1 /*
2 * Copyright (c) 2003, 2014, 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/metadataOnStackMark.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "interpreter/oopMapCache.hpp"
32 #include "interpreter/rewriter.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/klassVtable.hpp"
39 #include "prims/jvmtiImpl.hpp"
40 #include "prims/jvmtiRedefineClasses.hpp"
41 #include "prims/methodComparator.hpp"
42 #include "runtime/deoptimization.hpp"
43 #include "runtime/relocator.hpp"
44 #include "utilities/bitMap.inline.hpp"
45
46 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
47
48 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
49 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
50 Method** VM_RedefineClasses::_matching_old_methods = NULL;
51 Method** VM_RedefineClasses::_matching_new_methods = NULL;
52 Method** VM_RedefineClasses::_deleted_methods = NULL;
53 Method** VM_RedefineClasses::_added_methods = NULL;
54 int VM_RedefineClasses::_matching_methods_length = 0;
55 int VM_RedefineClasses::_deleted_methods_length = 0;
56 int VM_RedefineClasses::_added_methods_length = 0;
57 Klass* VM_RedefineClasses::_the_class_oop = NULL;
58
59
60 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
61 const jvmtiClassDefinition *class_defs,
62 JvmtiClassLoadKind class_load_kind) {
63 _class_count = class_count;
64 _class_defs = class_defs;
65 _class_load_kind = class_load_kind;
66 _res = JVMTI_ERROR_NONE;
67 }
68
69 bool VM_RedefineClasses::doit_prologue() {
70 if (_class_count == 0) {
71 _res = JVMTI_ERROR_NONE;
72 return false;
73 }
74 if (_class_defs == NULL) {
75 _res = JVMTI_ERROR_NULL_POINTER;
76 return false;
77 }
78 for (int i = 0; i < _class_count; i++) {
79 if (_class_defs[i].klass == NULL) {
80 _res = JVMTI_ERROR_INVALID_CLASS;
81 return false;
82 }
83 if (_class_defs[i].class_byte_count == 0) {
84 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
85 return false;
86 }
87 if (_class_defs[i].class_bytes == NULL) {
88 _res = JVMTI_ERROR_NULL_POINTER;
89 return false;
90 }
91 }
92
93 // Start timer after all the sanity checks; not quite accurate, but
94 // better than adding a bunch of stop() calls.
95 RC_TIMER_START(_timer_vm_op_prologue);
96
97 // We first load new class versions in the prologue, because somewhere down the
98 // call chain it is required that the current thread is a Java thread.
99 _res = load_new_class_versions(Thread::current());
100 if (_res != JVMTI_ERROR_NONE) {
101 // free any successfully created classes, since none are redefined
102 for (int i = 0; i < _class_count; i++) {
103 if (_scratch_classes[i] != NULL) {
104 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
105 // Free the memory for this class at class unloading time. Not before
106 // because CMS might think this is still live.
107 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
108 }
109 }
110 // Free os::malloc allocated memory in load_new_class_version.
111 os::free(_scratch_classes);
112 RC_TIMER_STOP(_timer_vm_op_prologue);
113 return false;
114 }
115
116 RC_TIMER_STOP(_timer_vm_op_prologue);
117 return true;
118 }
119
120 void VM_RedefineClasses::doit() {
121 Thread *thread = Thread::current();
122
123 if (UseSharedSpaces) {
124 // Sharing is enabled so we remap the shared readonly space to
125 // shared readwrite, private just in case we need to redefine
126 // a shared class. We do the remap during the doit() phase of
127 // the safepoint to be safer.
128 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
129 RC_TRACE_WITH_THREAD(0x00000001, thread,
130 ("failed to remap shared readonly space to readwrite, private"));
131 _res = JVMTI_ERROR_INTERNAL;
132 return;
133 }
134 }
135
136 // Mark methods seen on stack and everywhere else so old methods are not
137 // cleaned up if they're on the stack.
138 MetadataOnStackMark md_on_stack(true);
139 HandleMark hm(thread); // make sure any handles created are deleted
140 // before the stack walk again.
141
142 for (int i = 0; i < _class_count; i++) {
143 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
144 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
145 // Free the memory for this class at class unloading time. Not before
146 // because CMS might think this is still live.
147 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
148 _scratch_classes[i] = NULL;
149 }
150
151 // Disable any dependent concurrent compilations
152 SystemDictionary::notice_modification();
153
154 // Set flag indicating that some invariants are no longer true.
155 // See jvmtiExport.hpp for detailed explanation.
156 JvmtiExport::set_has_redefined_a_class();
157
158 // check_class() is optionally called for product bits, but is
159 // always called for non-product bits.
160 #ifdef PRODUCT
161 if (RC_TRACE_ENABLED(0x00004000)) {
162 #endif
163 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
164 CheckClass check_class(thread);
165 ClassLoaderDataGraph::classes_do(&check_class);
166 #ifdef PRODUCT
167 }
168 #endif
169 }
170
171 void VM_RedefineClasses::doit_epilogue() {
172 // Free os::malloc allocated memory.
173 os::free(_scratch_classes);
174
175 if (RC_TRACE_ENABLED(0x00000004)) {
176 // Used to have separate timers for "doit" and "all", but the timer
177 // overhead skewed the measurements.
178 jlong doit_time = _timer_rsc_phase1.milliseconds() +
179 _timer_rsc_phase2.milliseconds();
180 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
181
182 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
183 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
184 _timer_vm_op_prologue.milliseconds(), doit_time));
185 RC_TRACE(0x00000004,
186 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
187 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
188 }
189 }
190
191 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
192 // classes for primitives cannot be redefined
193 if (java_lang_Class::is_primitive(klass_mirror)) {
194 return false;
195 }
196 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
197 // classes for arrays cannot be redefined
198 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
199 return false;
200 }
201 return true;
202 }
203
204 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
205 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
206 // direct CP entries, there is just the current entry to append. For
207 // indirect and double-indirect CP entries, there are zero or more
208 // referenced CP entries along with the current entry to append.
209 // Indirect and double-indirect CP entries are handled by recursive
210 // calls to append_entry() as needed. The referenced CP entries are
211 // always appended to *merge_cp_p before the referee CP entry. These
212 // referenced CP entries may already exist in *merge_cp_p in which case
213 // there is nothing extra to append and only the current entry is
214 // appended.
215 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
216 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
217 TRAPS) {
218
219 // append is different depending on entry tag type
220 switch (scratch_cp->tag_at(scratch_i).value()) {
221
222 // The old verifier is implemented outside the VM. It loads classes,
223 // but does not resolve constant pool entries directly so we never
224 // see Class entries here with the old verifier. Similarly the old
225 // verifier does not like Class entries in the input constant pool.
226 // The split-verifier is implemented in the VM so it can optionally
227 // and directly resolve constant pool entries to load classes. The
228 // split-verifier can accept either Class entries or UnresolvedClass
229 // entries in the input constant pool. We revert the appended copy
230 // back to UnresolvedClass so that either verifier will be happy
231 // with the constant pool entry.
232 case JVM_CONSTANT_Class:
233 {
234 // revert the copy to JVM_CONSTANT_UnresolvedClass
235 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
236 scratch_cp->klass_name_at(scratch_i));
237
238 if (scratch_i != *merge_cp_length_p) {
239 // The new entry in *merge_cp_p is at a different index than
240 // the new entry in scratch_cp so we need to map the index values.
241 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
242 }
243 (*merge_cp_length_p)++;
244 } break;
245
246 // these are direct CP entries so they can be directly appended,
247 // but double and long take two constant pool entries
248 case JVM_CONSTANT_Double: // fall through
249 case JVM_CONSTANT_Long:
250 {
251 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
252 THREAD);
253
254 if (scratch_i != *merge_cp_length_p) {
255 // The new entry in *merge_cp_p is at a different index than
256 // the new entry in scratch_cp so we need to map the index values.
257 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
258 }
259 (*merge_cp_length_p) += 2;
260 } break;
261
262 // these are direct CP entries so they can be directly appended
263 case JVM_CONSTANT_Float: // fall through
264 case JVM_CONSTANT_Integer: // fall through
265 case JVM_CONSTANT_Utf8: // fall through
266
267 // This was an indirect CP entry, but it has been changed into
268 // Symbol*s so this entry can be directly appended.
269 case JVM_CONSTANT_String: // fall through
270
271 // These were indirect CP entries, but they have been changed into
272 // Symbol*s so these entries can be directly appended.
273 case JVM_CONSTANT_UnresolvedClass: // fall through
274 {
275 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
276 THREAD);
277
278 if (scratch_i != *merge_cp_length_p) {
279 // The new entry in *merge_cp_p is at a different index than
280 // the new entry in scratch_cp so we need to map the index values.
281 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
282 }
283 (*merge_cp_length_p)++;
284 } break;
285
286 // this is an indirect CP entry so it needs special handling
287 case JVM_CONSTANT_NameAndType:
288 {
289 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
290 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
291 merge_cp_length_p, THREAD);
292
293 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
294 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
295 merge_cp_p, merge_cp_length_p,
296 THREAD);
297
298 // If the referenced entries already exist in *merge_cp_p, then
299 // both new_name_ref_i and new_signature_ref_i will both be 0.
300 // In that case, all we are appending is the current entry.
301 if (new_name_ref_i != name_ref_i) {
302 RC_TRACE(0x00080000,
303 ("NameAndType entry@%d name_ref_index change: %d to %d",
304 *merge_cp_length_p, name_ref_i, new_name_ref_i));
305 }
306 if (new_signature_ref_i != signature_ref_i) {
307 RC_TRACE(0x00080000,
308 ("NameAndType entry@%d signature_ref_index change: %d to %d",
309 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
310 }
311
312 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
313 new_name_ref_i, new_signature_ref_i);
314 if (scratch_i != *merge_cp_length_p) {
315 // The new entry in *merge_cp_p is at a different index than
316 // the new entry in scratch_cp so we need to map the index values.
317 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
318 }
319 (*merge_cp_length_p)++;
320 } break;
321
322 // this is a double-indirect CP entry so it needs special handling
323 case JVM_CONSTANT_Fieldref: // fall through
324 case JVM_CONSTANT_InterfaceMethodref: // fall through
325 case JVM_CONSTANT_Methodref:
326 {
327 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
328 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
329 merge_cp_p, merge_cp_length_p, THREAD);
330
331 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
332 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
333 merge_cp_p, merge_cp_length_p, THREAD);
334
335 const char *entry_name;
336 switch (scratch_cp->tag_at(scratch_i).value()) {
337 case JVM_CONSTANT_Fieldref:
338 entry_name = "Fieldref";
339 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
340 new_name_and_type_ref_i);
341 break;
342 case JVM_CONSTANT_InterfaceMethodref:
343 entry_name = "IFMethodref";
344 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
345 new_klass_ref_i, new_name_and_type_ref_i);
346 break;
347 case JVM_CONSTANT_Methodref:
348 entry_name = "Methodref";
349 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
350 new_name_and_type_ref_i);
351 break;
352 default:
353 guarantee(false, "bad switch");
354 break;
355 }
356
357 if (klass_ref_i != new_klass_ref_i) {
358 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
359 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
360 }
361 if (name_and_type_ref_i != new_name_and_type_ref_i) {
362 RC_TRACE(0x00080000,
363 ("%s entry@%d name_and_type_index changed: %d to %d",
364 entry_name, *merge_cp_length_p, name_and_type_ref_i,
365 new_name_and_type_ref_i));
366 }
367
368 if (scratch_i != *merge_cp_length_p) {
369 // The new entry in *merge_cp_p is at a different index than
370 // the new entry in scratch_cp so we need to map the index values.
371 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
372 }
373 (*merge_cp_length_p)++;
374 } break;
375
376 // this is an indirect CP entry so it needs special handling
377 case JVM_CONSTANT_MethodType:
378 {
379 int ref_i = scratch_cp->method_type_index_at(scratch_i);
380 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
381 merge_cp_length_p, THREAD);
382 if (new_ref_i != ref_i) {
383 RC_TRACE(0x00080000,
384 ("MethodType entry@%d ref_index change: %d to %d",
385 *merge_cp_length_p, ref_i, new_ref_i));
386 }
387 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
388 if (scratch_i != *merge_cp_length_p) {
389 // The new entry in *merge_cp_p is at a different index than
390 // the new entry in scratch_cp so we need to map the index values.
391 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
392 }
393 (*merge_cp_length_p)++;
394 } break;
395
396 // this is an indirect CP entry so it needs special handling
397 case JVM_CONSTANT_MethodHandle:
398 {
399 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
400 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
401 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
402 merge_cp_length_p, THREAD);
403 if (new_ref_i != ref_i) {
404 RC_TRACE(0x00080000,
405 ("MethodHandle entry@%d ref_index change: %d to %d",
406 *merge_cp_length_p, ref_i, new_ref_i));
407 }
408 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
409 if (scratch_i != *merge_cp_length_p) {
410 // The new entry in *merge_cp_p is at a different index than
411 // the new entry in scratch_cp so we need to map the index values.
412 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
413 }
414 (*merge_cp_length_p)++;
415 } break;
416
417 // this is an indirect CP entry so it needs special handling
418 case JVM_CONSTANT_InvokeDynamic:
419 {
420 // Index of the bootstrap specifier in the operands array
421 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
422 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
423 merge_cp_length_p, THREAD);
424 // The bootstrap method NameAndType_info index
425 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
426 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
427 merge_cp_length_p, THREAD);
428 if (new_bs_i != old_bs_i) {
429 RC_TRACE(0x00080000,
430 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
431 *merge_cp_length_p, old_bs_i, new_bs_i));
432 }
433 if (new_ref_i != old_ref_i) {
434 RC_TRACE(0x00080000,
435 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
436 *merge_cp_length_p, old_ref_i, new_ref_i));
437 }
438
439 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
440 if (scratch_i != *merge_cp_length_p) {
441 // The new entry in *merge_cp_p is at a different index than
442 // the new entry in scratch_cp so we need to map the index values.
443 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
444 }
445 (*merge_cp_length_p)++;
446 } break;
447
448 // At this stage, Class or UnresolvedClass could be here, but not
449 // ClassIndex
450 case JVM_CONSTANT_ClassIndex: // fall through
451
452 // Invalid is used as the tag for the second constant pool entry
453 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
454 // not be seen by itself.
455 case JVM_CONSTANT_Invalid: // fall through
456
457 // At this stage, String could be here, but not StringIndex
458 case JVM_CONSTANT_StringIndex: // fall through
459
460 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
461 // here
462 case JVM_CONSTANT_UnresolvedClassInError: // fall through
463
464 default:
465 {
466 // leave a breadcrumb
467 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
468 ShouldNotReachHere();
469 } break;
470 } // end switch tag value
471 } // end append_entry()
472
473
474 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
475 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
476
477 int new_ref_i = ref_i;
478 bool match = (ref_i < *merge_cp_length_p) &&
479 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
480
481 if (!match) {
482 // forward reference in *merge_cp_p or not a direct match
483 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
484 if (found_i != 0) {
485 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
486 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
487 new_ref_i = found_i;
488 map_index(scratch_cp, ref_i, found_i);
489 } else {
490 // no match found so we have to append this entry to *merge_cp_p
491 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
492 // The above call to append_entry() can only append one entry
493 // so the post call query of *merge_cp_length_p is only for
494 // the sake of consistency.
495 new_ref_i = *merge_cp_length_p - 1;
496 }
497 }
498
499 return new_ref_i;
500 } // end find_or_append_indirect_entry()
501
502
503 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
504 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
505 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
506 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
507 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
508
509 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
510 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
511 merge_cp_length_p, THREAD);
512 if (new_ref_i != old_ref_i) {
513 RC_TRACE(0x00080000,
514 ("operands entry@%d bootstrap method ref_index change: %d to %d",
515 _operands_cur_length, old_ref_i, new_ref_i));
516 }
517
518 Array<u2>* merge_ops = (*merge_cp_p)->operands();
519 int new_bs_i = _operands_cur_length;
520 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
521 // However, the operand_offset_at(0) was set in the extend_operands() call.
522 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
523 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
524 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
525
526 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
527 merge_ops->at_put(new_base++, new_ref_i);
528 merge_ops->at_put(new_base++, argc);
529
530 for (int i = 0; i < argc; i++) {
531 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
532 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
533 merge_cp_length_p, THREAD);
534 merge_ops->at_put(new_base++, new_arg_ref_i);
535 if (new_arg_ref_i != old_arg_ref_i) {
536 RC_TRACE(0x00080000,
537 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
538 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
539 }
540 }
541 if (old_bs_i != _operands_cur_length) {
542 // The bootstrap specifier in *merge_cp_p is at a different index than
543 // that in scratch_cp so we need to map the index values.
