods could lead to confusion in
3529 // the code that uses the back reference. This would lead to
3530 // brittle code that could be broken in non-obvious ways now or
3531 // in the future.
3532 //
3533 // Another possibility is to copy the ConstMethod* from the new
3534 // method to the old method and then overwrite the new method with
3535 // the old method. Since the ConstMethod* contains the bytecodes
3536 // for the method embedded in the oop, this option would change
3537 // the bytecodes out from under any threads executing the old
3538 // method and make the thread's bcp invalid. Since EMCP requires
3539 // that the bytecodes be the same modulo constant pool indices, it
3540 // is straight forward to compute the correct new bcp in the new
3541 // ConstMethod* from the old bcp in the old ConstMethod*. The
3542 // time consuming part would be searching all the frames in all
3543 // of the threads to find all of the calls to the old method.
3544 //
3545 // It looks like we will have to live with the limited savings
3546 // that we get from effectively overwriting the old methods
3547 // when the new methods are attached to the_class.
3548
3549 // Count number of methods that are EMCP. The method will be marked
3550 // old but not obsolete if it is EMCP.
3551 emcp_method_count++;
3552
3553 // An EMCP method is _not_ obsolete. An obsolete method has a
3554 // different jmethodID than the current method. An EMCP method
3555 // has the same jmethodID as the current method. Having the
3556 // same jmethodID for all EMCP versions of a method allows for
3557 // a consistent view of the EMCP methods regardless of which
3558 // EMCP method you happen to have in hand. For example, a
3559 // breakpoint set in one EMCP method will work for all EMCP
3560 // versions of the method including the current one.
3561 } else {
3562 // mark obsolete methods as such
3563 old_method->set_is_obsolete();
3564 obsolete_count++;
3565
3566 // obsolete methods need a unique idnum so they become new entries in
3567 // the jmethodID cache in InstanceKlass
3568 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3569 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
3570 if (num != ConstMethod::UNSET_IDNUM) {
3571 old_method->set_method_idnum(num);
3572 }
3573
3574 // With tracing we try not to "yack" too much. The position of
3575 // this trace assumes there are fewer obsolete methods than
3576 // EMCP methods.
3577 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
3578 old_method->name()->as_C_string(),
3579 old_method->signature()->as_C_string()));
3580 }
3581 old_method->set_is_old();
3582 }
3583 for (int i = 0; i < _deleted_methods_length; ++i) {
3584 Method* old_method = _deleted_methods[i];
3585
3586 assert(!old_method->has_vtable_index(),
3587 "cannot delete methods with vtable entries");;
3588
3589 // Mark all deleted methods as old, obsolete and deleted
3590 old_method->set_is_deleted();
3591 old_method->set_is_old();
3592 old_method->set_is_obsolete();
3593 ++obsolete_count;
3594 // With tracing we try not to "yack" too much. The position of
3595 // this trace assumes there are fewer obsolete methods than
3596 // EMCP methods.
3597 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
3598 old_method->name()->as_C_string(),
3599 old_method->signature()->as_C_string()));
3600 }
3601 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3602 "sanity check");
3603 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count,
3604 obsolete_count));
3605 return emcp_method_count;
3606 }
3607
3608 // This internal class transfers the native function registration from old methods
3609 // to new methods. It is designed to handle both the simple case of unchanged
3610 // native methods and the complex cases of native method prefixes being added and/or
3611 // removed.
3612 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3613 //
3614 // This class is used after the new methods have been installed in "the_class".
3615 //
3616 // So, for example, the following must be handled. Where 'm' is a method and
3617 // a number followed by an underscore is a prefix.
3618 //
3619 // Old Name New Name
3620 // Simple transfer to new method m -> m
3621 // Add prefix m -> 1_m
3622 // Remove prefix 1_m -> m
3623 // Simultaneous add of prefixes m -> 3_2_1_m
3624 // Simultaneous removal of prefixes 3_2_1_m -> m
3625 // Simultaneous add and remove 1_m -> 2_m
3626 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3627 //
3628 class TransferNativeFunctionRegistration {
3629 private:
3630 instanceKlassHandle the_class;
3631 int prefix_count;
3632 char** prefixes;
3633
3634 // Recursively search the binary tree of possibly prefixed method names.
