1 /*
2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/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 #include "utilities/events.hpp"
46
47 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
48
49 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
50 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
51 Method** VM_RedefineClasses::_matching_old_methods = NULL;
52 Method** VM_RedefineClasses::_matching_new_methods = NULL;
53 Method** VM_RedefineClasses::_deleted_methods = NULL;
54 Method** VM_RedefineClasses::_added_methods = NULL;
55 int VM_RedefineClasses::_matching_methods_length = 0;
56 int VM_RedefineClasses::_deleted_methods_length = 0;
57 int VM_RedefineClasses::_added_methods_length = 0;
58 Klass* VM_RedefineClasses::_the_class_oop = NULL;
59
60
61 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
62 const jvmtiClassDefinition *class_defs,
63 JvmtiClassLoadKind class_load_kind) {
64 _class_count = class_count;
65 _class_defs = class_defs;
66 _class_load_kind = class_load_kind;
67 _res = JVMTI_ERROR_NONE;
68 }
69
70 bool VM_RedefineClasses::doit_prologue() {
71 if (_class_count == 0) {
72 _res = JVMTI_ERROR_NONE;
73 return false;
74 }
75 if (_class_defs == NULL) {
76 _res = JVMTI_ERROR_NULL_POINTER;
77 return false;
78 }
79 for (int i = 0; i < _class_count; i++) {
80 if (_class_defs[i].klass == NULL) {
81 _res = JVMTI_ERROR_INVALID_CLASS;
82 return false;
83 }
84 if (_class_defs[i].class_byte_count == 0) {
85 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
86 return false;
87 }
88 if (_class_defs[i].class_bytes == NULL) {
89 _res = JVMTI_ERROR_NULL_POINTER;
90 return false;
91 }
92 }
93
94 // Start timer after all the sanity checks; not quite accurate, but
95 // better than adding a bunch of stop() calls.
96 RC_TIMER_START(_timer_vm_op_prologue);
97
98 // We first load new class versions in the prologue, because somewhere down the
99 // call chain it is required that the current thread is a Java thread.
100 _res = load_new_class_versions(Thread::current());
101 if (_res != JVMTI_ERROR_NONE) {
102 // free any successfully created classes, since none are redefined
103 for (int i = 0; i < _class_count; i++) {
104 if (_scratch_classes[i] != NULL) {
105 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
106 // Free the memory for this class at class unloading time. Not before
107 // because CMS might think this is still live.
108 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
109 }
110 }
111 // Free os::malloc allocated memory in load_new_class_version.
112 os::free(_scratch_classes);
113 RC_TIMER_STOP(_timer_vm_op_prologue);
114 return false;
115 }
116
117 RC_TIMER_STOP(_timer_vm_op_prologue);
118 return true;
119 }
120
121 void VM_RedefineClasses::doit() {
122 Thread *thread = Thread::current();
123
124 if (UseSharedSpaces) {
125 // Sharing is enabled so we remap the shared readonly space to
126 // shared readwrite, private just in case we need to redefine
127 // a shared class. We do the remap during the doit() phase of
128 // the safepoint to be safer.
129 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
130 RC_TRACE_WITH_THREAD(0x00000001, thread,
131 ("failed to remap shared readonly space to readwrite, private"));
132 _res = JVMTI_ERROR_INTERNAL;
133 return;
134 }
135 }
136
137 // Mark methods seen on stack and everywhere else so old methods are not
138 // cleaned up if they're on the stack.
139 MetadataOnStackMark md_on_stack(true);
140 HandleMark hm(thread); // make sure any handles created are deleted
141 // before the stack walk again.
142
143 for (int i = 0; i < _class_count; i++) {
144 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
145 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
146 // Free the memory for this class at class unloading time. Not before
147 // because CMS might think this is still live.
148 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
149 _scratch_classes[i] = NULL;
150 }
151
152 // Disable any dependent concurrent compilations
153 SystemDictionary::notice_modification();
154
155 // Set flag indicating that some invariants are no longer true.
156 // See jvmtiExport.hpp for detailed explanation.
157 JvmtiExport::set_has_redefined_a_class();
158
159 // check_class() is optionally called for product bits, but is
160 // always called for non-product bits.
161 #ifdef PRODUCT
162 if (RC_TRACE_ENABLED(0x00004000)) {
163 #endif
164 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
165 CheckClass check_class(thread);
166 ClassLoaderDataGraph::classes_do(&check_class);
167 #ifdef PRODUCT
168 }
169 #endif
170 }
171
172 void VM_RedefineClasses::doit_epilogue() {
173 // Free os::malloc allocated memory.
174 os::free(_scratch_classes);
175
176 // Reset the_class_oop to null for error printing.
177 _the_class_oop = NULL;
178
179 if (RC_TRACE_ENABLED(0x00000004)) {
180 // Used to have separate timers for "doit" and "all", but the timer
181 // overhead skewed the measurements.
182 jlong doit_time = _timer_rsc_phase1.milliseconds() +
183 _timer_rsc_phase2.milliseconds();
184 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
185
186 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
187 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
188 _timer_vm_op_prologue.milliseconds(), doit_time));
189 RC_TRACE(0x00000004,
190 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
191 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
192 }
193 }
194
195 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
196 // classes for primitives cannot be redefined
197 if (java_lang_Class::is_primitive(klass_mirror)) {
198 return false;
199 }
200 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
201 // classes for arrays cannot be redefined
202 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
203 return false;
204 }
205 return true;
206 }
207
208 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
209 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
210 // direct CP entries, there is just the current entry to append. For
211 // indirect and double-indirect CP entries, there are zero or more
212 // referenced CP entries along with the current entry to append.
213 // Indirect and double-indirect CP entries are handled by recursive
214 // calls to append_entry() as needed. The referenced CP entries are
215 // always appended to *merge_cp_p before the referee CP entry. These
216 // referenced CP entries may already exist in *merge_cp_p in which case
217 // there is nothing extra to append and only the current entry is
218 // appended.
219 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
220 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
221 TRAPS) {
222
223 // append is different depending on entry tag type
224 switch (scratch_cp->tag_at(scratch_i).value()) {
225
226 // The old verifier is implemented outside the VM. It loads classes,
227 // but does not resolve constant pool entries directly so we never
228 // see Class entries here with the old verifier. Similarly the old
229 // verifier does not like Class entries in the input constant pool.
230 // The split-verifier is implemented in the VM so it can optionally
231 // and directly resolve constant pool entries to load classes. The
232 // split-verifier can accept either Class entries or UnresolvedClass
233 // entries in the input constant pool. We revert the appended copy
234 // back to UnresolvedClass so that either verifier will be happy
235 // with the constant pool entry.
236 case JVM_CONSTANT_Class:
237 {
238 // revert the copy to JVM_CONSTANT_UnresolvedClass
239 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
240 scratch_cp->klass_name_at(scratch_i));
241
242 if (scratch_i != *merge_cp_length_p) {
243 // The new entry in *merge_cp_p is at a different index than
244 // the new entry in scratch_cp so we need to map the index values.
245 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
246 }
247 (*merge_cp_length_p)++;
248 } break;
249
250 // these are direct CP entries so they can be directly appended,
251 // but double and long take two constant pool entries
252 case JVM_CONSTANT_Double: // fall through
253 case JVM_CONSTANT_Long:
254 {
255 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
256 THREAD);
257
258 if (scratch_i != *merge_cp_length_p) {
259 // The new entry in *merge_cp_p is at a different index than
260 // the new entry in scratch_cp so we need to map the index values.
261 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
262 }
263 (*merge_cp_length_p) += 2;
264 } break;
265
266 // these are direct CP entries so they can be directly appended
267 case JVM_CONSTANT_Float: // fall through
268 case JVM_CONSTANT_Integer: // fall through
269 case JVM_CONSTANT_Utf8: // fall through
270
271 // This was an indirect CP entry, but it has been changed into
272 // Symbol*s so this entry can be directly appended.
273 case JVM_CONSTANT_String: // fall through
274
275 // These were indirect CP entries, but they have been changed into
276 // Symbol*s so these entries can be directly appended.
277 case JVM_CONSTANT_UnresolvedClass: // fall through
278 {
279 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
280 THREAD);
281
282 if (scratch_i != *merge_cp_length_p) {
283 // The new entry in *merge_cp_p is at a different index than
284 // the new entry in scratch_cp so we need to map the index values.
285 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
286 }
287 (*merge_cp_length_p)++;
288 } break;
289
290 // this is an indirect CP entry so it needs special handling
291 case JVM_CONSTANT_NameAndType:
292 {
293 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
294 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
295 merge_cp_length_p, THREAD);
296
297 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
298 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
299 merge_cp_p, merge_cp_length_p,
300 THREAD);
301
302 // If the referenced entries already exist in *merge_cp_p, then
303 // both new_name_ref_i and new_signature_ref_i will both be 0.
304 // In that case, all we are appending is the current entry.
305 if (new_name_ref_i != name_ref_i) {
306 RC_TRACE(0x00080000,
307 ("NameAndType entry@%d name_ref_index change: %d to %d",
308 *merge_cp_length_p, name_ref_i, new_name_ref_i));
309 }
310 if (new_signature_ref_i != signature_ref_i) {
311 RC_TRACE(0x00080000,
312 ("NameAndType entry@%d signature_ref_index change: %d to %d",
313 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
314 }
315
316 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
317 new_name_ref_i, new_signature_ref_i);
318 if (scratch_i != *merge_cp_length_p) {
319 // The new entry in *merge_cp_p is at a different index than
320 // the new entry in scratch_cp so we need to map the index values.
321 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
322 }
323 (*merge_cp_length_p)++;
324 } break;
325
326 // this is a double-indirect CP entry so it needs special handling
327 case JVM_CONSTANT_Fieldref: // fall through
328 case JVM_CONSTANT_InterfaceMethodref: // fall through
329 case JVM_CONSTANT_Methodref:
330 {
331 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
332 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
333 merge_cp_p, merge_cp_length_p, THREAD);
334
335 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
336 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
337 merge_cp_p, merge_cp_length_p, THREAD);
338
339 const char *entry_name = NULL;
340 switch (scratch_cp->tag_at(scratch_i).value()) {
341 case JVM_CONSTANT_Fieldref:
342 entry_name = "Fieldref";
343 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
344 new_name_and_type_ref_i);
345 break;
346 case JVM_CONSTANT_InterfaceMethodref:
347 entry_name = "IFMethodref";
348 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
349 new_klass_ref_i, new_name_and_type_ref_i);
350 break;
351 case JVM_CONSTANT_Methodref:
352 entry_name = "Methodref";
353 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
354 new_name_and_type_ref_i);
355 break;
356 default:
357 guarantee(false, "bad switch");
358 break;
359 }
360
361 if (klass_ref_i != new_klass_ref_i) {
362 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
363 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
364 }
365 if (name_and_type_ref_i != new_name_and_type_ref_i) {
366 RC_TRACE(0x00080000,
367 ("%s entry@%d name_and_type_index changed: %d to %d",
368 entry_name, *merge_cp_length_p, name_and_type_ref_i,
369 new_name_and_type_ref_i));
370 }
371
372 if (scratch_i != *merge_cp_length_p) {
373 // The new entry in *merge_cp_p is at a different index than
374 // the new entry in scratch_cp so we need to map the index values.