544 map_operand_index(old_bs_i, new_bs_i);
545 }
546 _operands_cur_length++;
547 } // end append_operand()
548
549
550 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
551 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
552
553 int new_bs_i = old_bs_i; // bootstrap specifier index
554 bool match = (old_bs_i < _operands_cur_length) &&
555 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
556
557 if (!match) {
558 // forward reference in *merge_cp_p or not a direct match
559 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
560 _operands_cur_length, THREAD);
561 if (found_i != -1) {
562 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
563 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
564 new_bs_i = found_i;
565 map_operand_index(old_bs_i, found_i);
566 } else {
567 // no match found so we have to append this bootstrap specifier to *merge_cp_p
568 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
569 new_bs_i = _operands_cur_length - 1;
570 }
571 }
572 return new_bs_i;
573 } // end find_or_append_operand()
574
575
576 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
577 if (merge_cp->operands() == NULL) {
578 return;
579 }
580 // Shrink the merge_cp operands
581 merge_cp->shrink_operands(_operands_cur_length, CHECK);
582
583 if (RC_TRACE_ENABLED(0x00040000)) {
584 // don't want to loop unless we are tracing
585 int count = 0;
586 for (int i = 1; i < _operands_index_map_p->length(); i++) {
587 int value = _operands_index_map_p->at(i);
588 if (value != -1) {
589 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
590 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
591 count++;
592 }
593 }
594 }
595 // Clean-up
596 _operands_index_map_p = NULL;
597 _operands_cur_length = 0;
598 _operands_index_map_count = 0;
599 } // end finalize_operands_merge()
600
601
602 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
603 instanceKlassHandle the_class,
604 instanceKlassHandle scratch_class) {
605 int i;
606
607 // Check superclasses, or rather their names, since superclasses themselves can be
608 // requested to replace.
609 // Check for NULL superclass first since this might be java.lang.Object
610 if (the_class->super() != scratch_class->super() &&
611 (the_class->super() == NULL || scratch_class->super() == NULL ||
612 the_class->super()->name() !=
613 scratch_class->super()->name())) {
614 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
615 }
616
617 // Check if the number, names and order of directly implemented interfaces are the same.
618 // I think in principle we should just check if the sets of names of directly implemented
619 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
620 // .java file, also changes in .class file) should not matter. However, comparing sets is
621 // technically a bit more difficult, and, more importantly, I am not sure at present that the
622 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
623 // rely on it somewhere.
624 Array<Klass*>* k_interfaces = the_class->local_interfaces();
625 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
626 int n_intfs = k_interfaces->length();
627 if (n_intfs != k_new_interfaces->length()) {
628 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
629 }
630 for (i = 0; i < n_intfs; i++) {
631 if (k_interfaces->at(i)->name() !=
632 k_new_interfaces->at(i)->name()) {
633 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
634 }
635 }
636
637 // Check whether class is in the error init state.
638 if (the_class->is_in_error_state()) {
639 // TBD #5057930: special error code is needed in 1.6
640 return JVMTI_ERROR_INVALID_CLASS;
641 }
642
643 // Check whether class modifiers are the same.
644 jushort old_flags = (jushort) the_class->access_flags().get_flags();
645 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
646 if (old_flags != new_flags) {
647 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
648 }
649
650 // Check if the number, names, types and order of fields declared in these classes
651 // are the same.
652 JavaFieldStream old_fs(the_class);
653 JavaFieldStream new_fs(scratch_class);
654 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
655 // access
656 old_flags = old_fs.access_flags().as_short();
657 new_flags = new_fs.access_flags().as_short();
658 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
659 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
660 }
661 // offset
662 if (old_fs.offset() != new_fs.offset()) {
663 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
664 }
665 // name and signature
666 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
667 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
668 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
669 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
670 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
671 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
672 }
673 }
674
675 // If both streams aren't done then we have a differing number of
676 // fields.
677 if (!old_fs.done() || !new_fs.done()) {
678 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
679 }
680
681 // Do a parallel walk through the old and new methods. Detect
682 // cases where they match (exist in both), have been added in
683 // the new methods, or have been deleted (exist only in the
684 // old methods). The class file parser places methods in order
685 // by method name, but does not order overloaded methods by
686 // signature. In order to determine what fate befell the methods,
687 // this code places the overloaded new methods that have matching
688 // old methods in the same order as the old methods and places
689 // new overloaded methods at the end of overloaded methods of
690 // that name. The code for this order normalization is adapted
691 // from the algorithm used in InstanceKlass::find_method().
692 // Since we are swapping out of order entries as we find them,
693 // we only have to search forward through the overloaded methods.
694 // Methods which are added and have the same name as an existing
695 // method (but different signature) will be put at the end of
696 // the methods with that name, and the name mismatch code will
697 // handle them.
698 Array<Method*>* k_old_methods(the_class->methods());
699 Array<Method*>* k_new_methods(scratch_class->methods());
700 int n_old_methods = k_old_methods->length();
701 int n_new_methods = k_new_methods->length();
702 Thread* thread = Thread::current();
703
704 int ni = 0;
705 int oi = 0;
706 while (true) {
707 Method* k_old_method;
708 Method* k_new_method;
709 enum { matched, added, deleted, undetermined } method_was = undetermined;
710
711 if (oi >= n_old_methods) {
712 if (ni >= n_new_methods) {
713 break; // we've looked at everything, done
714 }
715 // New method at the end
716 k_new_method = k_new_methods->at(ni);
717 method_was = added;
718 } else if (ni >= n_new_methods) {
719 // Old method, at the end, is deleted
720 k_old_method = k_old_methods->at(oi);
721 method_was = deleted;
722 } else {
723 // There are more methods in both the old and new lists
724 k_old_method = k_old_methods->at(oi);
725 k_new_method = k_new_methods->at(ni);
726 if (k_old_method->name() != k_new_method->name()) {
727 // Methods are sorted by method name, so a mismatch means added
728 // or deleted
729 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
730 method_was = added;
731 } else {
732 method_was = deleted;
733 }
734 } else if (k_old_method->signature() == k_new_method->signature()) {
735 // Both the name and signature match
736 method_was = matched;
737 } else {
738 // The name matches, but the signature doesn't, which means we have to
739 // search forward through the new overloaded methods.
740 int nj; // outside the loop for post-loop check
741 for (nj = ni + 1; nj < n_new_methods; nj++) {
742 Method* m = k_new_methods->at(nj);
743 if (k_old_method->name() != m->name()) {
744 // reached another method name so no more overloaded methods
745 method_was = deleted;
746 break;
747 }
748 if (k_old_method->signature() == m->signature()) {
749 // found a match so swap the methods
750 k_new_methods->at_put(ni, m);
751 k_new_methods->at_put(nj, k_new_method);
752 k_new_method = m;
753 method_was = matched;
754 break;
755 }
756 }
757
758 if (nj >= n_new_methods) {
759 // reached the end without a match; so method was deleted
760 method_was = deleted;
761 }
762 }
763 }
764
765 switch (method_was) {
766 case matched:
767 // methods match, be sure modifiers do too
768 old_flags = (jushort) k_old_method->access_flags().get_flags();
769 new_flags = (jushort) k_new_method->access_flags().get_flags();
770 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
771 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
772 }
773 {
774 u2 new_num = k_new_method->method_idnum();
775 u2 old_num = k_old_method->method_idnum();
776 if (new_num != old_num) {
777 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
778 if (idnum_owner != NULL) {
779 // There is already a method assigned this idnum -- switch them
780 idnum_owner->set_method_idnum(new_num);
781 }
782 k_new_method->set_method_idnum(old_num);
783 if (thread->has_pending_exception()) {
784 return JVMTI_ERROR_OUT_OF_MEMORY;
785 }
786 }
787 }
788 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
789 k_new_method->name_and_sig_as_C_string(), ni,
790 k_old_method->name_and_sig_as_C_string(), oi));
791 // advance to next pair of methods
792 ++oi;
793 ++ni;
794 break;
795 case added:
796 // method added, see if it is OK
797 new_flags = (jushort) k_new_method->access_flags().get_flags();
798 if ((new_flags & JVM_ACC_PRIVATE) == 0
799 // hack: private should be treated as final, but alas
800 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
801 ) {
802 // new methods must be private
803 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
804 }
805 {
806 u2 num = the_class->next_method_idnum();
807 if (num == ConstMethod::UNSET_IDNUM) {
808 // cannot add any more methods
809 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
810 }
811 u2 new_num = k_new_method->method_idnum();
812 Method* idnum_owner = scratch_class->method_with_idnum(num);
813 if (idnum_owner != NULL) {
814 // There is already a method assigned this idnum -- switch them
815 idnum_owner->set_method_idnum(new_num);
816 }
817 k_new_method->set_method_idnum(num);
818 if (thread->has_pending_exception()) {
819 return JVMTI_ERROR_OUT_OF_MEMORY;
820 }
821 }
822 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
823 k_new_method->name_and_sig_as_C_string(), ni));
824 ++ni; // advance to next new method
825 break;
826 case deleted:
827 // method deleted, see if it is OK
828 old_flags = (jushort) k_old_method->access_flags().get_flags();
829 if ((old_flags & JVM_ACC_PRIVATE) == 0
830 // hack: private should be treated as final, but alas
831 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
832 ) {
833 // deleted methods must be private
834 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
835 }
836 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
837 k_old_method->name_and_sig_as_C_string(), oi));
838 ++oi; // advance to next old method
839 break;
840 default:
841 ShouldNotReachHere();
842 }
843 }
844
845 return JVMTI_ERROR_NONE;
846 }
847
848
849 // Find new constant pool index value for old constant pool index value
850 // by seaching the index map. Returns zero (0) if there is no mapped
851 // value for the old constant pool index.
852 int VM_RedefineClasses::find_new_index(int old_index) {
853 if (_index_map_count == 0) {
854 // map is empty so nothing can be found
855 return 0;
856 }
857
858 if (old_index < 1 || old_index >= _index_map_p->length()) {
859 // The old_index is out of range so it is not mapped. This should
860 // not happen in regular constant pool merging use, but it can
861 // happen if a corrupt annotation is processed.
862 return 0;
863 }
864
865 int value = _index_map_p->at(old_index);
866 if (value == -1) {
867 // the old_index is not mapped
868 return 0;
869 }
870
871 return value;
872 } // end find_new_index()
873
874
875 // Find new bootstrap specifier index value for old bootstrap specifier index
876 // value by seaching the index map. Returns unused index (-1) if there is
877 // no mapped value for the old bootstrap specifier index.
878 int VM_RedefineClasses::find_new_operand_index(int old_index) {
879 if (_operands_index_map_count == 0) {
880 // map is empty so nothing can be found
881 return -1;
882 }
883
884 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
885 // The old_index is out of range so it is not mapped.
886 // This should not happen in regular constant pool merging use.
887 return -1;
888 }
889
890 int value = _operands_index_map_p->at(old_index);
891 if (value == -1) {
892 // the old_index is not mapped
893 return -1;
894 }
895
896 return value;
897 } // end find_new_operand_index()
898
899
900 // Returns true if the current mismatch is due to a resolved/unresolved
901 // class pair. Otherwise, returns false.
902 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
903 int index1, constantPoolHandle cp2, int index2) {
904
905 jbyte t1 = cp1->tag_at(index1).value();
906 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
907 return false; // wrong entry type; not our special case
908 }
909
910 jbyte t2 = cp2->tag_at(index2).value();
911 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
912 return false; // wrong entry type; not our special case
913 }
914
915 if (t1 == t2) {
916 return false; // not a mismatch; not our special case
917 }
918
919 char *s1 = cp1->klass_name_at(index1)->as_C_string();
920 char *s2 = cp2->klass_name_at(index2)->as_C_string();
921 if (strcmp(s1, s2) != 0) {
922 return false; // strings don't match; not our special case
923 }
924
925 return true; // made it through the gauntlet; this is our special case
926 } // end is_unresolved_class_mismatch()
927
928
929 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
930
931 // For consistency allocate memory using os::malloc wrapper.
932 _scratch_classes = (Klass**)
933 os::malloc(sizeof(Klass*) * _class_count, mtClass);
934 if (_scratch_classes == NULL) {
935 return JVMTI_ERROR_OUT_OF_MEMORY;
936 }
937 // Zero initialize the _scratch_classes array.
938 for (int i = 0; i < _class_count; i++) {
939 _scratch_classes[i] = NULL;
940 }
941
942 ResourceMark rm(THREAD);
943
944 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
945 // state can only be NULL if the current thread is exiting which
946 // should not happen since we're trying to do a RedefineClasses
947 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
948 for (int i = 0; i < _class_count; i++) {
949 // Create HandleMark so that any handles created while loading new class
950 // versions are deleted. Constant pools are deallocated while merging
951 // constant pools
952 HandleMark hm(THREAD);
953
954 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
955 // classes for primitives cannot be redefined
956 if (!is_modifiable_class(mirror)) {
957 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
958 }
959 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
960 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
961 Symbol* the_class_sym = the_class->name();
962
963 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
964 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
965 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
966 the_class->external_name(), _class_load_kind,
967 os::available_memory() >> 10));
968
969 ClassFileStream st((u1*) _class_defs[i].class_bytes,
970 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
971
972 // Parse the stream.
973 Handle the_class_loader(THREAD, the_class->class_loader());
974 Handle protection_domain(THREAD, the_class->protection_domain());
975 // Set redefined class handle in JvmtiThreadState class.
976 // This redefined class is sent to agent event handler for class file
977 // load hook event.
978 state->set_class_being_redefined(&the_class, _class_load_kind);
979
980 Klass* k = SystemDictionary::parse_stream(the_class_sym,
981 the_class_loader,
982 protection_domain,
983 &st,
984 THREAD);
985 // Clear class_being_redefined just to be sure.
986 state->clear_class_being_redefined();
987
988 // TODO: if this is retransform, and nothing changed we can skip it
989
990 instanceKlassHandle scratch_class (THREAD, k);
991
992 // Need to clean up allocated InstanceKlass if there's an error so assign
993 // the result here. Caller deallocates all the scratch classes in case of
994 // an error.
995 _scratch_classes[i] = k;
996
997 if (HAS_PENDING_EXCEPTION) {
998 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
999 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1000 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1001 ex_name->as_C_string()));
1002 CLEAR_PENDING_EXCEPTION;
1003
1004 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1005 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1006 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1007 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1008 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1009 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1010 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1011 // The message will be "XXX (wrong name: YYY)"
1012 return JVMTI_ERROR_NAMES_DONT_MATCH;
1013 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1014 return JVMTI_ERROR_OUT_OF_MEMORY;
1015 } else { // Just in case more exceptions can be thrown..
1016 return JVMTI_ERROR_FAILS_VERIFICATION;
1017 }
1018 }
1019
1020 // Ensure class is linked before redefine
1021 if (!the_class->is_linked()) {
1022 the_class->link_class(THREAD);
1023 if (HAS_PENDING_EXCEPTION) {
1024 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1025 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1026 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1027 ex_name->as_C_string()));
1028 CLEAR_PENDING_EXCEPTION;
1029 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1030 return JVMTI_ERROR_OUT_OF_MEMORY;
1031 } else {
1032 return JVMTI_ERROR_INTERNAL;
1033 }
1034 }
1035 }
1036
1037 // Do the validity checks in compare_and_normalize_class_versions()
1038 // before verifying the byte codes. By doing these checks first, we
1039 // limit the number of functions that require redirection from
1040 // the_class to scratch_class. In particular, we don't have to
1041 // modify JNI GetSuperclass() and thus won't change its performance.
1042 jvmtiError res = compare_and_normalize_class_versions(the_class,
1043 scratch_class);
1044 if (res != JVMTI_ERROR_NONE) {
1045 return res;
1046 }
1047
1048 // verify what the caller passed us
1049 {
1050 // The bug 6214132 caused the verification to fail.
1051 // Information about the_class and scratch_class is temporarily
1052 // recorded into jvmtiThreadState. This data is used to redirect
1053 // the_class to scratch_class in the JVM_* functions called by the
1054 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1055 // description.