3635 // Iteration could be used if all agents were well behaved. Full tree walk is
3636 // more resilent to agents not cleaning up intermediate methods.
3637 // Branch at each depth in the binary tree is:
3638 // (1) without the prefix.
3639 // (2) with the prefix.
3640 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3641 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3642 Symbol* signature) {
3643 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3644 if (name_symbol != NULL) {
3645 Method* method = the_class()->lookup_method(name_symbol, signature);
3646 if (method != NULL) {
3647 // Even if prefixed, intermediate methods must exist.
3648 if (method->is_native()) {
3649 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3650 return method;
3651 }
3652 if (depth < prefix_count) {
3653 // Try applying further prefixes (other than this one).
3654 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3655 if (method != NULL) {
3656 return method; // found
3657 }
3658
3659 // Try adding this prefix to the method name and see if it matches
3660 // another method name.
3661 char* prefix = prefixes[depth];
3662 size_t prefix_len = strlen(prefix);
3663 size_t trial_len = name_len + prefix_len;
3664 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3665 strcpy(trial_name_str, prefix);
3666 strcat(trial_name_str, name_str);
3667 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3668 signature);
3669 if (method != NULL) {
3670 // If found along this branch, it was prefixed, mark as such
3671 method->set_is_prefixed_native();
3672 return method; // found
3673 }
3674 }
3675 }
3676 }
3677 return NULL; // This whole branch bore nothing
3678 }
3679
3680 // Return the method name with old prefixes stripped away.
3681 char* method_name_without_prefixes(Method* method) {
3682 Symbol* name = method->name();
3683 char* name_str = name->as_utf8();
3684
3685 // Old prefixing may be defunct, strip prefixes, if any.
3686 for (int i = prefix_count-1; i >= 0; i--) {
3687 char* prefix = prefixes[i];
3688 size_t prefix_len = strlen(prefix);
3689 if (strncmp(prefix, name_str, prefix_len) == 0) {
3690 name_str += prefix_len;
3691 }
3692 }
3693 return name_str;
3694 }
3695
3696 // Strip any prefixes off the old native method, then try to find a
3697 // (possibly prefixed) new native that matches it.
3698 Method* strip_and_search_for_new_native(Method* method) {
3699 ResourceMark rm;
3700 char* name_str = method_name_without_prefixes(method);
3701 return search_prefix_name_space(0, name_str, strlen(name_str),
3702 method->signature());
3703 }
3704
3705 public:
3706
3707 // Construct a native method transfer processor for this class.
3708 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3709 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3710
3711 the_class = _the_class;
3712 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3713 }
3714
3715 // Attempt to transfer any of the old or deleted methods that are native
3716 void transfer_registrations(Method** old_methods, int methods_length) {
3717 for (int j = 0; j < methods_length; j++) {
3718 Method* old_method = old_methods[j];
3719
3720 if (old_method->is_native() && old_method->has_native_function()) {
3721 Method* new_method = strip_and_search_for_new_native(old_method);
3722 if (new_method != NULL) {
3723 // Actually set the native function in the new method.
3724 // Redefine does not send events (except CFLH), certainly not this
3725 // behind the scenes re-registration.
3726 new_method->set_native_function(old_method->native_function(),
3727 !Method::native_bind_event_is_interesting);
3728 }
3729 }
3730 }
3731 }
3732 };
3733
3734 // Don't lose the association between a native method and its JNI function.
3735 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3736 TransferNativeFunctionRegistration transfer(the_class);
3737 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3738 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3739 }
3740
3741 // Deoptimize all compiled code that depends on this class.
3742 //
3743 // If the can_redefine_classes capability is obtained in the onload
3744 // phase then the compiler has recorded all dependencies from startup.