375 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
376 }
377 (*merge_cp_length_p)++;
378 } break;
379
380 // this is an indirect CP entry so it needs special handling
381 case JVM_CONSTANT_MethodType:
382 {
383 int ref_i = scratch_cp->method_type_index_at(scratch_i);
384 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
385 merge_cp_length_p, THREAD);
386 if (new_ref_i != ref_i) {
387 RC_TRACE(0x00080000,
388 ("MethodType entry@%d ref_index change: %d to %d",
389 *merge_cp_length_p, ref_i, new_ref_i));
390 }
391 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
392 if (scratch_i != *merge_cp_length_p) {
393 // The new entry in *merge_cp_p is at a different index than
394 // the new entry in scratch_cp so we need to map the index values.
395 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
396 }
397 (*merge_cp_length_p)++;
398 } break;
399
400 // this is an indirect CP entry so it needs special handling
401 case JVM_CONSTANT_MethodHandle:
402 {
403 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
404 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
405 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
406 merge_cp_length_p, THREAD);
407 if (new_ref_i != ref_i) {
408 RC_TRACE(0x00080000,
409 ("MethodHandle entry@%d ref_index change: %d to %d",
410 *merge_cp_length_p, ref_i, new_ref_i));
411 }
412 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
413 if (scratch_i != *merge_cp_length_p) {
414 // The new entry in *merge_cp_p is at a different index than
415 // the new entry in scratch_cp so we need to map the index values.
416 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
417 }
418 (*merge_cp_length_p)++;
419 } break;
420
421 // this is an indirect CP entry so it needs special handling
422 case JVM_CONSTANT_InvokeDynamic:
423 {
424 // Index of the bootstrap specifier in the operands array
425 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
426 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
427 merge_cp_length_p, THREAD);
428 // The bootstrap method NameAndType_info index
429 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
430 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
431 merge_cp_length_p, THREAD);
432 if (new_bs_i != old_bs_i) {
433 RC_TRACE(0x00080000,
434 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
435 *merge_cp_length_p, old_bs_i, new_bs_i));
436 }
437 if (new_ref_i != old_ref_i) {
438 RC_TRACE(0x00080000,
439 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
440 *merge_cp_length_p, old_ref_i, new_ref_i));
441 }
442
443 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
444 if (scratch_i != *merge_cp_length_p) {
445 // The new entry in *merge_cp_p is at a different index than
446 // the new entry in scratch_cp so we need to map the index values.
447 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
448 }
449 (*merge_cp_length_p)++;
450 } break;
451
452 // At this stage, Class or UnresolvedClass could be here, but not
453 // ClassIndex
454 case JVM_CONSTANT_ClassIndex: // fall through
455
456 // Invalid is used as the tag for the second constant pool entry
457 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
458 // not be seen by itself.
459 case JVM_CONSTANT_Invalid: // fall through
460
461 // At this stage, String could be here, but not StringIndex
462 case JVM_CONSTANT_StringIndex: // fall through
463
464 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
465 // here
466 case JVM_CONSTANT_UnresolvedClassInError: // fall through
467
468 default:
469 {
470 // leave a breadcrumb
471 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
472 ShouldNotReachHere();
473 } break;
474 } // end switch tag value
475 } // end append_entry()
476
477
478 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
479 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
480
481 int new_ref_i = ref_i;
482 bool match = (ref_i < *merge_cp_length_p) &&
483 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
484
485 if (!match) {
486 // forward reference in *merge_cp_p or not a direct match
487 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
488 if (found_i != 0) {
489 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
490 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
491 new_ref_i = found_i;
492 map_index(scratch_cp, ref_i, found_i);
493 } else {
494 // no match found so we have to append this entry to *merge_cp_p
495 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
496 // The above call to append_entry() can only append one entry
497 // so the post call query of *merge_cp_length_p is only for
498 // the sake of consistency.
499 new_ref_i = *merge_cp_length_p - 1;
500 }
501 }
502
503 return new_ref_i;
504 } // end find_or_append_indirect_entry()
505
506
507 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
508 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
509 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
510 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
511 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
512
513 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
514 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
515 merge_cp_length_p, THREAD);
516 if (new_ref_i != old_ref_i) {
517 RC_TRACE(0x00080000,
518 ("operands entry@%d bootstrap method ref_index change: %d to %d",
519 _operands_cur_length, old_ref_i, new_ref_i));
520 }
521
522 Array<u2>* merge_ops = (*merge_cp_p)->operands();
523 int new_bs_i = _operands_cur_length;
524 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
525 // However, the operand_offset_at(0) was set in the extend_operands() call.
526 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
527 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
528 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
529
530 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
531 merge_ops->at_put(new_base++, new_ref_i);
532 merge_ops->at_put(new_base++, argc);
533
534 for (int i = 0; i < argc; i++) {
535 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
536 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
537 merge_cp_length_p, THREAD);
538 merge_ops->at_put(new_base++, new_arg_ref_i);
539 if (new_arg_ref_i != old_arg_ref_i) {
540 RC_TRACE(0x00080000,
541 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
542 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
543 }
544 }
545 if (old_bs_i != _operands_cur_length) {
546 // The bootstrap specifier in *merge_cp_p is at a different index than
547 // that in scratch_cp so we need to map the index values.
548 map_operand_index(old_bs_i, new_bs_i);
549 }
550 _operands_cur_length++;
551 } // end append_operand()
552
553
554 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
555 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
556
557 int new_bs_i = old_bs_i; // bootstrap specifier index
558 bool match = (old_bs_i < _operands_cur_length) &&
559 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
560
561 if (!match) {
562 // forward reference in *merge_cp_p or not a direct match
563 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
564 _operands_cur_length, THREAD);
565 if (found_i != -1) {
566 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
567 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
568 new_bs_i = found_i;
569 map_operand_index(old_bs_i, found_i);
570 } else {
571 // no match found so we have to append this bootstrap specifier to *merge_cp_p
572 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
573 new_bs_i = _operands_cur_length - 1;
574 }
575 }
576 return new_bs_i;
577 } // end find_or_append_operand()
578
579
580 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
581 if (merge_cp->operands() == NULL) {
582 return;
583 }
584 // Shrink the merge_cp operands
585 merge_cp->shrink_operands(_operands_cur_length, CHECK);
586
587 if (RC_TRACE_ENABLED(0x00040000)) {
588 // don't want to loop unless we are tracing
589 int count = 0;
590 for (int i = 1; i < _operands_index_map_p->length(); i++) {
591 int value = _operands_index_map_p->at(i);
592 if (value != -1) {
593 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
594 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
595 count++;
596 }
597 }
598 }
599 // Clean-up
600 _operands_index_map_p = NULL;
601 _operands_cur_length = 0;
602 _operands_index_map_count = 0;
603 } // end finalize_operands_merge()
604
605
606 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
607 instanceKlassHandle the_class,
608 instanceKlassHandle scratch_class) {
609 int i;
610
611 // Check superclasses, or rather their names, since superclasses themselves can be
612 // requested to replace.
613 // Check for NULL superclass first since this might be java.lang.Object
614 if (the_class->super() != scratch_class->super() &&
615 (the_class->super() == NULL || scratch_class->super() == NULL ||
616 the_class->super()->name() !=
617 scratch_class->super()->name())) {
618 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
619 }
620
621 // Check if the number, names and order of directly implemented interfaces are the same.
622 // I think in principle we should just check if the sets of names of directly implemented
623 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
624 // .java file, also changes in .class file) should not matter. However, comparing sets is
625 // technically a bit more difficult, and, more importantly, I am not sure at present that the
626 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
627 // rely on it somewhere.
628 Array<Klass*>* k_interfaces = the_class->local_interfaces();
629 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
630 int n_intfs = k_interfaces->length();
631 if (n_intfs != k_new_interfaces->length()) {
632 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
633 }
634 for (i = 0; i < n_intfs; i++) {
635 if (k_interfaces->at(i)->name() !=
636 k_new_interfaces->at(i)->name()) {
637 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
638 }
639 }
640
641 // Check whether class is in the error init state.
642 if (the_class->is_in_error_state()) {
643 // TBD #5057930: special error code is needed in 1.6
644 return JVMTI_ERROR_INVALID_CLASS;
645 }
646
647 // Check whether class modifiers are the same.
648 jushort old_flags = (jushort) the_class->access_flags().get_flags();
649 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
650 if (old_flags != new_flags) {
651 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
652 }
653
654 // Check if the number, names, types and order of fields declared in these classes
655 // are the same.
656 JavaFieldStream old_fs(the_class);
657 JavaFieldStream new_fs(scratch_class);
658 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
659 // access
660 old_flags = old_fs.access_flags().as_short();
661 new_flags = new_fs.access_flags().as_short();
662 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
663 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
664 }
665 // offset
666 if (old_fs.offset() != new_fs.offset()) {
667 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
668 }
669 // name and signature
670 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
671 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
672 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
673 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
674 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
675 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
676 }
677 }
678
679 // If both streams aren't done then we have a differing number of
680 // fields.
681 if (!old_fs.done() || !new_fs.done()) {
682 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
683 }
684
685 // Do a parallel walk through the old and new methods. Detect
686 // cases where they match (exist in both), have been added in
687 // the new methods, or have been deleted (exist only in the
688 // old methods). The class file parser places methods in order
689 // by method name, but does not order overloaded methods by
690 // signature. In order to determine what fate befell the methods,
691 // this code places the overloaded new methods that have matching
692 // old methods in the same order as the old methods and places
693 // new overloaded methods at the end of overloaded methods of
694 // that name. The code for this order normalization is adapted
695 // from the algorithm used in InstanceKlass::find_method().
696 // Since we are swapping out of order entries as we find them,
697 // we only have to search forward through the overloaded methods.
698 // Methods which are added and have the same name as an existing
699 // method (but different signature) will be put at the end of
700 // the methods with that name, and the name mismatch code will
701 // handle them.
702 Array<Method*>* k_old_methods(the_class->methods());
703 Array<Method*>* k_new_methods(scratch_class->methods());
704 int n_old_methods = k_old_methods->length();
705 int n_new_methods = k_new_methods->length();
706 Thread* thread = Thread::current();
707
708 int ni = 0;
709 int oi = 0;
710 while (true) {
711 Method* k_old_method;
712 Method* k_new_method;
713 enum { matched, added, deleted, undetermined } method_was = undetermined;
714
715 if (oi >= n_old_methods) {
716 if (ni >= n_new_methods) {
717 break; // we've looked at everything, done
718 }
719 // New method at the end
720 k_new_method = k_new_methods->at(ni);
721 method_was = added;
722 } else if (ni >= n_new_methods) {
723 // Old method, at the end, is deleted
724 k_old_method = k_old_methods->at(oi);
725 method_was = deleted;
726 } else {
727 // There are more methods in both the old and new lists
728 k_old_method = k_old_methods->at(oi);
729 k_new_method = k_new_methods->at(ni);
730 if (k_old_method->name() != k_new_method->name()) {
731 // Methods are sorted by method name, so a mismatch means added
732 // or deleted
733 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
734 method_was = added;
735 } else {
736 method_was = deleted;
737 }
738 } else if (k_old_method->signature() == k_new_method->signature()) {
739 // Both the name and signature match
740 method_was = matched;
741 } else {
742 // The name matches, but the signature doesn't, which means we have to
743 // search forward through the new overloaded methods.