1056 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1057 Verifier::verify(
1058 scratch_class, Verifier::ThrowException, true, THREAD);
1059 }
1060
1061 if (HAS_PENDING_EXCEPTION) {
1062 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1063 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1064 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1065 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1066 CLEAR_PENDING_EXCEPTION;
1067 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1068 return JVMTI_ERROR_OUT_OF_MEMORY;
1069 } else {
1070 // tell the caller the bytecodes are bad
1071 return JVMTI_ERROR_FAILS_VERIFICATION;
1072 }
1073 }
1074
1075 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1076 if (HAS_PENDING_EXCEPTION) {
1077 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1078 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1079 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1080 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1081 CLEAR_PENDING_EXCEPTION;
1082 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1083 return JVMTI_ERROR_OUT_OF_MEMORY;
1084 } else {
1085 return JVMTI_ERROR_INTERNAL;
1086 }
1087 }
1088
1089 if (VerifyMergedCPBytecodes) {
1090 // verify what we have done during constant pool merging
1091 {
1092 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1093 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1094 }
1095
1096 if (HAS_PENDING_EXCEPTION) {
1097 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1098 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1099 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1100 ("verify_byte_codes post merge-CP exception: '%s'",
1101 ex_name->as_C_string()));
1102 CLEAR_PENDING_EXCEPTION;
1103 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1104 return JVMTI_ERROR_OUT_OF_MEMORY;
1105 } else {
1106 // tell the caller that constant pool merging screwed up
1107 return JVMTI_ERROR_INTERNAL;
1108 }
1109 }
1110 }
1111
1112 Rewriter::rewrite(scratch_class, THREAD);
1113 if (!HAS_PENDING_EXCEPTION) {
1114 scratch_class->link_methods(THREAD);
1115 }
1116 if (HAS_PENDING_EXCEPTION) {
1117 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1118 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1119 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1120 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1121 CLEAR_PENDING_EXCEPTION;
1122 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1123 return JVMTI_ERROR_OUT_OF_MEMORY;
1124 } else {
1125 return JVMTI_ERROR_INTERNAL;
1126 }
1127 }
1128
1129 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1130 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1131 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1132 the_class->external_name(), os::available_memory() >> 10));
1133 }
1134
1135 return JVMTI_ERROR_NONE;
1136 }
1137
1138
1139 // Map old_index to new_index as needed. scratch_cp is only needed
1140 // for RC_TRACE() calls.
1141 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1142 int old_index, int new_index) {
1143 if (find_new_index(old_index) != 0) {
1144 // old_index is already mapped
1145 return;
1146 }
1147
1148 if (old_index == new_index) {
1149 // no mapping is needed
1150 return;
1151 }
1152
1153 _index_map_p->at_put(old_index, new_index);
1154 _index_map_count++;
1155
1156 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1157 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1158 } // end map_index()
1159
1160
1161 // Map old_index to new_index as needed.
1162 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1163 if (find_new_operand_index(old_index) != -1) {
1164 // old_index is already mapped
1165 return;
1166 }
1167
1168 if (old_index == new_index) {
1169 // no mapping is needed
1170 return;
1171 }
1172
1173 _operands_index_map_p->at_put(old_index, new_index);
1174 _operands_index_map_count++;
1175
1176 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1177 } // end map_index()
1178
1179
1180 // Merge old_cp and scratch_cp and return the results of the merge via
1181 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1182 // merge_cp_length_p. The entries in old_cp occupy the same locations
1183 // in *merge_cp_p. Also creates a map of indices from entries in
1184 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1185 // entries are only created for entries in scratch_cp that occupy a
1186 // different location in *merged_cp_p.
1187 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1188 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1189 int *merge_cp_length_p, TRAPS) {
1190
1191 if (merge_cp_p == NULL) {
1192 assert(false, "caller must provide scratch constantPool");
1193 return false; // robustness
1194 }
1195 if (merge_cp_length_p == NULL) {
1196 assert(false, "caller must provide scratch CP length");
1197 return false; // robustness
1198 }
1199 // Worst case we need old_cp->length() + scratch_cp()->length(),
1200 // but the caller might be smart so make sure we have at least
1201 // the minimum.
1202 if ((*merge_cp_p)->length() < old_cp->length()) {
1203 assert(false, "merge area too small");
1204 return false; // robustness
1205 }
1206
1207 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1208 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1209 scratch_cp->length()));
1210
1211 {
1212 // Pass 0:
1213 // The old_cp is copied to *merge_cp_p; this means that any code
1214 // using old_cp does not have to change. This work looks like a
1215 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1216 // handle one special case:
1217 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1218 // This will make verification happy.
1219
1220 int old_i; // index into old_cp
1221
1222 // index zero (0) is not used in constantPools
1223 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1224 // leave debugging crumb
1225 jbyte old_tag = old_cp->tag_at(old_i).value();
1226 switch (old_tag) {
1227 case JVM_CONSTANT_Class:
1228 case JVM_CONSTANT_UnresolvedClass:
1229 // revert the copy to JVM_CONSTANT_UnresolvedClass
1230 // May be resolving while calling this so do the same for
1231 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1232 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1233 old_cp->klass_name_at(old_i));
1234 break;
1235
1236 case JVM_CONSTANT_Double:
1237 case JVM_CONSTANT_Long:
1238 // just copy the entry to *merge_cp_p, but double and long take
1239 // two constant pool entries
1240 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1241 old_i++;
1242 break;
1243
1244 default:
1245 // just copy the entry to *merge_cp_p
1246 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1247 break;
1248 }
1249 } // end for each old_cp entry
1250
1251 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1252 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1253
1254 // We don't need to sanity check that *merge_cp_length_p is within
1255 // *merge_cp_p bounds since we have the minimum on-entry check above.
1256 (*merge_cp_length_p) = old_i;
1257 }
1258
1259 // merge_cp_len should be the same as old_cp->length() at this point
1260 // so this trace message is really a "warm-and-breathing" message.
1261 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1262 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1263
1264 int scratch_i; // index into scratch_cp
1265 {
1266 // Pass 1a:
1267 // Compare scratch_cp entries to the old_cp entries that we have
1268 // already copied to *merge_cp_p. In this pass, we are eliminating
1269 // exact duplicates (matching entry at same index) so we only
1270 // compare entries in the common indice range.
1271 int increment = 1;
1272 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1273 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1274 switch (scratch_cp->tag_at(scratch_i).value()) {
1275 case JVM_CONSTANT_Double:
1276 case JVM_CONSTANT_Long:
1277 // double and long take two constant pool entries
1278 increment = 2;
1279 break;
1280
1281 default:
1282 increment = 1;
1283 break;
1284 }
1285
1286 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1287 scratch_i, CHECK_0);
1288 if (match) {
1289 // found a match at the same index so nothing more to do
1290 continue;
1291 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1292 *merge_cp_p, scratch_i)) {
1293 // The mismatch in compare_entry_to() above is because of a
1294 // resolved versus unresolved class entry at the same index
1295 // with the same string value. Since Pass 0 reverted any
1296 // class entries to unresolved class entries in *merge_cp_p,
1297 // we go with the unresolved class entry.
1298 continue;
1299 }
1300
1301 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1302 CHECK_0);
1303 if (found_i != 0) {
1304 guarantee(found_i != scratch_i,
1305 "compare_entry_to() and find_matching_entry() do not agree");
1306
1307 // Found a matching entry somewhere else in *merge_cp_p so
1308 // just need a mapping entry.
1309 map_index(scratch_cp, scratch_i, found_i);
1310 continue;
1311 }
1312
1313 // The find_matching_entry() call above could fail to find a match
1314 // due to a resolved versus unresolved class or string entry situation
1315 // like we solved above with the is_unresolved_*_mismatch() calls.
1316 // However, we would have to call is_unresolved_*_mismatch() over
1317 // all of *merge_cp_p (potentially) and that doesn't seem to be
1318 // worth the time.
1319
1320 // No match found so we have to append this entry and any unique
1321 // referenced entries to *merge_cp_p.
1322 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1323 CHECK_0);
1324 }
1325 }
1326
1327 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1328 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1329 *merge_cp_length_p, scratch_i, _index_map_count));
1330
1331 if (scratch_i < scratch_cp->length()) {
1332 // Pass 1b:
1333 // old_cp is smaller than scratch_cp so there are entries in
1334 // scratch_cp that we have not yet processed. We take care of
1335 // those now.
1336 int increment = 1;
1337 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1338 switch (scratch_cp->tag_at(scratch_i).value()) {
1339 case JVM_CONSTANT_Double:
1340 case JVM_CONSTANT_Long:
1341 // double and long take two constant pool entries
1342 increment = 2;
1343 break;
1344
1345 default:
1346 increment = 1;
1347 break;
1348 }
1349
1350 int found_i =
1351 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1352 if (found_i != 0) {
1353 // Found a matching entry somewhere else in *merge_cp_p so
1354 // just need a mapping entry.
1355 map_index(scratch_cp, scratch_i, found_i);
1356 continue;
1357 }
1358
1359 // No match found so we have to append this entry and any unique
1360 // referenced entries to *merge_cp_p.
1361 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1362 CHECK_0);
1363 }
1364
1365 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1366 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1367 *merge_cp_length_p, scratch_i, _index_map_count));
1368 }
1369 finalize_operands_merge(*merge_cp_p, THREAD);
1370
1371 return true;
1372 } // end merge_constant_pools()
1373
1374
1375 // Scoped object to clean up the constant pool(s) created for merging
1376 class MergeCPCleaner {
1377 ClassLoaderData* _loader_data;
1378 ConstantPool* _cp;
1379 ConstantPool* _scratch_cp;
1380 public:
1381 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1382 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1383 ~MergeCPCleaner() {
1384 _loader_data->add_to_deallocate_list(_cp);
1385 if (_scratch_cp != NULL) {
1386 _loader_data->add_to_deallocate_list(_scratch_cp);
1387 }
1388 }
1389 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1390 };
1391
1392 // Merge constant pools between the_class and scratch_class and
1393 // potentially rewrite bytecodes in scratch_class to use the merged
1394 // constant pool.
1395 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1396 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1397 TRAPS) {
1398 // worst case merged constant pool length is old and new combined
1399 int merge_cp_length = the_class->constants()->length()
1400 + scratch_class->constants()->length();
1401
1402 // Constant pools are not easily reused so we allocate a new one
1403 // each time.
1404 // merge_cp is created unsafe for concurrent GC processing. It
1405 // should be marked safe before discarding it. Even though
1406 // garbage, if it crosses a card boundary, it may be scanned
1407 // in order to find the start of the first complete object on the card.
1408 ClassLoaderData* loader_data = the_class->class_loader_data();
1409 ConstantPool* merge_cp_oop =
1410 ConstantPool::allocate(loader_data,
1411 merge_cp_length,
1412 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1413 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1414
1415 HandleMark hm(THREAD); // make sure handles are cleared before
1416 // MergeCPCleaner clears out merge_cp_oop
1417 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1418
1419 // Get constants() from the old class because it could have been rewritten
1420 // while we were at a safepoint allocating a new constant pool.
1421 constantPoolHandle old_cp(THREAD, the_class->constants());
1422 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1423
1424 // If the length changed, the class was redefined out from under us. Return
1425 // an error.
1426 if (merge_cp_length != the_class->constants()->length()
1427 + scratch_class->constants()->length()) {
1428 return JVMTI_ERROR_INTERNAL;
1429 }
1430
1431 // Update the version number of the constant pool
1432 merge_cp->increment_and_save_version(old_cp->version());
1433
1434 ResourceMark rm(THREAD);
1435 _index_map_count = 0;
1436 _index_map_p = new intArray(scratch_cp->length(), -1);
1437
1438 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1439 _operands_index_map_count = 0;
1440 _operands_index_map_p = new intArray(
1441 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1442
1443 // reference to the cp holder is needed for copy_operands()
1444 merge_cp->set_pool_holder(scratch_class());
1445 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1446 &merge_cp_length, THREAD);
1447 merge_cp->set_pool_holder(NULL);
1448
1449 if (!result) {
1450 // The merge can fail due to memory allocation failure or due
1451 // to robustness checks.
1452 return JVMTI_ERROR_INTERNAL;
1453 }
1454
1455 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1456 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1457
1458 if (_index_map_count == 0) {
1459 // there is nothing to map between the new and merged constant pools
1460
1461 if (old_cp->length() == scratch_cp->length()) {
1462 // The old and new constant pools are the same length and the
1463 // index map is empty. This means that the three constant pools
1464 // are equivalent (but not the same). Unfortunately, the new
1465 // constant pool has not gone through link resolution nor have
1466 // the new class bytecodes gone through constant pool cache
1467 // rewriting so we can't use the old constant pool with the new
1468 // class.
1469
1470 // toss the merged constant pool at return
1471 } else if (old_cp->length() < scratch_cp->length()) {
1472 // The old constant pool has fewer entries than the new constant
1473 // pool and the index map is empty. This means the new constant
1474 // pool is a superset of the old constant pool. However, the old
1475 // class bytecodes have already gone through constant pool cache
1476 // rewriting so we can't use the new constant pool with the old
1477 // class.
1478
1479 // toss the merged constant pool at return
1480 } else {
1481 // The old constant pool has more entries than the new constant
1482 // pool and the index map is empty. This means that both the old
1483 // and merged constant pools are supersets of the new constant
1484 // pool.
1485
1486 // Replace the new constant pool with a shrunken copy of the
1487 // merged constant pool
1488 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1489 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1490 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1491 // It can't be cleaned up while there are handles to it.
1492 cp_cleaner.add_scratch_cp(scratch_cp());
1493 }
1494 } else {
1495 if (RC_TRACE_ENABLED(0x00040000)) {
1496 // don't want to loop unless we are tracing
1497 int count = 0;
1498 for (int i = 1; i < _index_map_p->length(); i++) {
1499 int value = _index_map_p->at(i);
1500
1501 if (value != -1) {
1502 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1503 ("index_map[%d]: old=%d new=%d", count, i, value));
1504 count++;
1505 }
1506 }
1507 }
1508
1509 // We have entries mapped between the new and merged constant pools
1510 // so we have to rewrite some constant pool references.
1511 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1512 return JVMTI_ERROR_INTERNAL;
1513 }
1514
1515 // Replace the new constant pool with a shrunken copy of the
1516 // merged constant pool so now the rewritten bytecodes have
1517 // valid references; the previous new constant pool will get
1518 // GCed.
1519 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1520 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1521 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1522 // It can't be cleaned up while there are handles to it.
1523 cp_cleaner.add_scratch_cp(scratch_cp());
1524 }
1525
1526 return JVMTI_ERROR_NONE;
1527 } // end merge_cp_and_rewrite()
1528
1529
1530 // Rewrite constant pool references in klass scratch_class.
1531 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1532 TRAPS) {
1533
1534 // rewrite constant pool references in the methods:
1535 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1536 // propagate failure back to caller
1537 return false;
1538 }
1539
1540 // rewrite constant pool references in the class_annotations:
1541 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1542 // propagate failure back to caller
1543 return false;
1544 }
1545
1546 // rewrite constant pool references in the fields_annotations:
1547 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1548 // propagate failure back to caller
1549 return false;
1550 }
1551
1552 // rewrite constant pool references in the methods_annotations:
1553 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1554 // propagate failure back to caller
1555 return false;
1556 }
1557
1558 // rewrite constant pool references in the methods_parameter_annotations:
1559 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1560 THREAD)) {
1561 // propagate failure back to caller
1562 return false;
1563 }
1564
1565 // rewrite constant pool references in the methods_default_annotations:
1566 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1567 THREAD)) {
1568 // propagate failure back to caller
1569 return false;
1570 }
1571
1572 // rewrite constant pool references in the class_type_annotations:
1573 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1574 // propagate failure back to caller
1575 return false;
1576 }
1577
1578 // rewrite constant pool references in the fields_type_annotations:
1579 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1580 // propagate failure back to caller
1581 return false;
1582 }
1583
1584 // rewrite constant pool references in the methods_type_annotations:
1585 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1586 // propagate failure back to caller
1587 return false;
1588 }
1589
1590 // There can be type annotations in the Code part of a method_info attribute.
1591 // These annotations are not accessible, even by reflection.
1592 // Currently they are not even parsed by the ClassFileParser.
1593 // If runtime access is added they will also need to be rewritten.
1594
1595 // rewrite source file name index:
1596 u2 source_file_name_idx = scratch_class->source_file_name_index();
1597 if (source_file_name_idx != 0) {
1598 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1599 if (new_source_file_name_idx != 0) {
1600 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1601 }
1602 }
1603
1604 // rewrite class generic signature index:
1605 u2 generic_signature_index = scratch_class->generic_signature_index();
1606 if (generic_signature_index != 0) {
1607 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1608 if (new_generic_signature_index != 0) {
1609 scratch_class->set_generic_signature_index(new_generic_signature_index);
1610 }
1611 }
1612
1613 return true;
1614 } // end rewrite_cp_refs()
1615
1616 // Rewrite constant pool references in the methods.
1617 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1618 instanceKlassHandle scratch_class, TRAPS) {
1619
1620 Array<Method*>* methods = scratch_class->methods();
1621
1622 if (methods == NULL || methods->length() == 0) {
1623 // no methods so nothing to do
1624 return true;
1625 }
1626
1627 // rewrite constant pool references in the methods:
1628 for (int i = methods->length() - 1; i >= 0; i--) {
1629 methodHandle method(THREAD, methods->at(i));
1630 methodHandle new_method;
1631 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1632 if (!new_method.is_null()) {
1633 // the method has been replaced so save the new method version
1634 // even in the case of an exception. original method is on the
1635 // deallocation list.