3745 // In that case we need only deoptimize and throw away all compiled code
3746 // that depends on the class.
3747 //
3748 // If can_redefine_classes is obtained sometime after the onload
3749 // phase then the dependency information may be incomplete. In that case
3750 // the first call to RedefineClasses causes all compiled code to be
3751 // thrown away. As can_redefine_classes has been obtained then
3752 // all future compilations will record dependencies so second and
3753 // subsequent calls to RedefineClasses need only throw away code
3754 // that depends on the class.
3755 //
3756 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3757 assert_locked_or_safepoint(Compile_lock);
3758
3759 // All dependencies have been recorded from startup or this is a second or
3760 // subsequent use of RedefineClasses
3761 if (JvmtiExport::all_dependencies_are_recorded()) {
3762 CodeCache::flush_evol_dependents_on(k_h);
3763 } else {
3764 CodeCache::mark_all_nmethods_for_deoptimization();
3765
3766 ResourceMark rm(THREAD);
3767 DeoptimizationMarker dm;
3768
3769 // Deoptimize all activations depending on marked nmethods
3770 Deoptimization::deoptimize_dependents();
3771
3772 // Make the dependent methods not entrant
3773 CodeCache::make_marked_nmethods_not_entrant();
3774
3775 // From now on we know that the dependency information is complete
3776 JvmtiExport::set_all_dependencies_are_recorded(true);
3777 }
3778 }
3779
3780 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3781 Method* old_method;
3782 Method* new_method;
3783
3784 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3785 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3786 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3787 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3788
3789 _matching_methods_length = 0;
3790 _deleted_methods_length = 0;
3791 _added_methods_length = 0;
3792
3793 int nj = 0;
3794 int oj = 0;
3795 while (true) {
3796 if (oj >= _old_methods->length()) {
3797 if (nj >= _new_methods->length()) {
3798 break; // we've looked at everything, done
3799 }
3800 // New method at the end
3801 new_method = _new_methods->at(nj);
3802 _added_methods[_added_methods_length++] = new_method;
3803 ++nj;
3804 } else if (nj >= _new_methods->length()) {
3805 // Old method, at the end, is deleted
3806 old_method = _old_methods->at(oj);
3807 _deleted_methods[_deleted_methods_length++] = old_method;
3808 ++oj;
3809 } else {
3810 old_method = _old_methods->at(oj);
3811 new_method = _new_methods->at(nj);
3812 if (old_method->name() == new_method->name()) {
3813 if (old_method->signature() == new_method->signature()) {
3814 _matching_old_methods[_matching_methods_length ] = old_method;
3815 _matching_new_methods[_matching_methods_length++] = new_method;
3816 ++nj;
3817 ++oj;
3818 } else {
3819 // added overloaded have already been moved to the end,
3820 // so this is a deleted overloaded method
3821 _deleted_methods[_deleted_methods_length++] = old_method;
3822 ++oj;
3823 }
3824 } else { // names don't match
3825 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3826 // new method
3827 _added_methods[_added_methods_length++] = new_method;
3828 ++nj;
3829 } else {
3830 // deleted method
3831 _deleted_methods[_deleted_methods_length++] = old_method;
3832 ++oj;
3833 }
3834 }
3835 }
3836 }
3837 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3838 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3839 }
3840
3841
3842 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3843 instanceKlassHandle scratch_class) {
3844 // Swap annotation fields values
3845 Annotations* old_annotations = the_class->annotations();
3846 the_class->set_annotations(scratch_class->annotations());
3847 scratch_class->set_annotations(old_annotations);
3848 }
3849
3850
3851 // Install the redefinition of a class:
3852 // - house keeping (flushing breakpoints and caches, deoptimizing
3853 // dependent compiled code)
3854 // - replacing parts in the_class with parts from scratch_class
3855 // - adding a weak reference to track the obsolete but interesting
3856 // parts of the_class
3857 // - adjusting constant pool caches and vtables in other classes
3858 // that refer to methods in the_class. These adjustments use the
3859 // ClassLoaderDataGraph::classes_do() facility which only allows
3860 // a helper method to be specified. The interesting parameters
3861 // that we would like to pass to the helper method are saved in
3862 // static global fields in the VM operation.