744 int nj; // outside the loop for post-loop check
745 for (nj = ni + 1; nj < n_new_methods; nj++) {
746 Method* m = k_new_methods->at(nj);
747 if (k_old_method->name() != m->name()) {
748 // reached another method name so no more overloaded methods
749 method_was = deleted;
750 break;
751 }
752 if (k_old_method->signature() == m->signature()) {
753 // found a match so swap the methods
754 k_new_methods->at_put(ni, m);
755 k_new_methods->at_put(nj, k_new_method);
756 k_new_method = m;
757 method_was = matched;
758 break;
759 }
760 }
761
762 if (nj >= n_new_methods) {
763 // reached the end without a match; so method was deleted
764 method_was = deleted;
765 }
766 }
767 }
768
769 switch (method_was) {
770 case matched:
771 // methods match, be sure modifiers do too
772 old_flags = (jushort) k_old_method->access_flags().get_flags();
773 new_flags = (jushort) k_new_method->access_flags().get_flags();
774 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
775 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
776 }
777 {
778 u2 new_num = k_new_method->method_idnum();
779 u2 old_num = k_old_method->method_idnum();
780 if (new_num != old_num) {
781 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
782 if (idnum_owner != NULL) {
783 // There is already a method assigned this idnum -- switch them
784 // Take current and original idnum from the new_method
785 idnum_owner->set_method_idnum(new_num);
786 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
787 }
788 // Take current and original idnum from the old_method
789 k_new_method->set_method_idnum(old_num);
790 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
791 if (thread->has_pending_exception()) {
792 return JVMTI_ERROR_OUT_OF_MEMORY;
793 }
794 }
795 }
796 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
797 k_new_method->name_and_sig_as_C_string(), ni,
798 k_old_method->name_and_sig_as_C_string(), oi));
799 // advance to next pair of methods
800 ++oi;
801 ++ni;
802 break;
803 case added:
804 // method added, see if it is OK
805 new_flags = (jushort) k_new_method->access_flags().get_flags();
806 if ((new_flags & JVM_ACC_PRIVATE) == 0
807 // hack: private should be treated as final, but alas
808 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
809 ) {
810 // new methods must be private
811 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
812 }
813 {
814 u2 num = the_class->next_method_idnum();
815 if (num == ConstMethod::UNSET_IDNUM) {
816 // cannot add any more methods
817 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
818 }
819 u2 new_num = k_new_method->method_idnum();
820 Method* idnum_owner = scratch_class->method_with_idnum(num);
821 if (idnum_owner != NULL) {
822 // There is already a method assigned this idnum -- switch them
823 // Take current and original idnum from the new_method
824 idnum_owner->set_method_idnum(new_num);
825 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
826 }
827 k_new_method->set_method_idnum(num);
828 k_new_method->set_orig_method_idnum(num);
829 if (thread->has_pending_exception()) {
830 return JVMTI_ERROR_OUT_OF_MEMORY;
831 }
832 }
833 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
834 k_new_method->name_and_sig_as_C_string(), ni));
835 ++ni; // advance to next new method
836 break;
837 case deleted:
838 // method deleted, see if it is OK
839 old_flags = (jushort) k_old_method->access_flags().get_flags();
840 if ((old_flags & JVM_ACC_PRIVATE) == 0
841 // hack: private should be treated as final, but alas
842 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
843 ) {
844 // deleted methods must be private
845 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
846 }
847 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
848 k_old_method->name_and_sig_as_C_string(), oi));
849 ++oi; // advance to next old method
850 break;
851 default:
852 ShouldNotReachHere();
853 }
854 }
855
856 return JVMTI_ERROR_NONE;
857 }
858
859
860 // Find new constant pool index value for old constant pool index value
861 // by seaching the index map. Returns zero (0) if there is no mapped
862 // value for the old constant pool index.
863 int VM_RedefineClasses::find_new_index(int old_index) {
864 if (_index_map_count == 0) {
865 // map is empty so nothing can be found
866 return 0;
867 }
868
869 if (old_index < 1 || old_index >= _index_map_p->length()) {
870 // The old_index is out of range so it is not mapped. This should
871 // not happen in regular constant pool merging use, but it can
872 // happen if a corrupt annotation is processed.
873 return 0;
874 }
875
876 int value = _index_map_p->at(old_index);
877 if (value == -1) {
878 // the old_index is not mapped
879 return 0;
880 }
881
882 return value;
883 } // end find_new_index()
884
885
886 // Find new bootstrap specifier index value for old bootstrap specifier index
887 // value by seaching the index map. Returns unused index (-1) if there is
888 // no mapped value for the old bootstrap specifier index.
889 int VM_RedefineClasses::find_new_operand_index(int old_index) {
890 if (_operands_index_map_count == 0) {
891 // map is empty so nothing can be found
892 return -1;
893 }
894
895 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
896 // The old_index is out of range so it is not mapped.
897 // This should not happen in regular constant pool merging use.
898 return -1;
899 }
900
901 int value = _operands_index_map_p->at(old_index);
902 if (value == -1) {
903 // the old_index is not mapped
904 return -1;
905 }
906
907 return value;
908 } // end find_new_operand_index()
909
910
911 // Returns true if the current mismatch is due to a resolved/unresolved
912 // class pair. Otherwise, returns false.
913 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
914 int index1, constantPoolHandle cp2, int index2) {
915
916 jbyte t1 = cp1->tag_at(index1).value();
917 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
918 return false; // wrong entry type; not our special case
919 }
920
921 jbyte t2 = cp2->tag_at(index2).value();
922 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
923 return false; // wrong entry type; not our special case
924 }
925
926 if (t1 == t2) {
927 return false; // not a mismatch; not our special case
928 }
929
930 char *s1 = cp1->klass_name_at(index1)->as_C_string();
931 char *s2 = cp2->klass_name_at(index2)->as_C_string();
932 if (strcmp(s1, s2) != 0) {
933 return false; // strings don't match; not our special case
934 }
935
936 return true; // made it through the gauntlet; this is our special case
937 } // end is_unresolved_class_mismatch()
938
939
940 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
941
942 // For consistency allocate memory using os::malloc wrapper.
943 _scratch_classes = (Klass**)
944 os::malloc(sizeof(Klass*) * _class_count, mtClass);
945 if (_scratch_classes == NULL) {
946 return JVMTI_ERROR_OUT_OF_MEMORY;
947 }
948 // Zero initialize the _scratch_classes array.
949 for (int i = 0; i < _class_count; i++) {
950 _scratch_classes[i] = NULL;
951 }
952
953 ResourceMark rm(THREAD);
954
955 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
956 // state can only be NULL if the current thread is exiting which
957 // should not happen since we're trying to do a RedefineClasses
958 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
959 for (int i = 0; i < _class_count; i++) {
960 // Create HandleMark so that any handles created while loading new class
961 // versions are deleted. Constant pools are deallocated while merging
962 // constant pools
963 HandleMark hm(THREAD);
964
965 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
966 // classes for primitives cannot be redefined
967 if (!is_modifiable_class(mirror)) {
968 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
969 }
970 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
971 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
972 Symbol* the_class_sym = the_class->name();
973
974 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
975 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
976 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
977 the_class->external_name(), _class_load_kind,
978 os::available_memory() >> 10));
979
980 ClassFileStream st((u1*) _class_defs[i].class_bytes,
981 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
982
983 // Parse the stream.
984 Handle the_class_loader(THREAD, the_class->class_loader());
985 Handle protection_domain(THREAD, the_class->protection_domain());
986 // Set redefined class handle in JvmtiThreadState class.
987 // This redefined class is sent to agent event handler for class file
988 // load hook event.
989 state->set_class_being_redefined(&the_class, _class_load_kind);
990
991 Klass* k = SystemDictionary::parse_stream(the_class_sym,
992 the_class_loader,
993 protection_domain,
994 &st,
995 THREAD);
996 // Clear class_being_redefined just to be sure.
997 state->clear_class_being_redefined();
998
999 // TODO: if this is retransform, and nothing changed we can skip it
1000
1001 instanceKlassHandle scratch_class (THREAD, k);
1002
1003 // Need to clean up allocated InstanceKlass if there's an error so assign
1004 // the result here. Caller deallocates all the scratch classes in case of
1005 // an error.
1006 _scratch_classes[i] = k;
1007
1008 if (HAS_PENDING_EXCEPTION) {
1009 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1010 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1011 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1012 ex_name->as_C_string()));
1013 CLEAR_PENDING_EXCEPTION;
1014
1015 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1016 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1017 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1018 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1019 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1020 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1021 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1022 // The message will be "XXX (wrong name: YYY)"
1023 return JVMTI_ERROR_NAMES_DONT_MATCH;
1024 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1025 return JVMTI_ERROR_OUT_OF_MEMORY;
1026 } else { // Just in case more exceptions can be thrown..
1027 return JVMTI_ERROR_FAILS_VERIFICATION;
1028 }
1029 }
1030
1031 // Ensure class is linked before redefine
1032 if (!the_class->is_linked()) {
1033 the_class->link_class(THREAD);
1034 if (HAS_PENDING_EXCEPTION) {
1035 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1036 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1037 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1038 ex_name->as_C_string()));
1039 CLEAR_PENDING_EXCEPTION;
1040 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1041 return JVMTI_ERROR_OUT_OF_MEMORY;
1042 } else {
1043 return JVMTI_ERROR_INTERNAL;
1044 }
1045 }
1046 }
1047
1048 // Do the validity checks in compare_and_normalize_class_versions()
1049 // before verifying the byte codes. By doing these checks first, we
1050 // limit the number of functions that require redirection from
1051 // the_class to scratch_class. In particular, we don't have to
1052 // modify JNI GetSuperclass() and thus won't change its performance.
1053 jvmtiError res = compare_and_normalize_class_versions(the_class,
1054 scratch_class);
1055 if (res != JVMTI_ERROR_NONE) {
1056 return res;
1057 }
1058
1059 // verify what the caller passed us
1060 {
1061 // The bug 6214132 caused the verification to fail.
1062 // Information about the_class and scratch_class is temporarily
1063 // recorded into jvmtiThreadState. This data is used to redirect
1064 // the_class to scratch_class in the JVM_* functions called by the
1065 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1066 // description.