1636 methods->at_put(i, new_method());
1637 }
1638 if (HAS_PENDING_EXCEPTION) {
1639 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1640 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1641 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1642 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1643 // Need to clear pending exception here as the super caller sets
1644 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1645 CLEAR_PENDING_EXCEPTION;
1646 return false;
1647 }
1648 }
1649
1650 return true;
1651 }
1652
1653
1654 // Rewrite constant pool references in the specific method. This code
1655 // was adapted from Rewriter::rewrite_method().
1656 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1657 methodHandle *new_method_p, TRAPS) {
1658
1659 *new_method_p = methodHandle(); // default is no new method
1660
1661 // We cache a pointer to the bytecodes here in code_base. If GC
1662 // moves the Method*, then the bytecodes will also move which
1663 // will likely cause a crash. We create a No_Safepoint_Verifier
1664 // object to detect whether we pass a possible safepoint in this
1665 // code block.
1666 No_Safepoint_Verifier nsv;
1667
1668 // Bytecodes and their length
1669 address code_base = method->code_base();
1670 int code_length = method->code_size();
1671
1672 int bc_length;
1673 for (int bci = 0; bci < code_length; bci += bc_length) {
1674 address bcp = code_base + bci;
1675 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1676
1677 bc_length = Bytecodes::length_for(c);
1678 if (bc_length == 0) {
1679 // More complicated bytecodes report a length of zero so
1680 // we have to try again a slightly different way.
1681 bc_length = Bytecodes::length_at(method(), bcp);
1682 }
1683
1684 assert(bc_length != 0, "impossible bytecode length");
1685
1686 switch (c) {
1687 case Bytecodes::_ldc:
1688 {
1689 int cp_index = *(bcp + 1);
1690 int new_index = find_new_index(cp_index);
1691
1692 if (StressLdcRewrite && new_index == 0) {
1693 // If we are stressing ldc -> ldc_w rewriting, then we
1694 // always need a new_index value.
1695 new_index = cp_index;
1696 }
1697 if (new_index != 0) {
1698 // the original index is mapped so we have more work to do
1699 if (!StressLdcRewrite && new_index <= max_jubyte) {
1700 // The new value can still use ldc instead of ldc_w
1701 // unless we are trying to stress ldc -> ldc_w rewriting
1702 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1703 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1704 bcp, cp_index, new_index));
1705 *(bcp + 1) = new_index;
1706 } else {
1707 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1708 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1709 Bytecodes::name(c), bcp, cp_index, new_index));
1710 // the new value needs ldc_w instead of ldc
1711 u_char inst_buffer[4]; // max instruction size is 4 bytes
1712 bcp = (address)inst_buffer;
1713 // construct new instruction sequence
1714 *bcp = Bytecodes::_ldc_w;
1715 bcp++;
1716 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1717 // See comment below for difference between put_Java_u2()
1718 // and put_native_u2().
1719 Bytes::put_Java_u2(bcp, new_index);
1720
1721 Relocator rc(method, NULL /* no RelocatorListener needed */);
1722 methodHandle m;
1723 {
1724 Pause_No_Safepoint_Verifier pnsv(&nsv);
1725
1726 // ldc is 2 bytes and ldc_w is 3 bytes
1727 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1728 }
1729
1730 // return the new method so that the caller can update
1731 // the containing class
1732 *new_method_p = method = m;
1733 // switch our bytecode processing loop from the old method
1734 // to the new method
1735 code_base = method->code_base();
1736 code_length = method->code_size();
1737 bcp = code_base + bci;
1738 c = (Bytecodes::Code)(*bcp);
1739 bc_length = Bytecodes::length_for(c);
1740 assert(bc_length != 0, "sanity check");
1741 } // end we need ldc_w instead of ldc
1742 } // end if there is a mapped index
1743 } break;
1744
1745 // these bytecodes have a two-byte constant pool index
1746 case Bytecodes::_anewarray : // fall through
1747 case Bytecodes::_checkcast : // fall through
1748 case Bytecodes::_getfield : // fall through
1749 case Bytecodes::_getstatic : // fall through
1750 case Bytecodes::_instanceof : // fall through
1751 case Bytecodes::_invokedynamic : // fall through
1752 case Bytecodes::_invokeinterface: // fall through
1753 case Bytecodes::_invokespecial : // fall through
1754 case Bytecodes::_invokestatic : // fall through
1755 case Bytecodes::_invokevirtual : // fall through
1756 case Bytecodes::_ldc_w : // fall through
1757 case Bytecodes::_ldc2_w : // fall through
1758 case Bytecodes::_multianewarray : // fall through
1759 case Bytecodes::_new : // fall through
1760 case Bytecodes::_putfield : // fall through
1761 case Bytecodes::_putstatic :
1762 {
1763 address p = bcp + 1;
1764 int cp_index = Bytes::get_Java_u2(p);
1765 int new_index = find_new_index(cp_index);
1766 if (new_index != 0) {
1767 // the original index is mapped so update w/ new value
1768 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1769 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1770 bcp, cp_index, new_index));
1771 // Rewriter::rewrite_method() uses put_native_u2() in this
1772 // situation because it is reusing the constant pool index
1773 // location for a native index into the ConstantPoolCache.
1774 // Since we are updating the constant pool index prior to
1775 // verification and ConstantPoolCache initialization, we
1776 // need to keep the new index in Java byte order.
1777 Bytes::put_Java_u2(p, new_index);
1778 }
1779 } break;
1780 }
1781 } // end for each bytecode
1782
1783 // We also need to rewrite the parameter name indexes, if there is
1784 // method parameter data present
1785 if(method->has_method_parameters()) {
1786 const int len = method->method_parameters_length();
1787 MethodParametersElement* elem = method->method_parameters_start();
1788
1789 for (int i = 0; i < len; i++) {
1790 const u2 cp_index = elem[i].name_cp_index;
1791 const u2 new_cp_index = find_new_index(cp_index);
1792 if (new_cp_index != 0) {
1793 elem[i].name_cp_index = new_cp_index;
1794 }
1795 }
1796 }
1797 } // end rewrite_cp_refs_in_method()
1798
1799
1800 // Rewrite constant pool references in the class_annotations field.
1801 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1802 instanceKlassHandle scratch_class, TRAPS) {
1803
1804 AnnotationArray* class_annotations = scratch_class->class_annotations();
1805 if (class_annotations == NULL || class_annotations->length() == 0) {
1806 // no class_annotations so nothing to do
1807 return true;
1808 }
1809
1810 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1811 ("class_annotations length=%d", class_annotations->length()));
1812
1813 int byte_i = 0; // byte index into class_annotations
1814 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1815 THREAD);
1816 }
1817
1818
1819 // Rewrite constant pool references in an annotations typeArray. This
1820 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1821 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1822 //
1823 // annotations_typeArray {
1824 // u2 num_annotations;
1825 // annotation annotations[num_annotations];
1826 // }
1827 //
1828 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1829 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1830
1831 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1832 // not enough room for num_annotations field
1833 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1834 ("length() is too small for num_annotations field"));
1835 return false;
1836 }
1837
1838 u2 num_annotations = Bytes::get_Java_u2((address)
1839 annotations_typeArray->adr_at(byte_i_ref));
1840 byte_i_ref += 2;
1841
1842 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1843 ("num_annotations=%d", num_annotations));
1844
1845 int calc_num_annotations = 0;
1846 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1847 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1848 byte_i_ref, THREAD)) {
1849 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1850 ("bad annotation_struct at %d", calc_num_annotations));
1851 // propagate failure back to caller
1852 return false;
1853 }
1854 }
1855 assert(num_annotations == calc_num_annotations, "sanity check");
1856
1857 return true;
1858 } // end rewrite_cp_refs_in_annotations_typeArray()
1859
1860
1861 // Rewrite constant pool references in the annotation struct portion of
1862 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1863 // the 2nd-edition of the VM spec:
1864 //
1865 // struct annotation {
1866 // u2 type_index;
1867 // u2 num_element_value_pairs;
1868 // {
1869 // u2 element_name_index;
1870 // element_value value;
1871 // } element_value_pairs[num_element_value_pairs];
1872 // }
1873 //
1874 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1875 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1876 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1877 // not enough room for smallest annotation_struct
1878 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1879 ("length() is too small for annotation_struct"));
1880 return false;
1881 }
1882
1883 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1884 byte_i_ref, "mapped old type_index=%d", THREAD);
1885
1886 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1887 annotations_typeArray->adr_at(byte_i_ref));
1888 byte_i_ref += 2;
1889
1890 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1891 ("type_index=%d num_element_value_pairs=%d", type_index,
1892 num_element_value_pairs));
1893
1894 int calc_num_element_value_pairs = 0;
1895 for (; calc_num_element_value_pairs < num_element_value_pairs;
1896 calc_num_element_value_pairs++) {
1897 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1898 // not enough room for another element_name_index, let alone
1899 // the rest of another component
1900 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1901 ("length() is too small for element_name_index"));
1902 return false;
1903 }
1904
1905 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1906 annotations_typeArray, byte_i_ref,
1907 "mapped old element_name_index=%d", THREAD);
1908
1909 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1910 ("element_name_index=%d", element_name_index));
1911
1912 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1913 byte_i_ref, THREAD)) {
1914 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1915 ("bad element_value at %d", calc_num_element_value_pairs));
1916 // propagate failure back to caller
1917 return false;
1918 }
1919 } // end for each component
1920 assert(num_element_value_pairs == calc_num_element_value_pairs,
1921 "sanity check");
1922
1923 return true;
1924 } // end rewrite_cp_refs_in_annotation_struct()
1925
1926
1927 // Rewrite a constant pool reference at the current position in
1928 // annotations_typeArray if needed. Returns the original constant
1929 // pool reference if a rewrite was not needed or the new constant
1930 // pool reference if a rewrite was needed.
1931 PRAGMA_DIAG_PUSH
1932 PRAGMA_FORMAT_NONLITERAL_IGNORED
1933 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1934 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1935 const char * trace_mesg, TRAPS) {
1936
1937 address cp_index_addr = (address)
1938 annotations_typeArray->adr_at(byte_i_ref);
1939 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1940 u2 new_cp_index = find_new_index(old_cp_index);
1941 if (new_cp_index != 0) {
1942 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1943 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1944 old_cp_index = new_cp_index;
1945 }
1946 byte_i_ref += 2;
1947 return old_cp_index;
1948 }
1949 PRAGMA_DIAG_POP
1950
1951
1952 // Rewrite constant pool references in the element_value portion of an
1953 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1954 // the 2nd-edition of the VM spec:
1955 //
1956 // struct element_value {
1957 // u1 tag;
1958 // union {
1959 // u2 const_value_index;
1960 // {
1961 // u2 type_name_index;
1962 // u2 const_name_index;
1963 // } enum_const_value;
1964 // u2 class_info_index;
1965 // annotation annotation_value;
1966 // struct {
1967 // u2 num_values;
1968 // element_value values[num_values];
1969 // } array_value;
1970 // } value;
1971 // }
1972 //
1973 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1974 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1975
1976 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1977 // not enough room for a tag let alone the rest of an element_value
1978 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1979 ("length() is too small for a tag"));
1980 return false;
1981 }
1982
1983 u1 tag = annotations_typeArray->at(byte_i_ref);
1984 byte_i_ref++;
1985 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1986
1987 switch (tag) {
1988 // These BaseType tag values are from Table 4.2 in VM spec:
1989 case 'B': // byte
1990 case 'C': // char
1991 case 'D': // double
1992 case 'F': // float
1993 case 'I': // int
1994 case 'J': // long
1995 case 'S': // short
1996 case 'Z': // boolean
1997
1998 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1999 // the VM spec:
2000 case 's':
2001 {
2002 // For the above tag values (including the BaseType values),
2003 // value.const_value_index is right union field.
2004
2005 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2006 // not enough room for a const_value_index
2007 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2008 ("length() is too small for a const_value_index"));
2009 return false;
2010 }
2011
2012 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2013 annotations_typeArray, byte_i_ref,
2014 "mapped old const_value_index=%d", THREAD);
2015
2016 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2017 ("const_value_index=%d", const_value_index));
2018 } break;
2019
2020 case 'e':
2021 {
2022 // for the above tag value, value.enum_const_value is right union field
2023
2024 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2025 // not enough room for a enum_const_value
2026 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2027 ("length() is too small for a enum_const_value"));
2028 return false;
2029 }
2030
2031 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2032 annotations_typeArray, byte_i_ref,
2033 "mapped old type_name_index=%d", THREAD);
2034
2035 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2036 annotations_typeArray, byte_i_ref,
2037 "mapped old const_name_index=%d", THREAD);
2038
2039 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2040 ("type_name_index=%d const_name_index=%d", type_name_index,
2041 const_name_index));
2042 } break;
2043
2044 case 'c':
2045 {
2046 // for the above tag value, value.class_info_index is right union field
2047
2048 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2049 // not enough room for a class_info_index
2050 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2051 ("length() is too small for a class_info_index"));
2052 return false;
2053 }
2054
2055 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2056 annotations_typeArray, byte_i_ref,
2057 "mapped old class_info_index=%d", THREAD);
2058
2059 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2060 ("class_info_index=%d", class_info_index));
2061 } break;
2062
2063 case '@':
2064 // For the above tag value, value.attr_value is the right union
2065 // field. This is a nested annotation.
2066 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2067 byte_i_ref, THREAD)) {
2068 // propagate failure back to caller
2069 return false;
2070 }
2071 break;
2072
2073 case '[':
2074 {
2075 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2076 // not enough room for a num_values field
2077 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2078 ("length() is too small for a num_values field"));
2079 return false;
2080 }
2081
2082 // For the above tag value, value.array_value is the right union
2083 // field. This is an array of nested element_value.
2084 u2 num_values = Bytes::get_Java_u2((address)
2085 annotations_typeArray->adr_at(byte_i_ref));
2086 byte_i_ref += 2;
2087 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2088
2089 int calc_num_values = 0;
2090 for (; calc_num_values < num_values; calc_num_values++) {
2091 if (!rewrite_cp_refs_in_element_value(
2092 annotations_typeArray, byte_i_ref, THREAD)) {
2093 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2094 ("bad nested element_value at %d", calc_num_values));
2095 // propagate failure back to caller
2096 return false;
2097 }
2098 }
2099 assert(num_values == calc_num_values, "sanity check");
2100 } break;
2101
2102 default:
2103 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2104 return false;
2105 } // end decode tag field
2106
2107 return true;
2108 } // end rewrite_cp_refs_in_element_value()
2109
2110
2111 // Rewrite constant pool references in a fields_annotations field.
2112 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2113 instanceKlassHandle scratch_class, TRAPS) {
2114
2115 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2116
2117 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2118 // no fields_annotations so nothing to do
2119 return true;
2120 }
2121
2122 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2123 ("fields_annotations length=%d", fields_annotations->length()));
2124
2125 for (int i = 0; i < fields_annotations->length(); i++) {
2126 AnnotationArray* field_annotations = fields_annotations->at(i);
2127 if (field_annotations == NULL || field_annotations->length() == 0) {
2128 // this field does not have any annotations so skip it
2129 continue;
2130 }
2131
2132 int byte_i = 0; // byte index into field_annotations
2133 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2134 THREAD)) {
2135 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2136 ("bad field_annotations at %d", i));
2137 // propagate failure back to caller
2138 return false;
2139 }
2140 }
2141
2142 return true;
2143 } // end rewrite_cp_refs_in_fields_annotations()
2144
2145
2146 // Rewrite constant pool references in a methods_annotations field.