3863 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3864 Klass* scratch_class_oop, TRAPS) {
3865
3866 HandleMark hm(THREAD); // make sure handles from this call are freed
3867 RC_TIMER_START(_timer_rsc_phase1);
3868
3869 instanceKlassHandle scratch_class(scratch_class_oop);
3870
3871 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3872 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3873 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3874
3875 // Remove all breakpoints in methods of this class
3876 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3877 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3878
3879 // Deoptimize all compiled code that depends on this class
3880 flush_dependent_code(the_class, THREAD);
3881
3882 _old_methods = the_class->methods();
3883 _new_methods = scratch_class->methods();
3884 _the_class_oop = the_class_oop;
3885 compute_added_deleted_matching_methods();
3886 update_jmethod_ids();
3887
3888 // Attach new constant pool to the original klass. The original
3889 // klass still refers to the old constant pool (for now).
3890 scratch_class->constants()->set_pool_holder(the_class());
3891
3892 #if 0
3893 // In theory, with constant pool merging in place we should be able
3894 // to save space by using the new, merged constant pool in place of
3895 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3896 // the klass version we are replacing now and any constant pool(s) in
3897 // previous versions of klass. Nice theory, doesn't work in practice.
3898 // When this code is enabled, even simple programs throw NullPointer
3899 // exceptions. I'm guessing that this is caused by some constant pool
3900 // cache difference between the new, merged constant pool and the
3901 // constant pool that was just being used by the klass. I'm keeping
3902 // this code around to archive the idea, but the code has to remain
3903 // disabled for now.
3904
3905 // Attach each old method to the new constant pool. This can be
3906 // done here since we are past the bytecode verification and
3907 // constant pool optimization phases.
3908 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3909 Method* method = _old_methods->at(i);
3910 method->set_constants(scratch_class->constants());
3911 }
3912
3913 {
3914 // walk all previous versions of the klass
3915 InstanceKlass *ik = (InstanceKlass *)the_class();
3916 PreviousVersionWalker pvw(ik);
3917 instanceKlassHandle ikh;
3918 do {
3919 ikh = pvw.next_previous_version();
3920 if (!ikh.is_null()) {
3921 ik = ikh();
3922
3923 // attach previous version of klass to the new constant pool
3924 ik->set_constants(scratch_class->constants());
3925
3926 // Attach each method in the previous version of klass to the
3927 // new constant pool
3928 Array<Method*>* prev_methods = ik->methods();
3929 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3930 Method* method = prev_methods->at(i);
3931 method->set_constants(scratch_class->constants());
3932 }
3933 }
3934 } while (!ikh.is_null());
3935 }
3936 #endif
3937
3938 // Replace methods and constantpool
3939 the_class->set_methods(_new_methods);
3940 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3941 // and to be able to undo operation easily.
3942
3943 Array<int>* old_ordering = the_class->method_ordering();
3944 the_class->set_method_ordering(scratch_class->method_ordering());
3945 scratch_class->set_method_ordering(old_ordering);
3946
3947 ConstantPool* old_constants = the_class->constants();
3948 the_class->set_constants(scratch_class->constants());
3949 scratch_class->set_constants(old_constants); // See the previous comment.
3950 #if 0
3951 // We are swapping the guts of "the new class" with the guts of "the
3952 // class". Since the old constant pool has just been attached to "the
3953 // new class", it seems logical to set the pool holder in the old
3954 // constant pool also. However, doing this will change the observable
3955 // class hierarchy for any old methods that are still executing. A
3956 // method can query the identity of its "holder" and this query uses
3957 // the method's constant pool link to find the holder. The change in
3958 // holding class from "the class" to "the new class" can confuse
3959 // things.
3960 //
3961 // Setting the old constant pool's holder will also cause
3962 // verification done during vtable initialization below to fail.