1067 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1068 Verifier::verify(
1069 scratch_class, Verifier::ThrowException, true, THREAD);
1070 }
1071
1072 if (HAS_PENDING_EXCEPTION) {
1073 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1074 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1075 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1076 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1077 CLEAR_PENDING_EXCEPTION;
1078 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1079 return JVMTI_ERROR_OUT_OF_MEMORY;
1080 } else {
1081 // tell the caller the bytecodes are bad
1082 return JVMTI_ERROR_FAILS_VERIFICATION;
1083 }
1084 }
1085
1086 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1087 if (HAS_PENDING_EXCEPTION) {
1088 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1089 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1090 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1091 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1092 CLEAR_PENDING_EXCEPTION;
1093 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1094 return JVMTI_ERROR_OUT_OF_MEMORY;
1095 } else {
1096 return JVMTI_ERROR_INTERNAL;
1097 }
1098 }
1099
1100 if (VerifyMergedCPBytecodes) {
1101 // verify what we have done during constant pool merging
1102 {
1103 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1104 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1105 }
1106
1107 if (HAS_PENDING_EXCEPTION) {
1108 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1109 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1110 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1111 ("verify_byte_codes post merge-CP exception: '%s'",
1112 ex_name->as_C_string()));
1113 CLEAR_PENDING_EXCEPTION;
1114 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1115 return JVMTI_ERROR_OUT_OF_MEMORY;
1116 } else {
1117 // tell the caller that constant pool merging screwed up
1118 return JVMTI_ERROR_INTERNAL;
1119 }
1120 }
1121 }
1122
1123 Rewriter::rewrite(scratch_class, THREAD);
1124 if (!HAS_PENDING_EXCEPTION) {
1125 scratch_class->link_methods(THREAD);
1126 }
1127 if (HAS_PENDING_EXCEPTION) {
1128 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1129 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1130 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1131 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1132 CLEAR_PENDING_EXCEPTION;
1133 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1134 return JVMTI_ERROR_OUT_OF_MEMORY;
1135 } else {
1136 return JVMTI_ERROR_INTERNAL;
1137 }
1138 }
1139
1140 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1141 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1142 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1143 the_class->external_name(), os::available_memory() >> 10));
1144 }
1145
1146 return JVMTI_ERROR_NONE;
1147 }
1148
1149
1150 // Map old_index to new_index as needed. scratch_cp is only needed
1151 // for RC_TRACE() calls.
1152 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1153 int old_index, int new_index) {
1154 if (find_new_index(old_index) != 0) {
1155 // old_index is already mapped
1156 return;
1157 }
1158
1159 if (old_index == new_index) {
1160 // no mapping is needed
1161 return;
1162 }
1163
1164 _index_map_p->at_put(old_index, new_index);
1165 _index_map_count++;
1166
1167 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1168 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1169 } // end map_index()
1170
1171
1172 // Map old_index to new_index as needed.
1173 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1174 if (find_new_operand_index(old_index) != -1) {
1175 // old_index is already mapped
1176 return;
1177 }
1178
1179 if (old_index == new_index) {
1180 // no mapping is needed
1181 return;
1182 }
1183
1184 _operands_index_map_p->at_put(old_index, new_index);
1185 _operands_index_map_count++;
1186
1187 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1188 } // end map_index()
1189
1190
1191 // Merge old_cp and scratch_cp and return the results of the merge via
1192 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1193 // merge_cp_length_p. The entries in old_cp occupy the same locations
1194 // in *merge_cp_p. Also creates a map of indices from entries in
1195 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1196 // entries are only created for entries in scratch_cp that occupy a
1197 // different location in *merged_cp_p.
1198 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1199 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1200 int *merge_cp_length_p, TRAPS) {
1201
1202 if (merge_cp_p == NULL) {
1203 assert(false, "caller must provide scratch constantPool");
1204 return false; // robustness
1205 }
1206 if (merge_cp_length_p == NULL) {
1207 assert(false, "caller must provide scratch CP length");
1208 return false; // robustness
1209 }
1210 // Worst case we need old_cp->length() + scratch_cp()->length(),
1211 // but the caller might be smart so make sure we have at least
1212 // the minimum.
1213 if ((*merge_cp_p)->length() < old_cp->length()) {
1214 assert(false, "merge area too small");
1215 return false; // robustness
1216 }
1217
1218 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1219 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1220 scratch_cp->length()));
1221
1222 {
1223 // Pass 0:
1224 // The old_cp is copied to *merge_cp_p; this means that any code
1225 // using old_cp does not have to change. This work looks like a
1226 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1227 // handle one special case:
1228 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1229 // This will make verification happy.
1230
1231 int old_i; // index into old_cp
1232
1233 // index zero (0) is not used in constantPools
1234 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1235 // leave debugging crumb
1236 jbyte old_tag = old_cp->tag_at(old_i).value();
1237 switch (old_tag) {
1238 case JVM_CONSTANT_Class:
1239 case JVM_CONSTANT_UnresolvedClass:
1240 // revert the copy to JVM_CONSTANT_UnresolvedClass
1241 // May be resolving while calling this so do the same for
1242 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1243 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1244 old_cp->klass_name_at(old_i));
1245 break;
1246
1247 case JVM_CONSTANT_Double:
1248 case JVM_CONSTANT_Long:
1249 // just copy the entry to *merge_cp_p, but double and long take
1250 // two constant pool entries
1251 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1252 old_i++;
1253 break;
1254
1255 default:
1256 // just copy the entry to *merge_cp_p
1257 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1258 break;
1259 }
1260 } // end for each old_cp entry
1261
1262 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1263 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1264
1265 // We don't need to sanity check that *merge_cp_length_p is within
1266 // *merge_cp_p bounds since we have the minimum on-entry check above.
1267 (*merge_cp_length_p) = old_i;
1268 }
1269
1270 // merge_cp_len should be the same as old_cp->length() at this point
1271 // so this trace message is really a "warm-and-breathing" message.
1272 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1273 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1274
1275 int scratch_i; // index into scratch_cp
1276 {
1277 // Pass 1a:
1278 // Compare scratch_cp entries to the old_cp entries that we have
1279 // already copied to *merge_cp_p. In this pass, we are eliminating
1280 // exact duplicates (matching entry at same index) so we only
1281 // compare entries in the common indice range.
1282 int increment = 1;
1283 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1284 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1285 switch (scratch_cp->tag_at(scratch_i).value()) {
1286 case JVM_CONSTANT_Double:
1287 case JVM_CONSTANT_Long:
1288 // double and long take two constant pool entries
1289 increment = 2;
1290 break;
1291
1292 default:
1293 increment = 1;
1294 break;
1295 }
1296
1297 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1298 scratch_i, CHECK_0);
1299 if (match) {
1300 // found a match at the same index so nothing more to do
1301 continue;
1302 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1303 *merge_cp_p, scratch_i)) {
1304 // The mismatch in compare_entry_to() above is because of a
1305 // resolved versus unresolved class entry at the same index
1306 // with the same string value. Since Pass 0 reverted any
1307 // class entries to unresolved class entries in *merge_cp_p,
1308 // we go with the unresolved class entry.
1309 continue;
1310 }
1311
1312 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1313 CHECK_0);
1314 if (found_i != 0) {
1315 guarantee(found_i != scratch_i,
1316 "compare_entry_to() and find_matching_entry() do not agree");
1317
1318 // Found a matching entry somewhere else in *merge_cp_p so
1319 // just need a mapping entry.
1320 map_index(scratch_cp, scratch_i, found_i);
1321 continue;
1322 }
1323
1324 // The find_matching_entry() call above could fail to find a match
1325 // due to a resolved versus unresolved class or string entry situation
1326 // like we solved above with the is_unresolved_*_mismatch() calls.
1327 // However, we would have to call is_unresolved_*_mismatch() over
1328 // all of *merge_cp_p (potentially) and that doesn't seem to be
1329 // worth the time.
1330
1331 // No match found so we have to append this entry and any unique
1332 // referenced entries to *merge_cp_p.
1333 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1334 CHECK_0);
1335 }
1336 }
1337
1338 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1339 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1340 *merge_cp_length_p, scratch_i, _index_map_count));
1341
1342 if (scratch_i < scratch_cp->length()) {
1343 // Pass 1b:
1344 // old_cp is smaller than scratch_cp so there are entries in
1345 // scratch_cp that we have not yet processed. We take care of
1346 // those now.
1347 int increment = 1;
1348 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1349 switch (scratch_cp->tag_at(scratch_i).value()) {
1350 case JVM_CONSTANT_Double:
1351 case JVM_CONSTANT_Long:
1352 // double and long take two constant pool entries
1353 increment = 2;
1354 break;
1355
1356 default:
1357 increment = 1;
1358 break;
1359 }
1360
1361 int found_i =
1362 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1363 if (found_i != 0) {
1364 // Found a matching entry somewhere else in *merge_cp_p so
1365 // just need a mapping entry.
1366 map_index(scratch_cp, scratch_i, found_i);
1367 continue;
1368 }
1369
1370 // No match found so we have to append this entry and any unique
1371 // referenced entries to *merge_cp_p.
1372 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1373 CHECK_0);
1374 }
1375
1376 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1377 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1378 *merge_cp_length_p, scratch_i, _index_map_count));
1379 }
1380 finalize_operands_merge(*merge_cp_p, THREAD);
1381
1382 return true;
1383 } // end merge_constant_pools()
1384
1385
1386 // Scoped object to clean up the constant pool(s) created for merging
1387 class MergeCPCleaner {
1388 ClassLoaderData* _loader_data;
1389 ConstantPool* _cp;
1390 ConstantPool* _scratch_cp;
1391 public:
1392 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1393 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1394 ~MergeCPCleaner() {
1395 _loader_data->add_to_deallocate_list(_cp);
1396 if (_scratch_cp != NULL) {
1397 _loader_data->add_to_deallocate_list(_scratch_cp);
1398 }
1399 }
1400 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1401 };
1402
1403 // Merge constant pools between the_class and scratch_class and
1404 // potentially rewrite bytecodes in scratch_class to use the merged
1405 // constant pool.
1406 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1407 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1408 TRAPS) {
1409 // worst case merged constant pool length is old and new combined
1410 int merge_cp_length = the_class->constants()->length()
1411 + scratch_class->constants()->length();
1412
1413 // Constant pools are not easily reused so we allocate a new one
1414 // each time.
1415 // merge_cp is created unsafe for concurrent GC processing. It
1416 // should be marked safe before discarding it. Even though
1417 // garbage, if it crosses a card boundary, it may be scanned
1418 // in order to find the start of the first complete object on the card.
1419 ClassLoaderData* loader_data = the_class->class_loader_data();
1420 ConstantPool* merge_cp_oop =
1421 ConstantPool::allocate(loader_data,
1422 merge_cp_length,
1423 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1424 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1425
1426 HandleMark hm(THREAD); // make sure handles are cleared before
1427 // MergeCPCleaner clears out merge_cp_oop
1428 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1429
1430 // Get constants() from the old class because it could have been rewritten
1431 // while we were at a safepoint allocating a new constant pool.
1432 constantPoolHandle old_cp(THREAD, the_class->constants());
1433 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1434
1435 // If the length changed, the class was redefined out from under us. Return
1436 // an error.
1437 if (merge_cp_length != the_class->constants()->length()
1438 + scratch_class->constants()->length()) {
1439 return JVMTI_ERROR_INTERNAL;
1440 }
1441
1442 // Update the version number of the constant pool
1443 merge_cp->increment_and_save_version(old_cp->version());
1444
1445 ResourceMark rm(THREAD);
1446 _index_map_count = 0;
1447 _index_map_p = new intArray(scratch_cp->length(), -1);
1448
1449 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1450 _operands_index_map_count = 0;
1451 _operands_index_map_p = new intArray(
1452 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1453
1454 // reference to the cp holder is needed for copy_operands()
1455 merge_cp->set_pool_holder(scratch_class());
1456 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1457 &merge_cp_length, THREAD);
1458 merge_cp->set_pool_holder(NULL);
1459
1460 if (!result) {
1461 // The merge can fail due to memory allocation failure or due
1462 // to robustness checks.