2147 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2148 instanceKlassHandle scratch_class, TRAPS) {
2149
2150 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2151 Method* m = scratch_class->methods()->at(i);
2152 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2153
2154 if (method_annotations == NULL || method_annotations->length() == 0) {
2155 // this method does not have any annotations so skip it
2156 continue;
2157 }
2158
2159 int byte_i = 0; // byte index into method_annotations
2160 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2161 THREAD)) {
2162 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2163 ("bad method_annotations at %d", i));
2164 // propagate failure back to caller
2165 return false;
2166 }
2167 }
2168
2169 return true;
2170 } // end rewrite_cp_refs_in_methods_annotations()
2171
2172
2173 // Rewrite constant pool references in a methods_parameter_annotations
2174 // field. This "structure" is adapted from the
2175 // RuntimeVisibleParameterAnnotations_attribute described in section
2176 // 4.8.17 of the 2nd-edition of the VM spec:
2177 //
2178 // methods_parameter_annotations_typeArray {
2179 // u1 num_parameters;
2180 // {
2181 // u2 num_annotations;
2182 // annotation annotations[num_annotations];
2183 // } parameter_annotations[num_parameters];
2184 // }
2185 //
2186 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2187 instanceKlassHandle scratch_class, TRAPS) {
2188
2189 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2190 Method* m = scratch_class->methods()->at(i);
2191 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2192 if (method_parameter_annotations == NULL
2193 || method_parameter_annotations->length() == 0) {
2194 // this method does not have any parameter annotations so skip it
2195 continue;
2196 }
2197
2198 if (method_parameter_annotations->length() < 1) {
2199 // not enough room for a num_parameters field
2200 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2201 ("length() is too small for a num_parameters field at %d", i));
2202 return false;
2203 }
2204
2205 int byte_i = 0; // byte index into method_parameter_annotations
2206
2207 u1 num_parameters = method_parameter_annotations->at(byte_i);
2208 byte_i++;
2209
2210 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2211 ("num_parameters=%d", num_parameters));
2212
2213 int calc_num_parameters = 0;
2214 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2215 if (!rewrite_cp_refs_in_annotations_typeArray(
2216 method_parameter_annotations, byte_i, THREAD)) {
2217 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2218 ("bad method_parameter_annotations at %d", calc_num_parameters));
2219 // propagate failure back to caller
2220 return false;
2221 }
2222 }
2223 assert(num_parameters == calc_num_parameters, "sanity check");
2224 }
2225
2226 return true;
2227 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2228
2229
2230 // Rewrite constant pool references in a methods_default_annotations
2231 // field. This "structure" is adapted from the AnnotationDefault_attribute
2232 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2233 //
2234 // methods_default_annotations_typeArray {
2235 // element_value default_value;
2236 // }
2237 //
2238 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2239 instanceKlassHandle scratch_class, TRAPS) {
2240
2241 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2242 Method* m = scratch_class->methods()->at(i);
2243 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2244 if (method_default_annotations == NULL
2245 || method_default_annotations->length() == 0) {
2246 // this method does not have any default annotations so skip it
2247 continue;
2248 }
2249
2250 int byte_i = 0; // byte index into method_default_annotations
2251
2252 if (!rewrite_cp_refs_in_element_value(
2253 method_default_annotations, byte_i, THREAD)) {
2254 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2255 ("bad default element_value at %d", i));
2256 // propagate failure back to caller
2257 return false;
2258 }
2259 }
2260
2261 return true;
2262 } // end rewrite_cp_refs_in_methods_default_annotations()
2263
2264
2265 // Rewrite constant pool references in a class_type_annotations field.
2266 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2267 instanceKlassHandle scratch_class, TRAPS) {
2268
2269 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2270 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2271 // no class_type_annotations so nothing to do
2272 return true;
2273 }
2274
2275 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2276 ("class_type_annotations length=%d", class_type_annotations->length()));
2277
2278 int byte_i = 0; // byte index into class_type_annotations
2279 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2280 byte_i, "ClassFile", THREAD);
2281 } // end rewrite_cp_refs_in_class_type_annotations()
2282
2283
2284 // Rewrite constant pool references in a fields_type_annotations field.
2285 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2286 instanceKlassHandle scratch_class, TRAPS) {
2287
2288 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2289 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2290 // no fields_type_annotations so nothing to do
2291 return true;
2292 }
2293
2294 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2295 ("fields_type_annotations length=%d", fields_type_annotations->length()));
2296
2297 for (int i = 0; i < fields_type_annotations->length(); i++) {
2298 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2299 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2300 // this field does not have any annotations so skip it
2301 continue;
2302 }
2303
2304 int byte_i = 0; // byte index into field_type_annotations
2305 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2306 byte_i, "field_info", THREAD)) {
2307 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2308 ("bad field_type_annotations at %d", i));
2309 // propagate failure back to caller
2310 return false;
2311 }
2312 }
2313
2314 return true;
2315 } // end rewrite_cp_refs_in_fields_type_annotations()
2316
2317
2318 // Rewrite constant pool references in a methods_type_annotations field.
2319 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2320 instanceKlassHandle scratch_class, TRAPS) {
2321
2322 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2323 Method* m = scratch_class->methods()->at(i);
2324 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2325
2326 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2327 // this method does not have any annotations so skip it
2328 continue;
2329 }
2330
2331 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2332 ("methods type_annotations length=%d", method_type_annotations->length()));
2333
2334 int byte_i = 0; // byte index into method_type_annotations
2335 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2336 byte_i, "method_info", THREAD)) {
2337 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2338 ("bad method_type_annotations at %d", i));
2339 // propagate failure back to caller
2340 return false;
2341 }
2342 }
2343
2344 return true;
2345 } // end rewrite_cp_refs_in_methods_type_annotations()
2346
2347
2348 // Rewrite constant pool references in a type_annotations
2349 // field. This "structure" is adapted from the
2350 // RuntimeVisibleTypeAnnotations_attribute described in
2351 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2352 //
2353 // type_annotations_typeArray {
2354 // u2 num_annotations;
2355 // type_annotation annotations[num_annotations];
2356 // }
2357 //
2358 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2359 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2360 const char * location_mesg, TRAPS) {
2361
2362 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2363 // not enough room for num_annotations field
2364 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2365 ("length() is too small for num_annotations field"));
2366 return false;
2367 }
2368
2369 u2 num_annotations = Bytes::get_Java_u2((address)
2370 type_annotations_typeArray->adr_at(byte_i_ref));
2371 byte_i_ref += 2;
2372
2373 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2374 ("num_type_annotations=%d", num_annotations));
2375
2376 int calc_num_annotations = 0;
2377 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2378 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2379 byte_i_ref, location_mesg, THREAD)) {
2380 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2381 ("bad type_annotation_struct at %d", calc_num_annotations));
2382 // propagate failure back to caller
2383 return false;
2384 }
2385 }
2386 assert(num_annotations == calc_num_annotations, "sanity check");
2387
2388 if (byte_i_ref != type_annotations_typeArray->length()) {
2389 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2390 ("read wrong amount of bytes at end of processing "
2391 "type_annotations_typeArray (%d of %d bytes were read)",
2392 byte_i_ref, type_annotations_typeArray->length()));
2393 return false;
2394 }
2395
2396 return true;
2397 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2398
2399
2400 // Rewrite constant pool references in a type_annotation
2401 // field. This "structure" is adapted from the
2402 // RuntimeVisibleTypeAnnotations_attribute described in
2403 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2404 //
2405 // type_annotation {
2406 // u1 target_type;
2407 // union {
2408 // type_parameter_target;
2409 // supertype_target;
2410 // type_parameter_bound_target;
2411 // empty_target;
2412 // method_formal_parameter_target;
2413 // throws_target;
2414 // localvar_target;
2415 // catch_target;
2416 // offset_target;
2417 // type_argument_target;
2418 // } target_info;
2419 // type_path target_path;
2420 // annotation anno;
2421 // }
2422 //
2423 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2424 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2425 const char * location_mesg, TRAPS) {
2426
2427 if (!skip_type_annotation_target(type_annotations_typeArray,
2428 byte_i_ref, location_mesg, THREAD)) {
2429 return false;
2430 }
2431
2432 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2433 byte_i_ref, THREAD)) {
2434 return false;
2435 }
2436
2437 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2438 byte_i_ref, THREAD)) {
2439 return false;
2440 }
2441
2442 return true;
2443 } // end rewrite_cp_refs_in_type_annotation_struct()
2444
2445
2446 // Read, verify and skip over the target_type and target_info part
2447 // so that rewriting can continue in the later parts of the struct.
2448 //
2449 // u1 target_type;
2450 // union {
2451 // type_parameter_target;
2452 // supertype_target;
2453 // type_parameter_bound_target;
2454 // empty_target;
2455 // method_formal_parameter_target;
2456 // throws_target;
2457 // localvar_target;
2458 // catch_target;
2459 // offset_target;
2460 // type_argument_target;
2461 // } target_info;
2462 //
2463 bool VM_RedefineClasses::skip_type_annotation_target(
2464 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2465 const char * location_mesg, TRAPS) {
2466
2467 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2468 // not enough room for a target_type let alone the rest of a type_annotation
2469 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2470 ("length() is too small for a target_type"));
2471 return false;
2472 }
2473
2474 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2475 byte_i_ref += 1;
2476 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type));
2477 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg));
2478
2479 // Skip over target_info
2480 switch (target_type) {
2481 case 0x00:
2482 // kind: type parameter declaration of generic class or interface
2483 // location: ClassFile
2484 case 0x01:
2485 // kind: type parameter declaration of generic method or constructor
2486 // location: method_info
2487
2488 {
2489 // struct:
2490 // type_parameter_target {
2491 // u1 type_parameter_index;
2492 // }
2493 //
2494 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2495 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2496 ("length() is too small for a type_parameter_target"));
2497 return false;
2498 }
2499
2500 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2501 byte_i_ref += 1;
2502
2503 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2504 ("type_parameter_target: type_parameter_index=%d",
2505 type_parameter_index));
2506 } break;
2507
2508 case 0x10:
2509 // kind: type in extends clause of class or interface declaration
2510 // (including the direct superclass of an anonymous class declaration),
2511 // or in implements clause of interface declaration
2512 // location: ClassFile
2513
2514 {
2515 // struct:
2516 // supertype_target {
2517 // u2 supertype_index;
2518 // }
2519 //
2520 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2521 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2522 ("length() is too small for a supertype_target"));
2523 return false;
2524 }
2525
2526 u2 supertype_index = Bytes::get_Java_u2((address)
2527 type_annotations_typeArray->adr_at(byte_i_ref));
2528 byte_i_ref += 2;
2529
2530 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2531 ("supertype_target: supertype_index=%d", supertype_index));
2532 } break;
2533
2534 case 0x11:
2535 // kind: type in bound of type parameter declaration of generic class or interface
2536 // location: ClassFile
2537 case 0x12:
2538 // kind: type in bound of type parameter declaration of generic method or constructor
2539 // location: method_info
2540
2541 {
2542 // struct:
2543 // type_parameter_bound_target {
2544 // u1 type_parameter_index;
2545 // u1 bound_index;
2546 // }
2547 //
2548 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2549 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2550 ("length() is too small for a type_parameter_bound_target"));
2551 return false;
2552 }
2553
2554 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2555 byte_i_ref += 1;
2556 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2557 byte_i_ref += 1;
2558
2559 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2560 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d",
2561 type_parameter_index, bound_index));
2562 } break;
2563
2564 case 0x13:
2565 // kind: type in field declaration
2566 // location: field_info
2567 case 0x14:
2568 // kind: return type of method, or type of newly constructed object
2569 // location: method_info
2570 case 0x15:
2571 // kind: receiver type of method or constructor
2572 // location: method_info
2573
2574 {
2575 // struct:
2576 // empty_target {
2577 // }
2578 //
2579 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2580 ("empty_target"));
2581 } break;
2582
2583 case 0x16:
2584 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2585 // location: method_info
2586
2587 {
2588 // struct:
2589 // formal_parameter_target {
2590 // u1 formal_parameter_index;
2591 // }
2592 //
2593 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2594 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2595 ("length() is too small for a formal_parameter_target"));
2596 return false;
2597 }
2598
2599 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2600 byte_i_ref += 1;
2601
2602 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2603 ("formal_parameter_target: formal_parameter_index=%d",
2604 formal_parameter_index));
2605 } break;
2606
2607 case 0x17:
2608 // kind: type in throws clause of method or constructor
2609 // location: method_info
2610
2611 {
2612 // struct:
2613 // throws_target {
2614 // u2 throws_type_index
2615 // }
2616 //
2617 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2618 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2619 ("length() is too small for a throws_target"));
2620 return false;
2621 }
2622
2623 u2 throws_type_index = Bytes::get_Java_u2((address)
2624 type_annotations_typeArray->adr_at(byte_i_ref));
2625 byte_i_ref += 2;
2626
2627 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2628 ("throws_target: throws_type_index=%d", throws_type_index));
2629 } break;
2630
2631 case 0x40:
2632 // kind: type in local variable declaration
2633 // location: Code
2634 case 0x41:
2635 // kind: type in resource variable declaration
2636 // location: Code
2637
2638 {
2639 // struct:
2640 // localvar_target {
2641 // u2 table_length;
2642 // struct {
2643 // u2 start_pc;
2644 // u2 length;
2645 // u2 index;
2646 // } table[table_length];
2647 // }
2648 //
2649 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2650 // not enough room for a table_length let alone the rest of a localvar_target
2651 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2652 ("length() is too small for a localvar_target table_length"));
2653 return false;
2654 }
2655
2656 u2 table_length = Bytes::get_Java_u2((address)
2657 type_annotations_typeArray->adr_at(byte_i_ref));
2658 byte_i_ref += 2;
2659
2660 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2661 ("localvar_target: table_length=%d", table_length));
2662
2663 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2664 int table_size = table_length * table_struct_size;
2665
2666 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2667 // not enough room for a table
2668 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2669 ("length() is too small for a table array of length %d", table_length));
2670 return false;
2671 }
2672
2673 // Skip over table
2674 byte_i_ref += table_size;
2675 } break;
2676
2677 case 0x42:
2678 // kind: type in exception parameter declaration
2679 // location: Code
2680
2681 {
2682 // struct:
2683 // catch_target {
2684 // u2 exception_table_index;
2685 // }
2686 //
2687 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2688 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2689 ("length() is too small for a catch_target"));
2690 return false;
2691 }
2692
2693 u2 exception_table_index = Bytes::get_Java_u2((address)
2694 type_annotations_typeArray->adr_at(byte_i_ref));
2695 byte_i_ref += 2;
2696
2697 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2698 ("catch_target: exception_table_index=%d", exception_table_index));
2699 } break;
2700
2701 case 0x43:
2702 // kind: type in instanceof expression
2703 // location: Code
2704 case 0x44:
2705 // kind: type in new expression
2706 // location: Code
2707 case 0x45:
2708 // kind: type in method reference expression using ::new
2709 // location: Code
2710 case 0x46:
2711 // kind: type in method reference expression using ::Identifier
2712 // location: Code
2713
2714 {
2715 // struct:
2716 // offset_target {
2717 // u2 offset;
2718 // }
2719 //
2720 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2721 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2722 ("length() is too small for a offset_target"));
2723 return false;
2724 }
2725
2726 u2 offset = Bytes::get_Java_u2((address)
2727 type_annotations_typeArray->adr_at(byte_i_ref));
2728 byte_i_ref += 2;
2729
2730 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2731 ("offset_target: offset=%d", offset));
2732 } break;
2733
2734 case 0x47:
2735 // kind: type in cast expression
2736 // location: Code
2737 case 0x48:
2738 // kind: type argument for generic constructor in new expression or
2739 // explicit constructor invocation statement
2740 // location: Code
2741 case 0x49:
2742 // kind: type argument for generic method in method invocation expression
2743 // location: Code
2744 case 0x4A:
2745 // kind: type argument for generic constructor in method reference expression using ::new
2746 // location: Code
2747 case 0x4B:
2748 // kind: type argument for generic method in method reference expression using ::Identifier
2749 // location: Code
2750
2751 {
2752 // struct:
2753 // type_argument_target {
2754 // u2 offset;
2755 // u1 type_argument_index;
2756 // }
2757 //
2758 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2759 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2760 ("length() is too small for a type_argument_target"));
2761 return false;
2762 }
2763
2764 u2 offset = Bytes::get_Java_u2((address)
2765 type_annotations_typeArray->adr_at(byte_i_ref));
2766 byte_i_ref += 2;
2767 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2768 byte_i_ref += 1;
2769
2770 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2771 ("type_argument_target: offset=%d, type_argument_index=%d",
2772 offset, type_argument_index));
2773 } break;
2774
2775 default:
2776 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2777 ("unknown target_type"));
2778 #ifdef ASSERT
2779 ShouldNotReachHere();
2780 #endif
2781 return false;
2782 }
2783
2784 return true;
2785 } // end skip_type_annotation_target()
2786
2787
2788 // Read, verify and skip over the type_path part so that rewriting
2789 // can continue in the later parts of the struct.
2790 //
2791 // type_path {
2792 // u1 path_length;
2793 // {
2794 // u1 type_path_kind;
2795 // u1 type_argument_index;
2796 // } path[path_length];
2797 // }
2798 //
2799 bool VM_RedefineClasses::skip_type_annotation_type_path(
2800 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2801
2802 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2803 // not enough room for a path_length let alone the rest of the type_path
2804 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2805 ("length() is too small for a type_path"));
2806 return false;
2807 }
2808
2809 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2810 byte_i_ref += 1;
2811
2812 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2813 ("type_path: path_length=%d", path_length));
2814
2815 int calc_path_length = 0;
2816 for (; calc_path_length < path_length; calc_path_length++) {
2817 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2818 // not enough room for a path
2819 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2820 ("length() is too small for path entry %d of %d",
2821 calc_path_length, path_length));
2822 return false;
2823 }
2824
2825 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2826 byte_i_ref += 1;
2827 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2828 byte_i_ref += 1;
2829
2830 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2831 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2832 calc_path_length, type_path_kind, type_argument_index));
2833
2834 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2835 // not enough room for a path
2836 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2837 ("inconsistent type_path values"));
2838 return false;
2839 }
2840 }
2841 assert(path_length == calc_path_length, "sanity check");
2842
2843 return true;
2844 } // end skip_type_annotation_type_path()
2845
2846
2847 // Rewrite constant pool references in the method's stackmap table.