3963 // During vtable initialization, the vtable's class is verified to be
3964 // a subtype of the method's holder. The vtable's class is "the
3965 // class" and the method's holder is gotten from the constant pool
3966 // link in the method itself. For "the class"'s directly implemented
3967 // methods, the method holder is "the class" itself (as gotten from
3968 // the new constant pool). The check works fine in this case. The
3969 // check also works fine for methods inherited from super classes.
3970 //
3971 // Miranda methods are a little more complicated. A miranda method is
3972 // provided by an interface when the class implementing the interface
3973 // does not provide its own method. These interfaces are implemented
3974 // internally as an InstanceKlass. These special instanceKlasses
3975 // share the constant pool of the class that "implements" the
3976 // interface. By sharing the constant pool, the method holder of a
3977 // miranda method is the class that "implements" the interface. In a
3978 // non-redefine situation, the subtype check works fine. However, if
3979 // the old constant pool's pool holder is modified, then the check
3980 // fails because there is no class hierarchy relationship between the
3981 // vtable's class and "the new class".
3982
3983 old_constants->set_pool_holder(scratch_class());
3984 #endif
3985
3986 // track number of methods that are EMCP for add_previous_version() call below
3987 int emcp_method_count = check_methods_and_mark_as_obsolete();
3988 transfer_old_native_function_registrations(the_class);
3989
3990 // The class file bytes from before any retransformable agents mucked
3991 // with them was cached on the scratch class, move to the_class.
3992 // Note: we still want to do this if nothing needed caching since it
3993 // should get cleared in the_class too.
3994 if (the_class->get_cached_class_file_bytes() == 0) {
3995 // the_class doesn't have a cache yet so copy it
3996 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3997 }
3998 else if (scratch_class->get_cached_class_file_bytes() !=
3999 the_class->get_cached_class_file_bytes()) {
4000 // The same class can be present twice in the scratch classes list or there
4001 // are multiple concurrent RetransformClasses calls on different threads.
4002 // In such cases we have to deallocate scratch_class cached_class_file.
4003 os::free(scratch_class->get_cached_class_file());
4004 }
4005
4006 // NULL out in scratch class to not delete twice. The class to be redefined
4007 // always owns these bytes.
4008 scratch_class->set_cached_class_file(NULL);
4009
4010 // Replace inner_classes
4011 Array<u2>* old_inner_classes = the_class->inner_classes();
4012 the_class->set_inner_classes(scratch_class->inner_classes());
4013 scratch_class->set_inner_classes(old_inner_classes);
4014
4015 // Initialize the vtable and interface table after
4016 // methods have been rewritten
4017 {
4018 ResourceMark rm(THREAD);
4019 // no exception should happen here since we explicitly
4020 // do not check loader constraints.
4021 // compare_and_normalize_class_versions has already checked:
4022 // - classloaders unchanged, signatures unchanged
4023 // - all instanceKlasses for redefined classes reused & contents updated
4024 the_class->vtable()->initialize_vtable(false, THREAD);
4025 the_class->itable()->initialize_itable(false, THREAD);
4026 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4027 }
4028
4029 // Leave arrays of jmethodIDs and itable index cache unchanged
4030
4031 // Copy the "source file name" attribute from new class version
4032 the_class->set_source_file_name_index(
4033 scratch_class->source_file_name_index());
4034
4035 // Copy the "source debug extension" attribute from new class version
4036 the_class->set_source_debug_extension(
4037 scratch_class->source_debug_extension(),
4038 scratch_class->source_debug_extension() == NULL ? 0 :
4039 (int)strlen(scratch_class->source_debug_extension()));
4040
4041 // Use of javac -g could be different in the old and the new
4042 if (scratch_class->access_flags().has_localvariable_table() !=
4043 the_class->access_flags().has_localvariable_table()) {