1463 return JVMTI_ERROR_INTERNAL;
1464 }
1465
1466 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1467 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1468
1469 if (_index_map_count == 0) {
1470 // there is nothing to map between the new and merged constant pools
1471
1472 if (old_cp->length() == scratch_cp->length()) {
1473 // The old and new constant pools are the same length and the
1474 // index map is empty. This means that the three constant pools
1475 // are equivalent (but not the same). Unfortunately, the new
1476 // constant pool has not gone through link resolution nor have
1477 // the new class bytecodes gone through constant pool cache
1478 // rewriting so we can't use the old constant pool with the new
1479 // class.
1480
1481 // toss the merged constant pool at return
1482 } else if (old_cp->length() < scratch_cp->length()) {
1483 // The old constant pool has fewer entries than the new constant
1484 // pool and the index map is empty. This means the new constant
1485 // pool is a superset of the old constant pool. However, the old
1486 // class bytecodes have already gone through constant pool cache
1487 // rewriting so we can't use the new constant pool with the old
1488 // class.
1489
1490 // toss the merged constant pool at return
1491 } else {
1492 // The old constant pool has more entries than the new constant
1493 // pool and the index map is empty. This means that both the old
1494 // and merged constant pools are supersets of the new constant
1495 // pool.
1496
1497 // Replace the new constant pool with a shrunken copy of the
1498 // merged constant pool
1499 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1500 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1501 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1502 // It can't be cleaned up while there are handles to it.
1503 cp_cleaner.add_scratch_cp(scratch_cp());
1504 }
1505 } else {
1506 if (RC_TRACE_ENABLED(0x00040000)) {
1507 // don't want to loop unless we are tracing
1508 int count = 0;
1509 for (int i = 1; i < _index_map_p->length(); i++) {
1510 int value = _index_map_p->at(i);
1511
1512 if (value != -1) {
1513 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1514 ("index_map[%d]: old=%d new=%d", count, i, value));
1515 count++;
1516 }
1517 }
1518 }
1519
1520 // We have entries mapped between the new and merged constant pools
1521 // so we have to rewrite some constant pool references.
1522 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1523 return JVMTI_ERROR_INTERNAL;
1524 }
1525
1526 // Replace the new constant pool with a shrunken copy of the
1527 // merged constant pool so now the rewritten bytecodes have
1528 // valid references; the previous new constant pool will get
1529 // GCed.
1530 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1531 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1532 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1533 // It can't be cleaned up while there are handles to it.
1534 cp_cleaner.add_scratch_cp(scratch_cp());
1535 }
1536
1537 return JVMTI_ERROR_NONE;
1538 } // end merge_cp_and_rewrite()
1539
1540
1541 // Rewrite constant pool references in klass scratch_class.
1542 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1543 TRAPS) {
1544
1545 // rewrite constant pool references in the methods:
1546 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1547 // propagate failure back to caller
1548 return false;
1549 }
1550
1551 // rewrite constant pool references in the class_annotations:
1552 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1553 // propagate failure back to caller
1554 return false;
1555 }
1556
1557 // rewrite constant pool references in the fields_annotations:
1558 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1559 // propagate failure back to caller
1560 return false;
1561 }
1562
1563 // rewrite constant pool references in the methods_annotations:
1564 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1565 // propagate failure back to caller
1566 return false;
1567 }
1568
1569 // rewrite constant pool references in the methods_parameter_annotations:
1570 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1571 THREAD)) {
1572 // propagate failure back to caller
1573 return false;
1574 }
1575
1576 // rewrite constant pool references in the methods_default_annotations:
1577 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1578 THREAD)) {
1579 // propagate failure back to caller
1580 return false;
1581 }
1582
1583 // rewrite constant pool references in the class_type_annotations:
1584 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1585 // propagate failure back to caller
1586 return false;
1587 }
1588
1589 // rewrite constant pool references in the fields_type_annotations:
1590 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1591 // propagate failure back to caller
1592 return false;
1593 }
1594
1595 // rewrite constant pool references in the methods_type_annotations:
1596 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1597 // propagate failure back to caller
1598 return false;
1599 }
1600
1601 // There can be type annotations in the Code part of a method_info attribute.
1602 // These annotations are not accessible, even by reflection.
1603 // Currently they are not even parsed by the ClassFileParser.
1604 // If runtime access is added they will also need to be rewritten.
1605
1606 // rewrite source file name index:
1607 u2 source_file_name_idx = scratch_class->source_file_name_index();
1608 if (source_file_name_idx != 0) {
1609 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1610 if (new_source_file_name_idx != 0) {
1611 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1612 }
1613 }
1614
1615 // rewrite class generic signature index:
1616 u2 generic_signature_index = scratch_class->generic_signature_index();
1617 if (generic_signature_index != 0) {
1618 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1619 if (new_generic_signature_index != 0) {
1620 scratch_class->set_generic_signature_index(new_generic_signature_index);
1621 }
1622 }
1623
1624 return true;
1625 } // end rewrite_cp_refs()
1626
1627 // Rewrite constant pool references in the methods.
1628 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1629 instanceKlassHandle scratch_class, TRAPS) {
1630
1631 Array<Method*>* methods = scratch_class->methods();
1632
1633 if (methods == NULL || methods->length() == 0) {
1634 // no methods so nothing to do
1635 return true;
1636 }
1637
1638 // rewrite constant pool references in the methods:
1639 for (int i = methods->length() - 1; i >= 0; i--) {
1640 methodHandle method(THREAD, methods->at(i));
1641 methodHandle new_method;
1642 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1643 if (!new_method.is_null()) {
1644 // the method has been replaced so save the new method version
1645 // even in the case of an exception. original method is on the
1646 // deallocation list.
1647 methods->at_put(i, new_method());
1648 }
1649 if (HAS_PENDING_EXCEPTION) {
1650 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1651 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1652 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1653 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1654 // Need to clear pending exception here as the super caller sets
1655 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1656 CLEAR_PENDING_EXCEPTION;
1657 return false;
1658 }
1659 }
1660
1661 return true;
1662 }
1663
1664
1665 // Rewrite constant pool references in the specific method. This code
1666 // was adapted from Rewriter::rewrite_method().
1667 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1668 methodHandle *new_method_p, TRAPS) {
1669
1670 *new_method_p = methodHandle(); // default is no new method
1671
1672 // We cache a pointer to the bytecodes here in code_base. If GC
1673 // moves the Method*, then the bytecodes will also move which
1674 // will likely cause a crash. We create a No_Safepoint_Verifier
1675 // object to detect whether we pass a possible safepoint in this
1676 // code block.
1677 No_Safepoint_Verifier nsv;
1678
1679 // Bytecodes and their length
1680 address code_base = method->code_base();
1681 int code_length = method->code_size();
1682
1683 int bc_length;
1684 for (int bci = 0; bci < code_length; bci += bc_length) {
1685 address bcp = code_base + bci;
1686 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1687
1688 bc_length = Bytecodes::length_for(c);
1689 if (bc_length == 0) {
1690 // More complicated bytecodes report a length of zero so
1691 // we have to try again a slightly different way.
1692 bc_length = Bytecodes::length_at(method(), bcp);
1693 }
1694
1695 assert(bc_length != 0, "impossible bytecode length");
1696
1697 switch (c) {
1698 case Bytecodes::_ldc:
1699 {
1700 int cp_index = *(bcp + 1);
1701 int new_index = find_new_index(cp_index);
1702
1703 if (StressLdcRewrite && new_index == 0) {
1704 // If we are stressing ldc -> ldc_w rewriting, then we
1705 // always need a new_index value.
1706 new_index = cp_index;
1707 }
1708 if (new_index != 0) {
1709 // the original index is mapped so we have more work to do
1710 if (!StressLdcRewrite && new_index <= max_jubyte) {
1711 // The new value can still use ldc instead of ldc_w
1712 // unless we are trying to stress ldc -> ldc_w rewriting
1713 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1714 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1715 bcp, cp_index, new_index));
1716 *(bcp + 1) = new_index;
1717 } else {
1718 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1719 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1720 Bytecodes::name(c), bcp, cp_index, new_index));
1721 // the new value needs ldc_w instead of ldc
1722 u_char inst_buffer[4]; // max instruction size is 4 bytes
1723 bcp = (address)inst_buffer;
1724 // construct new instruction sequence
1725 *bcp = Bytecodes::_ldc_w;
1726 bcp++;
1727 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1728 // See comment below for difference between put_Java_u2()
1729 // and put_native_u2().
1730 Bytes::put_Java_u2(bcp, new_index);
1731
1732 Relocator rc(method, NULL /* no RelocatorListener needed */);
1733 methodHandle m;
1734 {
1735 Pause_No_Safepoint_Verifier pnsv(&nsv);
1736
1737 // ldc is 2 bytes and ldc_w is 3 bytes
1738 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1739 }
1740
1741 // return the new method so that the caller can update
1742 // the containing class
1743 *new_method_p = method = m;
1744 // switch our bytecode processing loop from the old method
1745 // to the new method
1746 code_base = method->code_base();
1747 code_length = method->code_size();
1748 bcp = code_base + bci;
1749 c = (Bytecodes::Code)(*bcp);
1750 bc_length = Bytecodes::length_for(c);
1751 assert(bc_length != 0, "sanity check");
1752 } // end we need ldc_w instead of ldc
1753 } // end if there is a mapped index
1754 } break;
1755
1756 // these bytecodes have a two-byte constant pool index
1757 case Bytecodes::_anewarray : // fall through
1758 case Bytecodes::_checkcast : // fall through
1759 case Bytecodes::_getfield : // fall through
1760 case Bytecodes::_getstatic : // fall through
1761 case Bytecodes::_instanceof : // fall through
1762 case Bytecodes::_invokedynamic : // fall through
1763 case Bytecodes::_invokeinterface: // fall through
1764 case Bytecodes::_invokespecial : // fall through
1765 case Bytecodes::_invokestatic : // fall through
1766 case Bytecodes::_invokevirtual : // fall through
1767 case Bytecodes::_ldc_w : // fall through
1768 case Bytecodes::_ldc2_w : // fall through
1769 case Bytecodes::_multianewarray : // fall through
1770 case Bytecodes::_new : // fall through
1771 case Bytecodes::_putfield : // fall through
1772 case Bytecodes::_putstatic :
1773 {
1774 address p = bcp + 1;
1775 int cp_index = Bytes::get_Java_u2(p);
1776 int new_index = find_new_index(cp_index);
1777 if (new_index != 0) {
1778 // the original index is mapped so update w/ new value
1779 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1780 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1781 bcp, cp_index, new_index));
1782 // Rewriter::rewrite_method() uses put_native_u2() in this
1783 // situation because it is reusing the constant pool index
1784 // location for a native index into the ConstantPoolCache.