2848 // These "structures" are adapted from the StackMapTable_attribute that
2849 // is described in section 4.8.4 of the 6.0 version of the VM spec
2850 // (dated 2005.10.26):
2851 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2852 //
2853 // stack_map {
2854 // u2 number_of_entries;
2855 // stack_map_frame entries[number_of_entries];
2856 // }
2857 //
2858 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2859 methodHandle method, TRAPS) {
2860
2861 if (!method->has_stackmap_table()) {
2862 return;
2863 }
2864
2865 AnnotationArray* stackmap_data = method->stackmap_data();
2866 address stackmap_p = (address)stackmap_data->adr_at(0);
2867 address stackmap_end = stackmap_p + stackmap_data->length();
2868
2869 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2870 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2871 stackmap_p += 2;
2872
2873 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2874 ("number_of_entries=%u", number_of_entries));
2875
2876 // walk through each stack_map_frame
2877 u2 calc_number_of_entries = 0;
2878 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2879 // The stack_map_frame structure is a u1 frame_type followed by
2880 // 0 or more bytes of data:
2881 //
2882 // union stack_map_frame {
2883 // same_frame;
2884 // same_locals_1_stack_item_frame;
2885 // same_locals_1_stack_item_frame_extended;
2886 // chop_frame;
2887 // same_frame_extended;
2888 // append_frame;
2889 // full_frame;
2890 // }
2891
2892 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2893 // The Linux compiler does not like frame_type to be u1 or u2. It
2894 // issues the following warning for the first if-statement below:
2895 //
2896 // "warning: comparison is always true due to limited range of data type"
2897 //
2898 u4 frame_type = *stackmap_p;
2899 stackmap_p++;
2900
2901 // same_frame {
2902 // u1 frame_type = SAME; /* 0-63 */
2903 // }
2904 if (frame_type >= 0 && frame_type <= 63) {
2905 // nothing more to do for same_frame
2906 }
2907
2908 // same_locals_1_stack_item_frame {
2909 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2910 // verification_type_info stack[1];
2911 // }
2912 else if (frame_type >= 64 && frame_type <= 127) {
2913 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2914 calc_number_of_entries, frame_type, THREAD);
2915 }
2916
2917 // reserved for future use
2918 else if (frame_type >= 128 && frame_type <= 246) {
2919 // nothing more to do for reserved frame_types
2920 }
2921
2922 // same_locals_1_stack_item_frame_extended {
2923 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2924 // u2 offset_delta;
2925 // verification_type_info stack[1];
2926 // }
2927 else if (frame_type == 247) {
2928 stackmap_p += 2;
2929 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2930 calc_number_of_entries, frame_type, THREAD);
2931 }
2932
2933 // chop_frame {
2934 // u1 frame_type = CHOP; /* 248-250 */
2935 // u2 offset_delta;
2936 // }
2937 else if (frame_type >= 248 && frame_type <= 250) {
2938 stackmap_p += 2;
2939 }
2940
2941 // same_frame_extended {
2942 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2943 // u2 offset_delta;
2944 // }
2945 else if (frame_type == 251) {
2946 stackmap_p += 2;
2947 }
2948
2949 // append_frame {
2950 // u1 frame_type = APPEND; /* 252-254 */
2951 // u2 offset_delta;
2952 // verification_type_info locals[frame_type - 251];
2953 // }
2954 else if (frame_type >= 252 && frame_type <= 254) {
2955 assert(stackmap_p + 2 <= stackmap_end,
2956 "no room for offset_delta");
2957 stackmap_p += 2;
2958 u1 len = frame_type - 251;
2959 for (u1 i = 0; i < len; i++) {
2960 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2961 calc_number_of_entries, frame_type, THREAD);
2962 }
2963 }
2964
2965 // full_frame {
2966 // u1 frame_type = FULL_FRAME; /* 255 */
2967 // u2 offset_delta;
2968 // u2 number_of_locals;
2969 // verification_type_info locals[number_of_locals];
2970 // u2 number_of_stack_items;
2971 // verification_type_info stack[number_of_stack_items];
2972 // }
2973 else if (frame_type == 255) {
2974 assert(stackmap_p + 2 + 2 <= stackmap_end,
2975 "no room for smallest full_frame");
2976 stackmap_p += 2;
2977
2978 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2979 stackmap_p += 2;
2980
2981 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2982 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2983 calc_number_of_entries, frame_type, THREAD);
2984 }
2985
2986 // Use the largest size for the number_of_stack_items, but only get
2987 // the right number of bytes.
2988 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2989 stackmap_p += 2;
2990
2991 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2992 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2993 calc_number_of_entries, frame_type, THREAD);
2994 }
2995 }
2996 } // end while there is a stack_map_frame
2997 assert(number_of_entries == calc_number_of_entries, "sanity check");
2998 } // end rewrite_cp_refs_in_stack_map_table()
2999
3000
3001 // Rewrite constant pool references in the verification type info
3002 // portion of the method's stackmap table. These "structures" are
3003 // adapted from the StackMapTable_attribute that is described in
3004 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3005 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3006 //
3007 // The verification_type_info structure is a u1 tag followed by 0 or
3008 // more bytes of data:
3009 //
3010 // union verification_type_info {
3011 // Top_variable_info;
3012 // Integer_variable_info;
3013 // Float_variable_info;
3014 // Long_variable_info;
3015 // Double_variable_info;
3016 // Null_variable_info;
3017 // UninitializedThis_variable_info;
3018 // Object_variable_info;
3019 // Uninitialized_variable_info;
3020 // }
3021 //
3022 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3023 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3024 u1 frame_type, TRAPS) {
3025
3026 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3027 u1 tag = *stackmap_p_ref;
3028 stackmap_p_ref++;
3029
3030 switch (tag) {
3031 // Top_variable_info {
3032 // u1 tag = ITEM_Top; /* 0 */
3033 // }
3034 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3035 case 0: // fall through
3036
3037 // Integer_variable_info {
3038 // u1 tag = ITEM_Integer; /* 1 */
3039 // }
3040 case ITEM_Integer: // fall through
3041
3042 // Float_variable_info {
3043 // u1 tag = ITEM_Float; /* 2 */
3044 // }
3045 case ITEM_Float: // fall through
3046
3047 // Double_variable_info {
3048 // u1 tag = ITEM_Double; /* 3 */
3049 // }
3050 case ITEM_Double: // fall through
3051
3052 // Long_variable_info {
3053 // u1 tag = ITEM_Long; /* 4 */
3054 // }
3055 case ITEM_Long: // fall through
3056
3057 // Null_variable_info {
3058 // u1 tag = ITEM_Null; /* 5 */
3059 // }
3060 case ITEM_Null: // fall through
3061
3062 // UninitializedThis_variable_info {
3063 // u1 tag = ITEM_UninitializedThis; /* 6 */
3064 // }
3065 case ITEM_UninitializedThis:
3066 // nothing more to do for the above tag types
3067 break;
3068
3069 // Object_variable_info {
3070 // u1 tag = ITEM_Object; /* 7 */
3071 // u2 cpool_index;
3072 // }
3073 case ITEM_Object:
3074 {
3075 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3076 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3077 u2 new_cp_index = find_new_index(cpool_index);
3078 if (new_cp_index != 0) {
3079 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3080 ("mapped old cpool_index=%d", cpool_index));
3081 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3082 cpool_index = new_cp_index;
3083 }
3084 stackmap_p_ref += 2;
3085
3086 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3087 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
3088 frame_type, cpool_index));
3089 } break;
3090
3091 // Uninitialized_variable_info {
3092 // u1 tag = ITEM_Uninitialized; /* 8 */
3093 // u2 offset;
3094 // }
3095 case ITEM_Uninitialized:
3096 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3097 stackmap_p_ref += 2;
3098 break;
3099
3100 default:
3101 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3102 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
3103 ShouldNotReachHere();
3104 break;
3105 } // end switch (tag)
3106 } // end rewrite_cp_refs_in_verification_type_info()
3107
3108
3109 // Change the constant pool associated with klass scratch_class to
3110 // scratch_cp. If shrink is true, then scratch_cp_length elements
3111 // are copied from scratch_cp to a smaller constant pool and the
3112 // smaller constant pool is associated with scratch_class.
3113 void VM_RedefineClasses::set_new_constant_pool(
3114 ClassLoaderData* loader_data,
3115 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
3116 int scratch_cp_length, TRAPS) {
3117 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3118
3119 // scratch_cp is a merged constant pool and has enough space for a
3120 // worst case merge situation. We want to associate the minimum
3121 // sized constant pool with the klass to save space.
3122 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3123 constantPoolHandle smaller_cp(THREAD, cp);
3124
3125 // preserve version() value in the smaller copy
3126 int version = scratch_cp->version();
3127 assert(version != 0, "sanity check");
3128 smaller_cp->set_version(version);
3129
3130 // attach klass to new constant pool
3131 // reference to the cp holder is needed for copy_operands()
3132 smaller_cp->set_pool_holder(scratch_class());
3133
3134 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3135 if (HAS_PENDING_EXCEPTION) {
3136 // Exception is handled in the caller
3137 loader_data->add_to_deallocate_list(smaller_cp());
3138 return;
3139 }
3140 scratch_cp = smaller_cp;
3141
3142 // attach new constant pool to klass
3143 scratch_class->set_constants(scratch_cp());
3144
3145 int i; // for portability
3146
3147 // update each field in klass to use new constant pool indices as needed
3148 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3149 jshort cur_index = fs.name_index();
3150 jshort new_index = find_new_index(cur_index);
3151 if (new_index != 0) {
3152 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3153 ("field-name_index change: %d to %d", cur_index, new_index));
3154 fs.set_name_index(new_index);
3155 }
3156 cur_index = fs.signature_index();
3157 new_index = find_new_index(cur_index);
3158 if (new_index != 0) {
3159 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3160 ("field-signature_index change: %d to %d", cur_index, new_index));
3161 fs.set_signature_index(new_index);
3162 }
3163 cur_index = fs.initval_index();
3164 new_index = find_new_index(cur_index);
3165 if (new_index != 0) {
3166 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3167 ("field-initval_index change: %d to %d", cur_index, new_index));
3168 fs.set_initval_index(new_index);
3169 }
3170 cur_index = fs.generic_signature_index();
3171 new_index = find_new_index(cur_index);
3172 if (new_index != 0) {
3173 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3174 ("field-generic_signature change: %d to %d", cur_index, new_index));
3175 fs.set_generic_signature_index(new_index);
3176 }
3177 } // end for each field
3178
3179 // Update constant pool indices in the inner classes info to use
3180 // new constant indices as needed. The inner classes info is a
3181 // quadruple:
3182 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3183 InnerClassesIterator iter(scratch_class);
3184 for (; !iter.done(); iter.next()) {
3185 int cur_index = iter.inner_class_info_index();
3186 if (cur_index == 0) {
3187 continue; // JVM spec. allows null inner class refs so skip it
3188 }
3189 int new_index = find_new_index(cur_index);
3190 if (new_index != 0) {
3191 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3192 ("inner_class_info change: %d to %d", cur_index, new_index));
3193 iter.set_inner_class_info_index(new_index);
3194 }
3195 cur_index = iter.outer_class_info_index();
3196 new_index = find_new_index(cur_index);
3197 if (new_index != 0) {
3198 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3199 ("outer_class_info change: %d to %d", cur_index, new_index));
3200 iter.set_outer_class_info_index(new_index);
3201 }
3202 cur_index = iter.inner_name_index();
3203 new_index = find_new_index(cur_index);
3204 if (new_index != 0) {
3205 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3206 ("inner_name change: %d to %d", cur_index, new_index));
3207 iter.set_inner_name_index(new_index);
3208 }
3209 } // end for each inner class
3210
3211 // Attach each method in klass to the new constant pool and update
3212 // to use new constant pool indices as needed:
3213 Array<Method*>* methods = scratch_class->methods();
3214 for (i = methods->length() - 1; i >= 0; i--) {
3215 methodHandle method(THREAD, methods->at(i));
3216 method->set_constants(scratch_cp());
3217
3218 int new_index = find_new_index(method->name_index());
3219 if (new_index != 0) {
3220 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3221 ("method-name_index change: %d to %d", method->name_index(),
3222 new_index));
3223 method->set_name_index(new_index);
3224 }
3225 new_index = find_new_index(method->signature_index());
3226 if (new_index != 0) {
3227 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3228 ("method-signature_index change: %d to %d",
3229 method->signature_index(), new_index));
3230 method->set_signature_index(new_index);
3231 }
3232 new_index = find_new_index(method->generic_signature_index());
3233 if (new_index != 0) {
3234 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3235 ("method-generic_signature_index change: %d to %d",
3236 method->generic_signature_index(), new_index));
3237 method->set_generic_signature_index(new_index);
3238 }
3239
3240 // Update constant pool indices in the method's checked exception
3241 // table to use new constant indices as needed.
3242 int cext_length = method->checked_exceptions_length();
3243 if (cext_length > 0) {
3244 CheckedExceptionElement * cext_table =
3245 method->checked_exceptions_start();
3246 for (int j = 0; j < cext_length; j++) {
3247 int cur_index = cext_table[j].class_cp_index;
3248 int new_index = find_new_index(cur_index);
3249 if (new_index != 0) {
3250 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3251 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
3252 cext_table[j].class_cp_index = (u2)new_index;
3253 }
3254 } // end for each checked exception table entry
3255 } // end if there are checked exception table entries
3256
3257 // Update each catch type index in the method's exception table
3258 // to use new constant pool indices as needed. The exception table
3259 // holds quadruple entries of the form:
3260 // (beg_bci, end_bci, handler_bci, klass_index)
3261
3262 ExceptionTable ex_table(method());
3263 int ext_length = ex_table.length();
3264
3265 for (int j = 0; j < ext_length; j ++) {
3266 int cur_index = ex_table.catch_type_index(j);
3267 int new_index = find_new_index(cur_index);
3268 if (new_index != 0) {
3269 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3270 ("ext-klass_index change: %d to %d", cur_index, new_index));
3271 ex_table.set_catch_type_index(j, new_index);
3272 }
3273 } // end for each exception table entry
3274
3275 // Update constant pool indices in the method's local variable
3276 // table to use new constant indices as needed. The local variable
3277 // table hold sextuple entries of the form:
3278 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3279 int lvt_length = method->localvariable_table_length();
3280 if (lvt_length > 0) {
3281 LocalVariableTableElement * lv_table =
3282 method->localvariable_table_start();
3283 for (int j = 0; j < lvt_length; j++) {
3284 int cur_index = lv_table[j].name_cp_index;
3285 int new_index = find_new_index(cur_index);
3286 if (new_index != 0) {
3287 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3288 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
3289 lv_table[j].name_cp_index = (u2)new_index;
3290 }
3291 cur_index = lv_table[j].descriptor_cp_index;
3292 new_index = find_new_index(cur_index);
3293 if (new_index != 0) {
3294 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3295 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
3296 new_index));
3297 lv_table[j].descriptor_cp_index = (u2)new_index;
3298 }
3299 cur_index = lv_table[j].signature_cp_index;
3300 new_index = find_new_index(cur_index);
3301 if (new_index != 0) {
3302 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3303 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
3304 lv_table[j].signature_cp_index = (u2)new_index;
3305 }
3306 } // end for each local variable table entry
3307 } // end if there are local variable table entries
3308
3309 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3310 } // end for each method
3311 } // end set_new_constant_pool()
3312
3313
3314 // Unevolving classes may point to methods of the_class directly
3315 // from their constant pool caches, itables, and/or vtables. We
3316 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3317 // to fix up these pointers.
3318
3319 // Adjust cpools and vtables closure
3320 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3321
3322 // This is a very busy routine. We don't want too much tracing
3323 // printed out.
3324 bool trace_name_printed = false;
3325
3326 // Very noisy: only enable this call if you are trying to determine
3327 // that a specific class gets found by this routine.
3328 // RC_TRACE macro has an embedded ResourceMark
3329 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
3330 // ("adjust check: name=%s", k->external_name()));
3331 // trace_name_printed = true;
3332
3333 // If the class being redefined is java.lang.Object, we need to fix all
3334 // array class vtables also
3335 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
3336 k->vtable()->adjust_method_entries(_matching_old_methods,
3337 _matching_new_methods,
3338 _matching_methods_length,
3339 &trace_name_printed);
3340 } else if (k->oop_is_instance()) {
3341 HandleMark hm(_thread);
3342 InstanceKlass *ik = InstanceKlass::cast(k);
3343
3344 // HotSpot specific optimization! HotSpot does not currently
3345 // support delegation from the bootstrap class loader to a
3346 // user-defined class loader. This means that if the bootstrap
3347 // class loader is the initiating class loader, then it will also
3348 // be the defining class loader. This also means that classes
3349 // loaded by the bootstrap class loader cannot refer to classes
3350 // loaded by a user-defined class loader. Note: a user-defined
3351 // class loader can delegate to the bootstrap class loader.