4044
4045 AccessFlags flags = the_class->access_flags();
4046 if (scratch_class->access_flags().has_localvariable_table()) {
4047 flags.set_has_localvariable_table();
4048 } else {
4049 flags.clear_has_localvariable_table();
4050 }
4051 the_class->set_access_flags(flags);
4052 }
4053
4054 swap_annotations(the_class, scratch_class);
4055
4056 // Replace minor version number of class file
4057 u2 old_minor_version = the_class->minor_version();
4058 the_class->set_minor_version(scratch_class->minor_version());
4059 scratch_class->set_minor_version(old_minor_version);
4060
4061 // Replace major version number of class file
4062 u2 old_major_version = the_class->major_version();
4063 the_class->set_major_version(scratch_class->major_version());
4064 scratch_class->set_major_version(old_major_version);
4065
4066 // Replace CP indexes for class and name+type of enclosing method
4067 u2 old_class_idx = the_class->enclosing_method_class_index();
4068 u2 old_method_idx = the_class->enclosing_method_method_index();
4069 the_class->set_enclosing_method_indices(
4070 scratch_class->enclosing_method_class_index(),
4071 scratch_class->enclosing_method_method_index());
4072 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4073
4074 the_class->set_has_been_redefined();
4075
4076 // keep track of previous versions of this class
4077 the_class->add_previous_version(scratch_class, emcp_method_count);
4078
4079 RC_TIMER_STOP(_timer_rsc_phase1);
4080 RC_TIMER_START(_timer_rsc_phase2);
4081
4082 // Adjust constantpool caches and vtables for all classes
4083 // that reference methods of the evolved class.
4084 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4085 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4086
4087 // JSR-292 support
4088 MemberNameTable* mnt = the_class->member_names();
4089 if (mnt != NULL) {
4090 bool trace_name_printed = false;
4091 mnt->adjust_method_entries(the_class(), &trace_name_printed);
4092 }
4093
4094 if (the_class->oop_map_cache() != NULL) {
4095 // Flush references to any obsolete methods from the oop map cache
4096 // so that obsolete methods are not pinned.
4097 the_class->oop_map_cache()->flush_obsolete_entries();
4098 }
4099
4100 // increment the classRedefinedCount field in the_class and in any
4101 // direct and indirect subclasses of the_class
4102 increment_class_counter((InstanceKlass *)the_class(), THREAD);
4103
4104 // RC_TRACE macro has an embedded ResourceMark
4105 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
4106 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4107 the_class->external_name(),
4108 java_lang_Class::classRedefinedCount(the_class_mirror),
4109 os::available_memory() >> 10));
4110
4111 {
4112 ResourceMark rm(THREAD);
4113 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4114 the_class->external_name(),
4115 java_lang_Class::classRedefinedCount(the_class_mirror));
4116
4117 }
4118 RC_TIMER_STOP(_timer_rsc_phase2);
4119 } // end redefine_single_class()
4120
4121
4122 // Increment the classRedefinedCount field in the specific InstanceKlass
4123 // and in all direct and indirect subclasses.
4124 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4125 oop class_mirror = ik->java_mirror();
4126 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4127 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4128 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4129
4130 if (class_oop != _the_class_oop) {
4131 // _the_class_oop count is printed at end of redefine_single_class()
4132 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
4133 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
4134 }
4135
4136 for (Klass *subk = ik->subklass(); subk != NULL;
4137 subk = subk->next_sibling()) {
4138 if (subk->is_instance_klass()) {
4139 // Only update instanceKlasses
4140 InstanceKlass *subik = InstanceKlass::cast(subk);
4141 // recursively do subclasses of the current subclass
4142 increment_class_counter(subik, THREAD);
4143 }
4144 }
4145 }
4146
4147 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4148 bool no_old_methods = true; // be optimistic
4149
4150 // Both array and instance classes have vtables.