1785 // Since we are updating the constant pool index prior to
1786 // verification and ConstantPoolCache initialization, we
1787 // need to keep the new index in Java byte order.
1788 Bytes::put_Java_u2(p, new_index);
1789 }
1790 } break;
1791 }
1792 } // end for each bytecode
1793
1794 // We also need to rewrite the parameter name indexes, if there is
1795 // method parameter data present
1796 if(method->has_method_parameters()) {
1797 const int len = method->method_parameters_length();
1798 MethodParametersElement* elem = method->method_parameters_start();
1799
1800 for (int i = 0; i < len; i++) {
1801 const u2 cp_index = elem[i].name_cp_index;
1802 const u2 new_cp_index = find_new_index(cp_index);
1803 if (new_cp_index != 0) {
1804 elem[i].name_cp_index = new_cp_index;
1805 }
1806 }
1807 }
1808 } // end rewrite_cp_refs_in_method()
1809
1810
1811 // Rewrite constant pool references in the class_annotations field.
1812 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1813 instanceKlassHandle scratch_class, TRAPS) {
1814
1815 AnnotationArray* class_annotations = scratch_class->class_annotations();
1816 if (class_annotations == NULL || class_annotations->length() == 0) {
1817 // no class_annotations so nothing to do
1818 return true;
1819 }
1820
1821 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1822 ("class_annotations length=%d", class_annotations->length()));
1823
1824 int byte_i = 0; // byte index into class_annotations
1825 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1826 THREAD);
1827 }
1828
1829
1830 // Rewrite constant pool references in an annotations typeArray. This
1831 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1832 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1833 //
1834 // annotations_typeArray {
1835 // u2 num_annotations;
1836 // annotation annotations[num_annotations];
1837 // }
1838 //
1839 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1840 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1841
1842 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1843 // not enough room for num_annotations field
1844 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1845 ("length() is too small for num_annotations field"));
1846 return false;
1847 }
1848
1849 u2 num_annotations = Bytes::get_Java_u2((address)
1850 annotations_typeArray->adr_at(byte_i_ref));
1851 byte_i_ref += 2;
1852
1853 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1854 ("num_annotations=%d", num_annotations));
1855
1856 int calc_num_annotations = 0;
1857 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1858 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1859 byte_i_ref, THREAD)) {
1860 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1861 ("bad annotation_struct at %d", calc_num_annotations));
1862 // propagate failure back to caller
1863 return false;
1864 }
1865 }
1866 assert(num_annotations == calc_num_annotations, "sanity check");
1867
1868 return true;
1869 } // end rewrite_cp_refs_in_annotations_typeArray()
1870
1871
1872 // Rewrite constant pool references in the annotation struct portion of
1873 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1874 // the 2nd-edition of the VM spec:
1875 //
1876 // struct annotation {
1877 // u2 type_index;
1878 // u2 num_element_value_pairs;
1879 // {
1880 // u2 element_name_index;
1881 // element_value value;
1882 // } element_value_pairs[num_element_value_pairs];
1883 // }
1884 //
1885 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1886 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1887 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1888 // not enough room for smallest annotation_struct
1889 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1890 ("length() is too small for annotation_struct"));
1891 return false;
1892 }
1893
1894 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1895 byte_i_ref, "mapped old type_index=%d", THREAD);
1896
1897 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1898 annotations_typeArray->adr_at(byte_i_ref));
1899 byte_i_ref += 2;
1900
1901 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1902 ("type_index=%d num_element_value_pairs=%d", type_index,
1903 num_element_value_pairs));
1904
1905 int calc_num_element_value_pairs = 0;
1906 for (; calc_num_element_value_pairs < num_element_value_pairs;
1907 calc_num_element_value_pairs++) {
1908 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1909 // not enough room for another element_name_index, let alone
1910 // the rest of another component
1911 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1912 ("length() is too small for element_name_index"));
1913 return false;
1914 }
1915
1916 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1917 annotations_typeArray, byte_i_ref,
1918 "mapped old element_name_index=%d", THREAD);
1919
1920 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1921 ("element_name_index=%d", element_name_index));
1922
1923 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1924 byte_i_ref, THREAD)) {
1925 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1926 ("bad element_value at %d", calc_num_element_value_pairs));
1927 // propagate failure back to caller
1928 return false;
1929 }
1930 } // end for each component
1931 assert(num_element_value_pairs == calc_num_element_value_pairs,
1932 "sanity check");
1933
1934 return true;
1935 } // end rewrite_cp_refs_in_annotation_struct()
1936
1937
1938 // Rewrite a constant pool reference at the current position in
1939 // annotations_typeArray if needed. Returns the original constant
1940 // pool reference if a rewrite was not needed or the new constant
1941 // pool reference if a rewrite was needed.
1942 PRAGMA_DIAG_PUSH
1943 PRAGMA_FORMAT_NONLITERAL_IGNORED
1944 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1945 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1946 const char * trace_mesg, TRAPS) {
1947
1948 address cp_index_addr = (address)
1949 annotations_typeArray->adr_at(byte_i_ref);
1950 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1951 u2 new_cp_index = find_new_index(old_cp_index);
1952 if (new_cp_index != 0) {
1953 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1954 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1955 old_cp_index = new_cp_index;
1956 }
1957 byte_i_ref += 2;
1958 return old_cp_index;
1959 }
1960 PRAGMA_DIAG_POP
1961
1962
1963 // Rewrite constant pool references in the element_value portion of an
1964 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1965 // the 2nd-edition of the VM spec:
1966 //
1967 // struct element_value {
1968 // u1 tag;
1969 // union {
1970 // u2 const_value_index;
1971 // {
1972 // u2 type_name_index;
1973 // u2 const_name_index;
1974 // } enum_const_value;
1975 // u2 class_info_index;
1976 // annotation annotation_value;
1977 // struct {
1978 // u2 num_values;
1979 // element_value values[num_values];
1980 // } array_value;
1981 // } value;
1982 // }
1983 //
1984 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1985 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1986
1987 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1988 // not enough room for a tag let alone the rest of an element_value
1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1990 ("length() is too small for a tag"));
1991 return false;
1992 }
1993
1994 u1 tag = annotations_typeArray->at(byte_i_ref);
1995 byte_i_ref++;
1996 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1997
1998 switch (tag) {
1999 // These BaseType tag values are from Table 4.2 in VM spec:
2000 case 'B': // byte
2001 case 'C': // char
2002 case 'D': // double
2003 case 'F': // float
2004 case 'I': // int
2005 case 'J': // long
2006 case 'S': // short
2007 case 'Z': // boolean
2008
2009 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2010 // the VM spec:
2011 case 's':
2012 {
2013 // For the above tag values (including the BaseType values),
2014 // value.const_value_index is right union field.
2015
2016 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2017 // not enough room for a const_value_index
2018 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2019 ("length() is too small for a const_value_index"));
2020 return false;
2021 }
2022
2023 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2024 annotations_typeArray, byte_i_ref,
2025 "mapped old const_value_index=%d", THREAD);
2026
2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2028 ("const_value_index=%d", const_value_index));
2029 } break;
2030
2031 case 'e':
2032 {
2033 // for the above tag value, value.enum_const_value is right union field
2034
2035 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2036 // not enough room for a enum_const_value
2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2038 ("length() is too small for a enum_const_value"));
2039 return false;
2040 }
2041
2042 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2043 annotations_typeArray, byte_i_ref,
2044 "mapped old type_name_index=%d", THREAD);
2045
2046 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2047 annotations_typeArray, byte_i_ref,
2048 "mapped old const_name_index=%d", THREAD);
2049
2050 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2051 ("type_name_index=%d const_name_index=%d", type_name_index,
2052 const_name_index));
2053 } break;
2054
2055 case 'c':
2056 {
2057 // for the above tag value, value.class_info_index is right union field
2058
2059 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2060 // not enough room for a class_info_index
2061 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2062 ("length() is too small for a class_info_index"));
2063 return false;
2064 }
2065
2066 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2067 annotations_typeArray, byte_i_ref,
2068 "mapped old class_info_index=%d", THREAD);
2069
2070 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2071 ("class_info_index=%d", class_info_index));
2072 } break;
2073
2074 case '@':
2075 // For the above tag value, value.attr_value is the right union
2076 // field. This is a nested annotation.
2077 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2078 byte_i_ref, THREAD)) {
2079 // propagate failure back to caller
2080 return false;
2081 }
2082 break;
2083
2084 case '[':
2085 {
2086 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2087 // not enough room for a num_values field
2088 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2089 ("length() is too small for a num_values field"));
2090 return false;
2091 }
2092
2093 // For the above tag value, value.array_value is the right union
2094 // field. This is an array of nested element_value.
2095 u2 num_values = Bytes::get_Java_u2((address)
2096 annotations_typeArray->adr_at(byte_i_ref));
2097 byte_i_ref += 2;
2098 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2099
2100 int calc_num_values = 0;
2101 for (; calc_num_values < num_values; calc_num_values++) {
2102 if (!rewrite_cp_refs_in_element_value(
2103 annotations_typeArray, byte_i_ref, THREAD)) {
2104 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2105 ("bad nested element_value at %d", calc_num_values));
2106 // propagate failure back to caller
2107 return false;
2108 }
2109 }
2110 assert(num_values == calc_num_values, "sanity check");
2111 } break;
2112
2113 default:
2114 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2115 return false;
2116 } // end decode tag field
2117
2118 return true;
2119 } // end rewrite_cp_refs_in_element_value()
2120
2121
2122 // Rewrite constant pool references in a fields_annotations field.
2123 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2124 instanceKlassHandle scratch_class, TRAPS) {
2125
2126 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2127
2128 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2129 // no fields_annotations so nothing to do
2130 return true;
2131 }
2132
2133 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2134 ("fields_annotations length=%d", fields_annotations->length()));
2135
2136 for (int i = 0; i < fields_annotations->length(); i++) {
2137 AnnotationArray* field_annotations = fields_annotations->at(i);
2138 if (field_annotations == NULL || field_annotations->length() == 0) {
2139 // this field does not have any annotations so skip it
2140 continue;
2141 }
2142
2143 int byte_i = 0; // byte index into field_annotations
2144 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2145 THREAD)) {
2146 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2147 ("bad field_annotations at %d", i));
2148 // propagate failure back to caller
2149 return false;
2150 }
2151 }
2152
2153 return true;
2154 } // end rewrite_cp_refs_in_fields_annotations()
2155
2156
2157 // Rewrite constant pool references in a methods_annotations field.