3352 //
3353 // If the current class being redefined has a user-defined class
3354 // loader as its defining class loader, then we can skip all
3355 // classes loaded by the bootstrap class loader.
3356 bool is_user_defined =
3357 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
3358 if (is_user_defined && ik->class_loader() == NULL) {
3359 return;
3360 }
3361
3362 // Fix the vtable embedded in the_class and subclasses of the_class,
3363 // if one exists. We discard scratch_class and we don't keep an
3364 // InstanceKlass around to hold obsolete methods so we don't have
3365 // any other InstanceKlass embedded vtables to update. The vtable
3366 // holds the Method*s for virtual (but not final) methods.
3367 // Default methods, or concrete methods in interfaces are stored
3368 // in the vtable, so if an interface changes we need to check
3369 // adjust_method_entries() for every InstanceKlass, which will also
3370 // adjust the default method vtable indices.
3371 // We also need to adjust any default method entries that are
3372 // not yet in the vtable, because the vtable setup is in progress.
3373 // This must be done after we adjust the default_methods and
3374 // default_vtable_indices for methods already in the vtable.
3375 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
3376 || ik->is_subtype_of(_the_class_oop))) {
3377 // ik->vtable() creates a wrapper object; rm cleans it up
3378 ResourceMark rm(_thread);
3379 ik->vtable()->adjust_method_entries(_matching_old_methods,
3380 _matching_new_methods,
3381 _matching_methods_length,
3382 &trace_name_printed);
3383 ik->adjust_default_methods(_matching_old_methods,
3384 _matching_new_methods,
3385 _matching_methods_length,
3386 &trace_name_printed);
3387 }
3388
3389 // If the current class has an itable and we are either redefining an
3390 // interface or if the current class is a subclass of the_class, then
3391 // we potentially have to fix the itable. If we are redefining an
3392 // interface, then we have to call adjust_method_entries() for
3393 // every InstanceKlass that has an itable since there isn't a
3394 // subclass relationship between an interface and an InstanceKlass.
3395 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
3396 || ik->is_subclass_of(_the_class_oop))) {
3397 // ik->itable() creates a wrapper object; rm cleans it up
3398 ResourceMark rm(_thread);
3399 ik->itable()->adjust_method_entries(_matching_old_methods,
3400 _matching_new_methods,
3401 _matching_methods_length,
3402 &trace_name_printed);
3403 }
3404
3405 // The constant pools in other classes (other_cp) can refer to
3406 // methods in the_class. We have to update method information in
3407 // other_cp's cache. If other_cp has a previous version, then we
3408 // have to repeat the process for each previous version. The
3409 // constant pool cache holds the Method*s for non-virtual
3410 // methods and for virtual, final methods.
3411 //
3412 // Special case: if the current class is the_class, then new_cp
3413 // has already been attached to the_class and old_cp has already
3414 // been added as a previous version. The new_cp doesn't have any
3415 // cached references to old methods so it doesn't need to be
3416 // updated. We can simply start with the previous version(s) in
3417 // that case.
3418 constantPoolHandle other_cp;
3419 ConstantPoolCache* cp_cache;
3420
3421 if (ik != _the_class_oop) {
3422 // this klass' constant pool cache may need adjustment
3423 other_cp = constantPoolHandle(ik->constants());
3424 cp_cache = other_cp->cache();
3425 if (cp_cache != NULL) {
3426 cp_cache->adjust_method_entries(_matching_old_methods,
3427 _matching_new_methods,
3428 _matching_methods_length,
3429 &trace_name_printed);
3430 }
3431 }
3432
3433 // the previous versions' constant pool caches may need adjustment
3434 PreviousVersionWalker pvw(_thread, ik);
3435 for (PreviousVersionNode * pv_node = pvw.next_previous_version();
3436 pv_node != NULL; pv_node = pvw.next_previous_version()) {
3437 other_cp = pv_node->prev_constant_pool();
3438 cp_cache = other_cp->cache();
3439 if (cp_cache != NULL) {
3440 cp_cache->adjust_method_entries(_matching_old_methods,
3441 _matching_new_methods,
3442 _matching_methods_length,
3443 &trace_name_printed);
3444 }
3445 }
3446 }
3447 }
3448
3449 void VM_RedefineClasses::update_jmethod_ids() {
3450 for (int j = 0; j < _matching_methods_length; ++j) {
3451 Method* old_method = _matching_old_methods[j];
3452 jmethodID jmid = old_method->find_jmethod_id_or_null();
3453 if (jmid != NULL) {
3454 // There is a jmethodID, change it to point to the new method
3455 methodHandle new_method_h(_matching_new_methods[j]);
3456 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3457 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3458 "should be replaced");
3459 }
3460 }
3461 }
3462
3463 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
3464 BitMap *emcp_methods, int * emcp_method_count_p) {
3465 *emcp_method_count_p = 0;
3466 int obsolete_count = 0;
3467 int old_index = 0;
3468 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3469 Method* old_method = _matching_old_methods[j];
3470 Method* new_method = _matching_new_methods[j];
3471 Method* old_array_method;
3472
3473 // Maintain an old_index into the _old_methods array by skipping
3474 // deleted methods
3475 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3476 ++old_index;
3477 }
3478
3479 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3480 // The EMCP definition from JSR-163 requires the bytecodes to be
3481 // the same with the exception of constant pool indices which may
3482 // differ. However, the constants referred to by those indices
3483 // must be the same.
3484 //
3485 // We use methods_EMCP() for comparison since constant pool
3486 // merging can remove duplicate constant pool entries that were
3487 // present in the old method and removed from the rewritten new
3488 // method. A faster binary comparison function would consider the
3489 // old and new methods to be different when they are actually
3490 // EMCP.
3491 //
3492 // The old and new methods are EMCP and you would think that we
3493 // could get rid of one of them here and now and save some space.
3494 // However, the concept of EMCP only considers the bytecodes and
3495 // the constant pool entries in the comparison. Other things,
3496 // e.g., the line number table (LNT) or the local variable table
3497 // (LVT) don't count in the comparison. So the new (and EMCP)
3498 // method can have a new LNT that we need so we can't just
3499 // overwrite the new method with the old method.
3500 //
3501 // When this routine is called, we have already attached the new
3502 // methods to the_class so the old methods are effectively
3503 // overwritten. However, if an old method is still executing,
3504 // then the old method cannot be collected until sometime after
3505 // the old method call has returned. So the overwriting of old
3506 // methods by new methods will save us space except for those
3507 // (hopefully few) old methods that are still executing.
3508 //
3509 // A method refers to a ConstMethod* and this presents another
3510 // possible avenue to space savings. The ConstMethod* in the
3511 // new method contains possibly new attributes (LNT, LVT, etc).
3512 // At first glance, it seems possible to save space by replacing
3513 // the ConstMethod* in the old method with the ConstMethod*
3514 // from the new method. The old and new methods would share the
3515 // same ConstMethod* and we would save the space occupied by
3516 // the old ConstMethod*. However, the ConstMethod* contains
3517 // a back reference to the containing method. Sharing the
3518 // ConstMethod* between two methods could lead to confusion in
3519 // the code that uses the back reference. This would lead to
3520 // brittle code that could be broken in non-obvious ways now or
3521 // in the future.
3522 //
3523 // Another possibility is to copy the ConstMethod* from the new
3524 // method to the old method and then overwrite the new method with
3525 // the old method. Since the ConstMethod* contains the bytecodes
3526 // for the method embedded in the oop, this option would change
3527 // the bytecodes out from under any threads executing the old
3528 // method and make the thread's bcp invalid. Since EMCP requires
3529 // that the bytecodes be the same modulo constant pool indices, it
3530 // is straight forward to compute the correct new bcp in the new
3531 // ConstMethod* from the old bcp in the old ConstMethod*. The
3532 // time consuming part would be searching all the frames in all
3533 // of the threads to find all of the calls to the old method.
3534 //
3535 // It looks like we will have to live with the limited savings
3536 // that we get from effectively overwriting the old methods
3537 // when the new methods are attached to the_class.
3538
3539 // track which methods are EMCP for add_previous_version() call
3540 emcp_methods->set_bit(old_index);
3541 (*emcp_method_count_p)++;
3542
3543 // An EMCP method is _not_ obsolete. An obsolete method has a
3544 // different jmethodID than the current method. An EMCP method
3545 // has the same jmethodID as the current method. Having the
3546 // same jmethodID for all EMCP versions of a method allows for
3547 // a consistent view of the EMCP methods regardless of which
3548 // EMCP method you happen to have in hand. For example, a
3549 // breakpoint set in one EMCP method will work for all EMCP
3550 // versions of the method including the current one.
3551 } else {
3552 // mark obsolete methods as such
3553 old_method->set_is_obsolete();
3554 obsolete_count++;
3555
3556 // obsolete methods need a unique idnum so they become new entries in
3557 // the jmethodID cache in InstanceKlass
3558 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
3559 if (num != ConstMethod::UNSET_IDNUM) {
3560 old_method->set_method_idnum(num);
3561 }
3562
3563 // With tracing we try not to "yack" too much. The position of
3564 // this trace assumes there are fewer obsolete methods than
3565 // EMCP methods.
3566 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
3567 old_method->name()->as_C_string(),
3568 old_method->signature()->as_C_string()));
3569 }
3570 old_method->set_is_old();
3571 }
3572 for (int i = 0; i < _deleted_methods_length; ++i) {
3573 Method* old_method = _deleted_methods[i];
3574
3575 assert(!old_method->has_vtable_index(),
3576 "cannot delete methods with vtable entries");;
3577
3578 // Mark all deleted methods as old and obsolete
3579 old_method->set_is_old();
3580 old_method->set_is_obsolete();
3581 ++obsolete_count;
3582 // With tracing we try not to "yack" too much. The position of
3583 // this trace assumes there are fewer obsolete methods than
3584 // EMCP methods.
3585 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
3586 old_method->name()->as_C_string(),
3587 old_method->signature()->as_C_string()));
3588 }
3589 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
3590 "sanity check");
3591 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
3592 obsolete_count));
3593 }
3594
3595 // This internal class transfers the native function registration from old methods
3596 // to new methods. It is designed to handle both the simple case of unchanged
3597 // native methods and the complex cases of native method prefixes being added and/or
3598 // removed.
3599 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3600 //
3601 // This class is used after the new methods have been installed in "the_class".
3602 //
3603 // So, for example, the following must be handled. Where 'm' is a method and
3604 // a number followed by an underscore is a prefix.
3605 //
3606 // Old Name New Name
3607 // Simple transfer to new method m -> m
3608 // Add prefix m -> 1_m
3609 // Remove prefix 1_m -> m
3610 // Simultaneous add of prefixes m -> 3_2_1_m
3611 // Simultaneous removal of prefixes 3_2_1_m -> m
3612 // Simultaneous add and remove 1_m -> 2_m
3613 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3614 //
3615 class TransferNativeFunctionRegistration {
3616 private:
3617 instanceKlassHandle the_class;
3618 int prefix_count;
3619 char** prefixes;
3620
3621 // Recursively search the binary tree of possibly prefixed method names.
3622 // Iteration could be used if all agents were well behaved. Full tree walk is
3623 // more resilent to agents not cleaning up intermediate methods.
3624 // Branch at each depth in the binary tree is:
3625 // (1) without the prefix.
3626 // (2) with the prefix.
3627 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3628 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3629 Symbol* signature) {
3630 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3631 if (name_symbol != NULL) {
3632 Method* method = the_class()->lookup_method(name_symbol, signature);
3633 if (method != NULL) {
3634 // Even if prefixed, intermediate methods must exist.
3635 if (method->is_native()) {
3636 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3637 return method;
3638 }
3639 if (depth < prefix_count) {
3640 // Try applying further prefixes (other than this one).
3641 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3642 if (method != NULL) {
3643 return method; // found
3644 }
3645
3646 // Try adding this prefix to the method name and see if it matches
3647 // another method name.
3648 char* prefix = prefixes[depth];
3649 size_t prefix_len = strlen(prefix);
3650 size_t trial_len = name_len + prefix_len;
3651 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3652 strcpy(trial_name_str, prefix);
3653 strcat(trial_name_str, name_str);
3654 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3655 signature);
3656 if (method != NULL) {
3657 // If found along this branch, it was prefixed, mark as such
3658 method->set_is_prefixed_native();
3659 return method; // found
3660 }
3661 }
3662 }
3663 }
3664 return NULL; // This whole branch bore nothing
3665 }
3666
3667 // Return the method name with old prefixes stripped away.
3668 char* method_name_without_prefixes(Method* method) {
3669 Symbol* name = method->name();
3670 char* name_str = name->as_utf8();
3671
3672 // Old prefixing may be defunct, strip prefixes, if any.
3673 for (int i = prefix_count-1; i >= 0; i--) {
3674 char* prefix = prefixes[i];
3675 size_t prefix_len = strlen(prefix);
3676 if (strncmp(prefix, name_str, prefix_len) == 0) {
3677 name_str += prefix_len;
3678 }
3679 }
3680 return name_str;
3681 }
3682
3683 // Strip any prefixes off the old native method, then try to find a
3684 // (possibly prefixed) new native that matches it.
3685 Method* strip_and_search_for_new_native(Method* method) {
3686 ResourceMark rm;
3687 char* name_str = method_name_without_prefixes(method);
3688 return search_prefix_name_space(0, name_str, strlen(name_str),
3689 method->signature());
3690 }
3691
3692 public:
3693
3694 // Construct a native method transfer processor for this class.
3695 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3696 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3697
3698 the_class = _the_class;
3699 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3700 }
3701
3702 // Attempt to transfer any of the old or deleted methods that are native
3703 void transfer_registrations(Method** old_methods, int methods_length) {
3704 for (int j = 0; j < methods_length; j++) {
3705 Method* old_method = old_methods[j];
3706
3707 if (old_method->is_native() && old_method->has_native_function()) {
3708 Method* new_method = strip_and_search_for_new_native(old_method);
3709 if (new_method != NULL) {
3710 // Actually set the native function in the new method.
3711 // Redefine does not send events (except CFLH), certainly not this
3712 // behind the scenes re-registration.
3713 new_method->set_native_function(old_method->native_function(),
3714 !Method::native_bind_event_is_interesting);
3715 }
3716 }
3717 }
3718 }
3719 };
3720
3721 // Don't lose the association between a native method and its JNI function.
3722 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3723 TransferNativeFunctionRegistration transfer(the_class);
3724 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3725 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3726 }
3727
3728 // Deoptimize all compiled code that depends on this class.
3729 //
3730 // If the can_redefine_classes capability is obtained in the onload
3731 // phase then the compiler has recorded all dependencies from startup.
3732 // In that case we need only deoptimize and throw away all compiled code
3733 // that depends on the class.
3734 //
3735 // If can_redefine_classes is obtained sometime after the onload
3736 // phase then the dependency information may be incomplete. In that case
3737 // the first call to RedefineClasses causes all compiled code to be
3738 // thrown away. As can_redefine_classes has been obtained then
3739 // all future compilations will record dependencies so second and
3740 // subsequent calls to RedefineClasses need only throw away code
3741 // that depends on the class.