4151 // a vtable should never contain old or obsolete methods
4152 ResourceMark rm(_thread);
4153 if (k->vtable_length() > 0 &&
4154 !k->vtable()->check_no_old_or_obsolete_entries()) {
4155 if (RC_TRACE_ENABLED(0x00004000)) {
4156 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4157 ("klassVtable::check_no_old_or_obsolete_entries failure"
4158 " -- OLD or OBSOLETE method found -- class: %s",
4159 k->signature_name()));
4160 k->vtable()->dump_vtable();
4161 }
4162 no_old_methods = false;
4163 }
4164
4165 if (k->is_instance_klass()) {
4166 HandleMark hm(_thread);
4167 InstanceKlass *ik = InstanceKlass::cast(k);
4168
4169 // an itable should never contain old or obsolete methods
4170 if (ik->itable_length() > 0 &&
4171 !ik->itable()->check_no_old_or_obsolete_entries()) {
4172 if (RC_TRACE_ENABLED(0x00004000)) {
4173 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4174 ("klassItable::check_no_old_or_obsolete_entries failure"
4175 " -- OLD or OBSOLETE method found -- class: %s",
4176 ik->signature_name()));
4177 ik->itable()->dump_itable();
4178 }
4179 no_old_methods = false;
4180 }
4181
4182 // the constant pool cache should never contain non-deleted old or obsolete methods
4183 if (ik->constants() != NULL &&
4184 ik->constants()->cache() != NULL &&
4185 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4186 if (RC_TRACE_ENABLED(0x00004000)) {
4187 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4188 ("cp-cache::check_no_old_or_obsolete_entries failure"
4189 " -- OLD or OBSOLETE method found -- class: %s",
4190 ik->signature_name()));
4191 ik->constants()->cache()->dump_cache();
4192 }
4193 no_old_methods = false;
4194 }
4195 }
4196
4197 // print and fail guarantee if old methods are found.
4198 if (!no_old_methods) {
4199 if (RC_TRACE_ENABLED(0x00004000)) {
4200 dump_methods();
4201 } else {
4202 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
4203 "to see more info about the following guarantee() failure.");
4204 }
4205 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4206 }
4207 }
4208
4209
4210 void VM_RedefineClasses::dump_methods() {
4211 int j;
4212 RC_TRACE(0x00004000, ("_old_methods --"));
4213 for (j = 0; j < _old_methods->length(); ++j) {
4214 Method* m = _old_methods->at(j);
4215 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4216 m->access_flags().print_on(tty);
4217 tty->print(" -- ");
4218 m->print_name(tty);
4219 tty->cr();
4220 }
4221 RC_TRACE(0x00004000, ("_new_methods --"));
4222 for (j = 0; j < _new_methods->length(); ++j) {
4223 Method* m = _new_methods->at(j);
4224 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4225 m->access_flags().print_on(tty);
4226 tty->print(" -- ");
4227 m->print_name(tty);
4228 tty->cr();
4229 }
4230 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
4231 for (j = 0; j < _matching_methods_length; ++j) {
4232 Method* m = _matching_old_methods[j];
4233 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4234 m->access_flags().print_on(tty);
4235 tty->print(" -- ");
4236 m->print_name(tty);
4237 tty->cr();
4238 m = _matching_new_methods[j];
4239 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
4240 m->access_flags().print_on(tty);
4241 tty->cr();
4242 }
4243 RC_TRACE(0x00004000, ("_deleted_methods --"));
4244 for (j = 0; j < _deleted_methods_length; ++j) {
4245 Method* m = _deleted_methods[j];
4246 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4247 m->access_flags().print_on(tty);
4248 tty->print(" -- ");
4249 m->print_name(tty);
4250 tty->cr();
4251 }
4252 RC_TRACE(0x00004000, ("_added_methods --"));
4253 for (j = 0; j < _added_methods_length; ++j) {
4254 Method* m = _added_methods[j];
4255 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4256 m->access_flags().print_on(tty);
4257 tty->print(" -- ");
4258 m->print_name(tty);
4259 tty->cr();
4260 }
4261 }
4262
4263 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4264 VM_Operation::print_on_error(st);
4265 if (_the_class_oop != NULL) {
4266 ResourceMark rm;
4267 st->print_cr(", redefining class %s", _the_class_oop->external_name());
4268 }
4269 }