2158 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2159 instanceKlassHandle scratch_class, TRAPS) {
2160
2161 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2162 Method* m = scratch_class->methods()->at(i);
2163 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2164
2165 if (method_annotations == NULL || method_annotations->length() == 0) {
2166 // this method does not have any annotations so skip it
2167 continue;
2168 }
2169
2170 int byte_i = 0; // byte index into method_annotations
2171 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2172 THREAD)) {
2173 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2174 ("bad method_annotations at %d", i));
2175 // propagate failure back to caller
2176 return false;
2177 }
2178 }
2179
2180 return true;
2181 } // end rewrite_cp_refs_in_methods_annotations()
2182
2183
2184 // Rewrite constant pool references in a methods_parameter_annotations
2185 // field. This "structure" is adapted from the
2186 // RuntimeVisibleParameterAnnotations_attribute described in section
2187 // 4.8.17 of the 2nd-edition of the VM spec:
2188 //
2189 // methods_parameter_annotations_typeArray {
2190 // u1 num_parameters;
2191 // {
2192 // u2 num_annotations;
2193 // annotation annotations[num_annotations];
2194 // } parameter_annotations[num_parameters];
2195 // }
2196 //
2197 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2198 instanceKlassHandle scratch_class, TRAPS) {
2199
2200 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2201 Method* m = scratch_class->methods()->at(i);
2202 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2203 if (method_parameter_annotations == NULL
2204 || method_parameter_annotations->length() == 0) {
2205 // this method does not have any parameter annotations so skip it
2206 continue;
2207 }
2208
2209 if (method_parameter_annotations->length() < 1) {
2210 // not enough room for a num_parameters field
2211 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2212 ("length() is too small for a num_parameters field at %d", i));
2213 return false;
2214 }
2215
2216 int byte_i = 0; // byte index into method_parameter_annotations
2217
2218 u1 num_parameters = method_parameter_annotations->at(byte_i);
2219 byte_i++;
2220
2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2222 ("num_parameters=%d", num_parameters));
2223
2224 int calc_num_parameters = 0;
2225 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2226 if (!rewrite_cp_refs_in_annotations_typeArray(
2227 method_parameter_annotations, byte_i, THREAD)) {
2228 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2229 ("bad method_parameter_annotations at %d", calc_num_parameters));
2230 // propagate failure back to caller
2231 return false;
2232 }
2233 }
2234 assert(num_parameters == calc_num_parameters, "sanity check");
2235 }
2236
2237 return true;
2238 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2239
2240
2241 // Rewrite constant pool references in a methods_default_annotations
2242 // field. This "structure" is adapted from the AnnotationDefault_attribute
2243 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2244 //
2245 // methods_default_annotations_typeArray {
2246 // element_value default_value;
2247 // }
2248 //
2249 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2250 instanceKlassHandle scratch_class, TRAPS) {
2251
2252 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2253 Method* m = scratch_class->methods()->at(i);
2254 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2255 if (method_default_annotations == NULL
2256 || method_default_annotations->length() == 0) {
2257 // this method does not have any default annotations so skip it
2258 continue;
2259 }
2260
2261 int byte_i = 0; // byte index into method_default_annotations
2262
2263 if (!rewrite_cp_refs_in_element_value(
2264 method_default_annotations, byte_i, THREAD)) {
2265 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2266 ("bad default element_value at %d", i));
2267 // propagate failure back to caller
2268 return false;
2269 }
2270 }
2271
2272 return true;
2273 } // end rewrite_cp_refs_in_methods_default_annotations()
2274
2275
2276 // Rewrite constant pool references in a class_type_annotations field.
2277 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2278 instanceKlassHandle scratch_class, TRAPS) {
2279
2280 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2281 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2282 // no class_type_annotations so nothing to do
2283 return true;
2284 }
2285
2286 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2287 ("class_type_annotations length=%d", class_type_annotations->length()));
2288
2289 int byte_i = 0; // byte index into class_type_annotations
2290 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2291 byte_i, "ClassFile", THREAD);
2292 } // end rewrite_cp_refs_in_class_type_annotations()
2293
2294
2295 // Rewrite constant pool references in a fields_type_annotations field.
2296 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2297 instanceKlassHandle scratch_class, TRAPS) {
2298
2299 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2300 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2301 // no fields_type_annotations so nothing to do
2302 return true;
2303 }
2304
2305 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2306 ("fields_type_annotations length=%d", fields_type_annotations->length()));
2307
2308 for (int i = 0; i < fields_type_annotations->length(); i++) {
2309 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2310 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2311 // this field does not have any annotations so skip it
2312 continue;
2313 }
2314
2315 int byte_i = 0; // byte index into field_type_annotations
2316 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2317 byte_i, "field_info", THREAD)) {
2318 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2319 ("bad field_type_annotations at %d", i));
2320 // propagate failure back to caller
2321 return false;
2322 }
2323 }
2324
2325 return true;
2326 } // end rewrite_cp_refs_in_fields_type_annotations()
2327
2328
2329 // Rewrite constant pool references in a methods_type_annotations field.
2330 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2331 instanceKlassHandle scratch_class, TRAPS) {
2332
2333 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2334 Method* m = scratch_class->methods()->at(i);
2335 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2336
2337 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2338 // this method does not have any annotations so skip it
2339 continue;
2340 }
2341
2342 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2343 ("methods type_annotations length=%d", method_type_annotations->length()));
2344
2345 int byte_i = 0; // byte index into method_type_annotations
2346 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2347 byte_i, "method_info", THREAD)) {
2348 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2349 ("bad method_type_annotations at %d", i));
2350 // propagate failure back to caller
2351 return false;
2352 }
2353 }
2354
2355 return true;
2356 } // end rewrite_cp_refs_in_methods_type_annotations()
2357
2358
2359 // Rewrite constant pool references in a type_annotations
2360 // field. This "structure" is adapted from the
2361 // RuntimeVisibleTypeAnnotations_attribute described in
2362 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2363 //
2364 // type_annotations_typeArray {
2365 // u2 num_annotations;
2366 // type_annotation annotations[num_annotations];
2367 // }
2368 //
2369 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2370 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2371 const char * location_mesg, TRAPS) {
2372
2373 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2374 // not enough room for num_annotations field
2375 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2376 ("length() is too small for num_annotations field"));
2377 return false;
2378 }
2379
2380 u2 num_annotations = Bytes::get_Java_u2((address)
2381 type_annotations_typeArray->adr_at(byte_i_ref));
2382 byte_i_ref += 2;
2383
2384 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2385 ("num_type_annotations=%d", num_annotations));
2386
2387 int calc_num_annotations = 0;
2388 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2389 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2390 byte_i_ref, location_mesg, THREAD)) {
2391 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2392 ("bad type_annotation_struct at %d", calc_num_annotations));
2393 // propagate failure back to caller
2394 return false;
2395 }
2396 }
2397 assert(num_annotations == calc_num_annotations, "sanity check");
2398
2399 if (byte_i_ref != type_annotations_typeArray->length()) {
2400 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2401 ("read wrong amount of bytes at end of processing "
2402 "type_annotations_typeArray (%d of %d bytes were read)",
2403 byte_i_ref, type_annotations_typeArray->length()));
2404 return false;
2405 }
2406
2407 return true;
2408 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2409
2410
2411 // Rewrite constant pool references in a type_annotation
2412 // field. This "structure" is adapted from the
2413 // RuntimeVisibleTypeAnnotations_attribute described in
2414 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2415 //
2416 // type_annotation {
2417 // u1 target_type;
2418 // union {
2419 // type_parameter_target;
2420 // supertype_target;
2421 // type_parameter_bound_target;
2422 // empty_target;
2423 // method_formal_parameter_target;
2424 // throws_target;
2425 // localvar_target;
2426 // catch_target;
2427 // offset_target;
2428 // type_argument_target;
2429 // } target_info;
2430 // type_path target_path;
2431 // annotation anno;
2432 // }
2433 //
2434 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2435 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2436 const char * location_mesg, TRAPS) {
2437
2438 if (!skip_type_annotation_target(type_annotations_typeArray,
2439 byte_i_ref, location_mesg, THREAD)) {
2440 return false;
2441 }
2442
2443 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2444 byte_i_ref, THREAD)) {
2445 return false;
2446 }
2447
2448 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2449 byte_i_ref, THREAD)) {
2450 return false;
2451 }
2452
2453 return true;
2454 } // end rewrite_cp_refs_in_type_annotation_struct()
2455
2456
2457 // Read, verify and skip over the target_type and target_info part
2458 // so that rewriting can continue in the later parts of the struct.