3742 //
3743 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3744 assert_locked_or_safepoint(Compile_lock);
3745
3746 // All dependencies have been recorded from startup or this is a second or
3747 // subsequent use of RedefineClasses
3748 if (JvmtiExport::all_dependencies_are_recorded()) {
3749 Universe::flush_evol_dependents_on(k_h);
3750 } else {
3751 CodeCache::mark_all_nmethods_for_deoptimization();
3752
3753 ResourceMark rm(THREAD);
3754 DeoptimizationMarker dm;
3755
3756 // Deoptimize all activations depending on marked nmethods
3757 Deoptimization::deoptimize_dependents();
3758
3759 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3760 CodeCache::make_marked_nmethods_not_entrant();
3761
3762 // From now on we know that the dependency information is complete
3763 JvmtiExport::set_all_dependencies_are_recorded(true);
3764 }
3765 }
3766
3767 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3768 Method* old_method;
3769 Method* new_method;
3770
3771 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3772 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3773 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3774 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3775
3776 _matching_methods_length = 0;
3777 _deleted_methods_length = 0;
3778 _added_methods_length = 0;
3779
3780 int nj = 0;
3781 int oj = 0;
3782 while (true) {
3783 if (oj >= _old_methods->length()) {
3784 if (nj >= _new_methods->length()) {
3785 break; // we've looked at everything, done
3786 }
3787 // New method at the end
3788 new_method = _new_methods->at(nj);
3789 _added_methods[_added_methods_length++] = new_method;
3790 ++nj;
3791 } else if (nj >= _new_methods->length()) {
3792 // Old method, at the end, is deleted
3793 old_method = _old_methods->at(oj);
3794 _deleted_methods[_deleted_methods_length++] = old_method;
3795 ++oj;
3796 } else {
3797 old_method = _old_methods->at(oj);
3798 new_method = _new_methods->at(nj);
3799 if (old_method->name() == new_method->name()) {
3800 if (old_method->signature() == new_method->signature()) {
3801 _matching_old_methods[_matching_methods_length ] = old_method;
3802 _matching_new_methods[_matching_methods_length++] = new_method;
3803 ++nj;
3804 ++oj;
3805 } else {
3806 // added overloaded have already been moved to the end,
3807 // so this is a deleted overloaded method
3808 _deleted_methods[_deleted_methods_length++] = old_method;
3809 ++oj;
3810 }
3811 } else { // names don't match
3812 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3813 // new method
3814 _added_methods[_added_methods_length++] = new_method;
3815 ++nj;
3816 } else {
3817 // deleted method
3818 _deleted_methods[_deleted_methods_length++] = old_method;
3819 ++oj;
3820 }
3821 }
3822 }
3823 }
3824 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3825 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3826 }
3827
3828
3829 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3830 instanceKlassHandle scratch_class) {
3831 // Swap annotation fields values
3832 Annotations* old_annotations = the_class->annotations();
3833 the_class->set_annotations(scratch_class->annotations());
3834 scratch_class->set_annotations(old_annotations);
3835 }
3836
3837
3838 // Install the redefinition of a class:
3839 // - house keeping (flushing breakpoints and caches, deoptimizing
3840 // dependent compiled code)
3841 // - replacing parts in the_class with parts from scratch_class
3842 // - adding a weak reference to track the obsolete but interesting
3843 // parts of the_class
3844 // - adjusting constant pool caches and vtables in other classes
3845 // that refer to methods in the_class. These adjustments use the
3846 // ClassLoaderDataGraph::classes_do() facility which only allows
3847 // a helper method to be specified. The interesting parameters
3848 // that we would like to pass to the helper method are saved in
3849 // static global fields in the VM operation.
3850 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3851 Klass* scratch_class_oop, TRAPS) {
3852
3853 HandleMark hm(THREAD); // make sure handles from this call are freed
3854 RC_TIMER_START(_timer_rsc_phase1);
3855
3856 instanceKlassHandle scratch_class(scratch_class_oop);
3857
3858 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3859 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3860 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3861
3862 // Remove all breakpoints in methods of this class
3863 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3864 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3865
3866 // Deoptimize all compiled code that depends on this class
3867 flush_dependent_code(the_class, THREAD);
3868
3869 _old_methods = the_class->methods();
3870 _new_methods = scratch_class->methods();
3871 _the_class_oop = the_class_oop;
3872 compute_added_deleted_matching_methods();
3873 update_jmethod_ids();
3874
3875 // Attach new constant pool to the original klass. The original
3876 // klass still refers to the old constant pool (for now).
3877 scratch_class->constants()->set_pool_holder(the_class());
3878
3879 #if 0
3880 // In theory, with constant pool merging in place we should be able
3881 // to save space by using the new, merged constant pool in place of
3882 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3883 // the klass version we are replacing now and any constant pool(s) in
3884 // previous versions of klass. Nice theory, doesn't work in practice.
3885 // When this code is enabled, even simple programs throw NullPointer
3886 // exceptions. I'm guessing that this is caused by some constant pool
3887 // cache difference between the new, merged constant pool and the
3888 // constant pool that was just being used by the klass. I'm keeping
3889 // this code around to archive the idea, but the code has to remain
3890 // disabled for now.
3891
3892 // Attach each old method to the new constant pool. This can be
3893 // done here since we are past the bytecode verification and
3894 // constant pool optimization phases.
3895 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3896 Method* method = _old_methods->at(i);
3897 method->set_constants(scratch_class->constants());
3898 }
3899
3900 {
3901 // walk all previous versions of the klass
3902 InstanceKlass *ik = (InstanceKlass *)the_class();
3903 PreviousVersionWalker pvw(ik);
3904 instanceKlassHandle ikh;
3905 do {
3906 ikh = pvw.next_previous_version();
3907 if (!ikh.is_null()) {
3908 ik = ikh();
3909
3910 // attach previous version of klass to the new constant pool
3911 ik->set_constants(scratch_class->constants());
3912
3913 // Attach each method in the previous version of klass to the
3914 // new constant pool
3915 Array<Method*>* prev_methods = ik->methods();
3916 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3917 Method* method = prev_methods->at(i);
3918 method->set_constants(scratch_class->constants());
3919 }
3920 }
3921 } while (!ikh.is_null());
3922 }
3923 #endif
3924
3925 // Replace methods and constantpool
3926 the_class->set_methods(_new_methods);
3927 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3928 // and to be able to undo operation easily.
3929
3930 ConstantPool* old_constants = the_class->constants();
3931 the_class->set_constants(scratch_class->constants());
3932 scratch_class->set_constants(old_constants); // See the previous comment.
3933 #if 0
3934 // We are swapping the guts of "the new class" with the guts of "the
3935 // class". Since the old constant pool has just been attached to "the
3936 // new class", it seems logical to set the pool holder in the old
3937 // constant pool also. However, doing this will change the observable
3938 // class hierarchy for any old methods that are still executing. A
3939 // method can query the identity of its "holder" and this query uses
3940 // the method's constant pool link to find the holder. The change in
3941 // holding class from "the class" to "the new class" can confuse
3942 // things.
3943 //
3944 // Setting the old constant pool's holder will also cause
3945 // verification done during vtable initialization below to fail.
3946 // During vtable initialization, the vtable's class is verified to be
3947 // a subtype of the method's holder. The vtable's class is "the
3948 // class" and the method's holder is gotten from the constant pool
3949 // link in the method itself. For "the class"'s directly implemented
3950 // methods, the method holder is "the class" itself (as gotten from
3951 // the new constant pool). The check works fine in this case. The
3952 // check also works fine for methods inherited from super classes.
3953 //
3954 // Miranda methods are a little more complicated. A miranda method is
3955 // provided by an interface when the class implementing the interface
3956 // does not provide its own method. These interfaces are implemented
3957 // internally as an InstanceKlass. These special instanceKlasses
3958 // share the constant pool of the class that "implements" the
3959 // interface. By sharing the constant pool, the method holder of a
3960 // miranda method is the class that "implements" the interface. In a
3961 // non-redefine situation, the subtype check works fine. However, if
3962 // the old constant pool's pool holder is modified, then the check
3963 // fails because there is no class hierarchy relationship between the
3964 // vtable's class and "the new class".
3965
3966 old_constants->set_pool_holder(scratch_class());
3967 #endif
3968
3969 // track which methods are EMCP for add_previous_version() call below
3970 BitMap emcp_methods(_old_methods->length());
3971 int emcp_method_count = 0;
3972 emcp_methods.clear(); // clears 0..(length() - 1)
3973 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3974 transfer_old_native_function_registrations(the_class);
3975
3976 // The class file bytes from before any retransformable agents mucked
3977 // with them was cached on the scratch class, move to the_class.
3978 // Note: we still want to do this if nothing needed caching since it
3979 // should get cleared in the_class too.
3980 if (the_class->get_cached_class_file_bytes() == 0) {
3981 // the_class doesn't have a cache yet so copy it
3982 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3983 }
3984 #ifndef PRODUCT
3985 else {
3986 assert(the_class->get_cached_class_file_bytes() ==
3987 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3988 assert(the_class->get_cached_class_file_len() ==
3989 scratch_class->get_cached_class_file_len(), "cache lens must match");
3990 }
3991 #endif
3992
3993 // NULL out in scratch class to not delete twice. The class to be redefined
3994 // always owns these bytes.
3995 scratch_class->set_cached_class_file(NULL);
3996
3997 // Replace inner_classes
3998 Array<u2>* old_inner_classes = the_class->inner_classes();
3999 the_class->set_inner_classes(scratch_class->inner_classes());
4000 scratch_class->set_inner_classes(old_inner_classes);
4001
4002 // Initialize the vtable and interface table after
4003 // methods have been rewritten
4004 {
4005 ResourceMark rm(THREAD);
4006 // no exception should happen here since we explicitly
4007 // do not check loader constraints.
4008 // compare_and_normalize_class_versions has already checked:
4009 // - classloaders unchanged, signatures unchanged
4010 // - all instanceKlasses for redefined classes reused & contents updated
4011 the_class->vtable()->initialize_vtable(false, THREAD);
4012 the_class->itable()->initialize_itable(false, THREAD);
4013 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4014 }
4015
4016 // Leave arrays of jmethodIDs and itable index cache unchanged
4017
4018 // Copy the "source file name" attribute from new class version
4019 the_class->set_source_file_name_index(
4020 scratch_class->source_file_name_index());
4021
4022 // Copy the "source debug extension" attribute from new class version
4023 the_class->set_source_debug_extension(
4024 scratch_class->source_debug_extension(),
4025 scratch_class->source_debug_extension() == NULL ? 0 :
4026 (int)strlen(scratch_class->source_debug_extension()));
4027
4028 // Use of javac -g could be different in the old and the new
4029 if (scratch_class->access_flags().has_localvariable_table() !=
4030 the_class->access_flags().has_localvariable_table()) {
4031
4032 AccessFlags flags = the_class->access_flags();
4033 if (scratch_class->access_flags().has_localvariable_table()) {
4034 flags.set_has_localvariable_table();
4035 } else {
4036 flags.clear_has_localvariable_table();
4037 }
4038 the_class->set_access_flags(flags);
4039 }
4040
4041 swap_annotations(the_class, scratch_class);
4042
4043 // Replace minor version number of class file
4044 u2 old_minor_version = the_class->minor_version();
4045 the_class->set_minor_version(scratch_class->minor_version());
4046 scratch_class->set_minor_version(old_minor_version);
4047
4048 // Replace major version number of class file
4049 u2 old_major_version = the_class->major_version();
4050 the_class->set_major_version(scratch_class->major_version());
4051 scratch_class->set_major_version(old_major_version);
4052
4053 // Replace CP indexes for class and name+type of enclosing method
4054 u2 old_class_idx = the_class->enclosing_method_class_index();
4055 u2 old_method_idx = the_class->enclosing_method_method_index();
4056 the_class->set_enclosing_method_indices(
4057 scratch_class->enclosing_method_class_index(),
4058 scratch_class->enclosing_method_method_index());
4059 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4060
4061 // keep track of previous versions of this class
4062 the_class->add_previous_version(scratch_class, &emcp_methods,
4063 emcp_method_count);
4064
4065 RC_TIMER_STOP(_timer_rsc_phase1);
4066 RC_TIMER_START(_timer_rsc_phase2);
4067
4068 // Adjust constantpool caches and vtables for all classes
4069 // that reference methods of the evolved class.
4070 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4071 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4072
4073 // JSR-292 support
4074 MemberNameTable* mnt = the_class->member_names();
4075 if (mnt != NULL) {
4076 bool trace_name_printed = false;
4077 mnt->adjust_method_entries(_matching_old_methods,
4078 _matching_new_methods,
4079 _matching_methods_length,
4080 &trace_name_printed);
4081 }
4082
4083 // Fix Resolution Error table also to remove old constant pools
4084 SystemDictionary::delete_resolution_error(old_constants);
4085
4086 if (the_class->oop_map_cache() != NULL) {
4087 // Flush references to any obsolete methods from the oop map cache
4088 // so that obsolete methods are not pinned.
4089 the_class->oop_map_cache()->flush_obsolete_entries();
4090 }
4091
4092 // increment the classRedefinedCount field in the_class and in any
4093 // direct and indirect subclasses of the_class
4094 increment_class_counter((InstanceKlass *)the_class(), THREAD);
4095
4096 // RC_TRACE macro has an embedded ResourceMark
4097 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
4098 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4099 the_class->external_name(),
4100 java_lang_Class::classRedefinedCount(the_class_mirror),
4101 os::available_memory() >> 10));
4102
4103 RC_TIMER_STOP(_timer_rsc_phase2);
4104 } // end redefine_single_class()
4105
4106
4107 // Increment the classRedefinedCount field in the specific InstanceKlass
4108 // and in all direct and indirect subclasses.
4109 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4110 oop class_mirror = ik->java_mirror();
4111 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4112 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4113 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4114
4115 if (class_oop != _the_class_oop) {
4116 // _the_class_oop count is printed at end of redefine_single_class()
4117 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
4118 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
4119 }
4120
4121 for (Klass *subk = ik->subklass(); subk != NULL;
4122 subk = subk->next_sibling()) {
4123 if (subk->oop_is_instance()) {
4124 // Only update instanceKlasses
4125 InstanceKlass *subik = (InstanceKlass*)subk;
4126 // recursively do subclasses of the current subclass
4127 increment_class_counter(subik, THREAD);
4128 }
4129 }
4130 }
4131
4132 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4133 bool no_old_methods = true; // be optimistic
4134
4135 // Both array and instance classes have vtables.
4136 // a vtable should never contain old or obsolete methods
4137 ResourceMark rm(_thread);
4138 if (k->vtable_length() > 0 &&
4139 !k->vtable()->check_no_old_or_obsolete_entries()) {
4140 if (RC_TRACE_ENABLED(0x00004000)) {
4141 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4142 ("klassVtable::check_no_old_or_obsolete_entries failure"
4143 " -- OLD or OBSOLETE method found -- class: %s",
4144 k->signature_name()));
4145 k->vtable()->dump_vtable();
4146 }
4147 no_old_methods = false;
4148 }
4149
4150 if (k->oop_is_instance()) {
4151 HandleMark hm(_thread);
4152 InstanceKlass *ik = InstanceKlass::cast(k);
4153
4154 // an itable should never contain old or obsolete methods
4155 if (ik->itable_length() > 0 &&
4156 !ik->itable()->check_no_old_or_obsolete_entries()) {
4157 if (RC_TRACE_ENABLED(0x00004000)) {
4158 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4159 ("klassItable::check_no_old_or_obsolete_entries failure"
4160 " -- OLD or OBSOLETE method found -- class: %s",
4161 ik->signature_name()));
4162 ik->itable()->dump_itable();
4163 }
4164 no_old_methods = false;
4165 }
4166
4167 // the constant pool cache should never contain old or obsolete methods
4168 if (ik->constants() != NULL &&
4169 ik->constants()->cache() != NULL &&
4170 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4171 if (RC_TRACE_ENABLED(0x00004000)) {
4172 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4173 ("cp-cache::check_no_old_or_obsolete_entries failure"
4174 " -- OLD or OBSOLETE method found -- class: %s",
4175 ik->signature_name()));
4176 ik->constants()->cache()->dump_cache();
4177 }
4178 no_old_methods = false;
4179 }
4180 }
4181
4182 // print and fail guarantee if old methods are found.
4183 if (!no_old_methods) {
4184 if (RC_TRACE_ENABLED(0x00004000)) {
4185 dump_methods();
4186 } else {
4187 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
4188 "to see more info about the following guarantee() failure.");
4189 }
4190 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4191 }
4192 }
4193
4194
4195 void VM_RedefineClasses::dump_methods() {
4196 int j;
4197 RC_TRACE(0x00004000, ("_old_methods --"));
4198 for (j = 0; j < _old_methods->length(); ++j) {
4199 Method* m = _old_methods->at(j);
4200 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4201 m->access_flags().print_on(tty);
4202 tty->print(" -- ");
4203 m->print_name(tty);
4204 tty->cr();
4205 }
4206 RC_TRACE(0x00004000, ("_new_methods --"));
4207 for (j = 0; j < _new_methods->length(); ++j) {
4208 Method* m = _new_methods->at(j);
4209 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4210 m->access_flags().print_on(tty);
4211 tty->print(" -- ");
4212 m->print_name(tty);
4213 tty->cr();
4214 }
4215 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
4216 for (j = 0; j < _matching_methods_length; ++j) {
4217 Method* m = _matching_old_methods[j];
4218 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4219 m->access_flags().print_on(tty);
4220 tty->print(" -- ");
4221 m->print_name(tty);
4222 tty->cr();
4223 m = _matching_new_methods[j];
4224 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
4225 m->access_flags().print_on(tty);
4226 tty->cr();
4227 }
4228 RC_TRACE(0x00004000, ("_deleted_methods --"));
4229 for (j = 0; j < _deleted_methods_length; ++j) {
4230 Method* m = _deleted_methods[j];
4231 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4232 m->access_flags().print_on(tty);
4233 tty->print(" -- ");
4234 m->print_name(tty);
4235 tty->cr();
4236 }
4237 RC_TRACE(0x00004000, ("_added_methods --"));
4238 for (j = 0; j < _added_methods_length; ++j) {
4239 Method* m = _added_methods[j];
4240 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4241 m->access_flags().print_on(tty);
4242 tty->print(" -- ");
4243 m->print_name(tty);
4244 tty->cr();
4245 }
4246 }