2459 //
2460 // u1 target_type;
2461 // union {
2462 // type_parameter_target;
2463 // supertype_target;
2464 // type_parameter_bound_target;
2465 // empty_target;
2466 // method_formal_parameter_target;
2467 // throws_target;
2468 // localvar_target;
2469 // catch_target;
2470 // offset_target;
2471 // type_argument_target;
2472 // } target_info;
2473 //
2474 bool VM_RedefineClasses::skip_type_annotation_target(
2475 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2476 const char * location_mesg, TRAPS) {
2477
2478 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2479 // not enough room for a target_type let alone the rest of a type_annotation
2480 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2481 ("length() is too small for a target_type"));
2482 return false;
2483 }
2484
2485 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2486 byte_i_ref += 1;
2487 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type));
2488 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg));
2489
2490 // Skip over target_info
2491 switch (target_type) {
2492 case 0x00:
2493 // kind: type parameter declaration of generic class or interface
2494 // location: ClassFile
2495 case 0x01:
2496 // kind: type parameter declaration of generic method or constructor
2497 // location: method_info
2498
2499 {
2500 // struct:
2501 // type_parameter_target {
2502 // u1 type_parameter_index;
2503 // }
2504 //
2505 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2506 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2507 ("length() is too small for a type_parameter_target"));
2508 return false;
2509 }
2510
2511 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2512 byte_i_ref += 1;
2513
2514 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2515 ("type_parameter_target: type_parameter_index=%d",
2516 type_parameter_index));
2517 } break;
2518
2519 case 0x10:
2520 // kind: type in extends clause of class or interface declaration
2521 // (including the direct superclass of an anonymous class declaration),
2522 // or in implements clause of interface declaration
2523 // location: ClassFile
2524
2525 {
2526 // struct:
2527 // supertype_target {
2528 // u2 supertype_index;
2529 // }
2530 //
2531 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2532 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2533 ("length() is too small for a supertype_target"));
2534 return false;
2535 }
2536
2537 u2 supertype_index = Bytes::get_Java_u2((address)
2538 type_annotations_typeArray->adr_at(byte_i_ref));
2539 byte_i_ref += 2;
2540
2541 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2542 ("supertype_target: supertype_index=%d", supertype_index));
2543 } break;
2544
2545 case 0x11:
2546 // kind: type in bound of type parameter declaration of generic class or interface
2547 // location: ClassFile
2548 case 0x12:
2549 // kind: type in bound of type parameter declaration of generic method or constructor
2550 // location: method_info
2551
2552 {
2553 // struct:
2554 // type_parameter_bound_target {
2555 // u1 type_parameter_index;
2556 // u1 bound_index;
2557 // }
2558 //
2559 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2560 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2561 ("length() is too small for a type_parameter_bound_target"));
2562 return false;
2563 }
2564
2565 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2566 byte_i_ref += 1;
2567 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2568 byte_i_ref += 1;
2569
2570 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2571 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d",
2572 type_parameter_index, bound_index));
2573 } break;
2574
2575 case 0x13:
2576 // kind: type in field declaration
2577 // location: field_info
2578 case 0x14:
2579 // kind: return type of method, or type of newly constructed object
2580 // location: method_info
2581 case 0x15:
2582 // kind: receiver type of method or constructor
2583 // location: method_info
2584
2585 {
2586 // struct:
2587 // empty_target {
2588 // }
2589 //
2590 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2591 ("empty_target"));
2592 } break;
2593
2594 case 0x16:
2595 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2596 // location: method_info
2597
2598 {
2599 // struct:
2600 // formal_parameter_target {
2601 // u1 formal_parameter_index;
2602 // }
2603 //
2604 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2605 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2606 ("length() is too small for a formal_parameter_target"));
2607 return false;
2608 }
2609
2610 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2611 byte_i_ref += 1;
2612
2613 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2614 ("formal_parameter_target: formal_parameter_index=%d",
2615 formal_parameter_index));
2616 } break;
2617
2618 case 0x17:
2619 // kind: type in throws clause of method or constructor
2620 // location: method_info
2621
2622 {
2623 // struct:
2624 // throws_target {
2625 // u2 throws_type_index
2626 // }
2627 //
2628 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2629 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2630 ("length() is too small for a throws_target"));
2631 return false;
2632 }
2633
2634 u2 throws_type_index = Bytes::get_Java_u2((address)
2635 type_annotations_typeArray->adr_at(byte_i_ref));
2636 byte_i_ref += 2;
2637
2638 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2639 ("throws_target: throws_type_index=%d", throws_type_index));
2640 } break;
2641
2642 case 0x40:
2643 // kind: type in local variable declaration
2644 // location: Code
2645 case 0x41:
2646 // kind: type in resource variable declaration
2647 // location: Code
2648
2649 {
2650 // struct:
2651 // localvar_target {
2652 // u2 table_length;
2653 // struct {
2654 // u2 start_pc;
2655 // u2 length;
2656 // u2 index;
2657 // } table[table_length];
2658 // }
2659 //
2660 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2661 // not enough room for a table_length let alone the rest of a localvar_target
2662 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2663 ("length() is too small for a localvar_target table_length"));
2664 return false;
2665 }
2666
2667 u2 table_length = Bytes::get_Java_u2((address)
2668 type_annotations_typeArray->adr_at(byte_i_ref));
2669 byte_i_ref += 2;
2670
2671 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2672 ("localvar_target: table_length=%d", table_length));
2673
2674 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2675 int table_size = table_length * table_struct_size;
2676
2677 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2678 // not enough room for a table
2679 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2680 ("length() is too small for a table array of length %d", table_length));
2681 return false;
2682 }
2683
2684 // Skip over table
2685 byte_i_ref += table_size;
2686 } break;
2687
2688 case 0x42:
2689 // kind: type in exception parameter declaration
2690 // location: Code
2691
2692 {
2693 // struct:
2694 // catch_target {
2695 // u2 exception_table_index;
2696 // }
2697 //
2698 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2699 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2700 ("length() is too small for a catch_target"));
2701 return false;
2702 }
2703
2704 u2 exception_table_index = Bytes::get_Java_u2((address)
2705 type_annotations_typeArray->adr_at(byte_i_ref));
2706 byte_i_ref += 2;
2707
2708 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2709 ("catch_target: exception_table_index=%d", exception_table_index));
2710 } break;
2711
2712 case 0x43:
2713 // kind: type in instanceof expression
2714 // location: Code
2715 case 0x44:
2716 // kind: type in new expression
2717 // location: Code
2718 case 0x45:
2719 // kind: type in method reference expression using ::new
2720 // location: Code
2721 case 0x46:
2722 // kind: type in method reference expression using ::Identifier
2723 // location: Code
2724
2725 {
2726 // struct:
2727 // offset_target {
2728 // u2 offset;
2729 // }
2730 //
2731 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2732 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2733 ("length() is too small for a offset_target"));
2734 return false;
2735 }
2736
2737 u2 offset = Bytes::get_Java_u2((address)
2738 type_annotations_typeArray->adr_at(byte_i_ref));
2739 byte_i_ref += 2;
2740
2741 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2742 ("offset_target: offset=%d", offset));
2743 } break;
2744
2745 case 0x47:
2746 // kind: type in cast expression
2747 // location: Code
2748 case 0x48:
2749 // kind: type argument for generic constructor in new expression or
2750 // explicit constructor invocation statement
2751 // location: Code
2752 case 0x49:
2753 // kind: type argument for generic method in method invocation expression
2754 // location: Code
2755 case 0x4A:
2756 // kind: type argument for generic constructor in method reference expression using ::new
2757 // location: Code
2758 case 0x4B:
2759 // kind: type argument for generic method in method reference expression using ::Identifier
2760 // location: Code
2761
2762 {
2763 // struct:
2764 // type_argument_target {
2765 // u2 offset;
2766 // u1 type_argument_index;
2767 // }
2768 //
2769 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2770 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2771 ("length() is too small for a type_argument_target"));
2772 return false;
2773 }
2774
2775 u2 offset = Bytes::get_Java_u2((address)
2776 type_annotations_typeArray->adr_at(byte_i_ref));
2777 byte_i_ref += 2;
2778 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2779 byte_i_ref += 1;
2780
2781 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2782 ("type_argument_target: offset=%d, type_argument_index=%d",
2783 offset, type_argument_index));
2784 } break;
2785
2786 default:
2787 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2788 ("unknown target_type"));
2789 #ifdef ASSERT
2790 ShouldNotReachHere();
2791 #endif
2792 return false;
2793 }
2794
2795 return true;
2796 } // end skip_type_annotation_target()
2797
2798
2799 // Read, verify and skip over the type_path part so that rewriting
2800 // can continue in the later parts of the struct.
2801 //
2802 // type_path {
2803 // u1 path_length;
2804 // {
2805 // u1 type_path_kind;
2806 // u1 type_argument_index;
2807 // } path[path_length];
2808 // }
2809 //
2810 bool VM_RedefineClasses::skip_type_annotation_type_path(
2811 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2812
2813 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2814 // not enough room for a path_length let alone the rest of the type_path
2815 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2816 ("length() is too small for a type_path"));
2817 return false;
2818 }
2819
2820 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2821 byte_i_ref += 1;
2822
2823 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2824 ("type_path: path_length=%d", path_length));
2825
2826 int calc_path_length = 0;
2827 for (; calc_path_length < path_length; calc_path_length++) {
2828 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2829 // not enough room for a path
2830 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2831 ("length() is too small for path entry %d of %d",
2832 calc_path_length, path_length));
2833 return false;
2834 }
2835
2836 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2837 byte_i_ref += 1;
2838 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2839 byte_i_ref += 1;
2840
2841 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2842 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2843 calc_path_length, type_path_kind, type_argument_index));
2844
2845 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2846 // not enough room for a path
2847 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2848 ("inconsistent type_path values"));
2849 return false;
2850 }
2851 }
2852 assert(path_length == calc_path_length, "sanity check");
2853
2854 return true;
2855 } // end skip_type_annotation_type_path()
2856
2857
2858 // Rewrite constant pool references in the method's stackmap table.
2859 // These "structures" are adapted from the StackMapTable_attribute that
2860 // is described in section 4.8.4 of the 6.0 version of the VM spec
2861 // (dated 2005.10.26):
2862 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2863 //
2864 // stack_map {
2865 // u2 number_of_entries;
2866 // stack_map_frame entries[number_of_entries];
2867 // }
2868 //
2869 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2870 methodHandle method, TRAPS) {
2871
2872 if (!method->has_stackmap_table()) {
2873 return;
2874 }
2875
2876 AnnotationArray* stackmap_data = method->stackmap_data();
2877 address stackmap_p = (address)stackmap_data->adr_at(0);
2878 address stackmap_end = stackmap_p + stackmap_data->length();
2879
2880 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2881 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2882 stackmap_p += 2;
2883
2884 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2885 ("number_of_entries=%u", number_of_entries));
2886
2887 // walk through each stack_map_frame
2888 u2 calc_number_of_entries = 0;
2889 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2890 // The stack_map_frame structure is a u1 frame_type followed by
2891 // 0 or more bytes of data:
2892 //
2893 // union stack_map_frame {
2894 // same_frame;
2895 // same_locals_1_stack_item_frame;
2896 // same_locals_1_stack_item_frame_extended;
2897 // chop_frame;
2898 // same_frame_extended;
2899 // append_frame;
2900 // full_frame;
2901 // }
2902
2903 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2904 // The Linux compiler does not like frame_type to be u1 or u2. It
2905 // issues the following warning for the first if-statement below:
2906 //
2907 // "warning: comparison is always true due to limited range of data type"
2908 //
2909 u4 frame_type = *stackmap_p;
2910 stackmap_p++;
2911
2912 // same_frame {
2913 // u1 frame_type = SAME; /* 0-63 */
2914 // }
2915 if (frame_type >= 0 && frame_type <= 63) {
2916 // nothing more to do for same_frame
2917 }
2918
2919 // same_locals_1_stack_item_frame {
2920 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2921 // verification_type_info stack[1];
2922 // }
2923 else if (frame_type >= 64 && frame_type <= 127) {
2924 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2925 calc_number_of_entries, frame_type, THREAD);
2926 }
2927
2928 // reserved for future use
2929 else if (frame_type >= 128 && frame_type <= 246) {
2930 // nothing more to do for reserved frame_types
2931 }
2932
2933 // same_locals_1_stack_item_frame_extended {
2934 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2935 // u2 offset_delta;
2936 // verification_type_info stack[1];
2937 // }
2938 else if (frame_type == 247) {
2939 stackmap_p += 2;
2940 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2941 calc_number_of_entries, frame_type, THREAD);
2942 }
2943
2944 // chop_frame {
2945 // u1 frame_type = CHOP; /* 248-250 */
2946 // u2 offset_delta;
2947 // }
2948 else if (frame_type >= 248 && frame_type <= 250) {
2949 stackmap_p += 2;
2950 }
2951
2952 // same_frame_extended {
2953 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2954 // u2 offset_delta;
2955 // }
2956 else if (frame_type == 251) {
2957 stackmap_p += 2;
2958 }
2959
2960 // append_frame {
2961 // u1 frame_type = APPEND; /* 252-254 */
2962 // u2 offset_delta;
2963 // verification_type_info locals[frame_type - 251];
2964 // }
2965 else if (frame_type >= 252 && frame_type <= 254) {
2966 assert(stackmap_p + 2 <= stackmap_end,
2967 "no room for offset_delta");
2968 stackmap_p += 2;
2969 u1 len = frame_type - 251;
2970 for (u1 i = 0; i < len; i++) {
2971 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2972 calc_number_of_entries, frame_type, THREAD);
2973 }
2974 }
2975
2976 // full_frame {
2977 // u1 frame_type = FULL_FRAME; /* 255 */
2978 // u2 offset_delta;
2979 // u2 number_of_locals;
2980 // verification_type_info locals[number_of_locals];
2981 // u2 number_of_stack_items;
2982 // verification_type_info stack[number_of_stack_items];
2983 // }
2984 else if (frame_type == 255) {
2985 assert(stackmap_p + 2 + 2 <= stackmap_end,
2986 "no room for smallest full_frame");
2987 stackmap_p += 2;
2988
2989 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2990 stackmap_p += 2;
2991
2992 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2993 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2994 calc_number_of_entries, frame_type, THREAD);
2995 }
2996
2997 // Use the largest size for the number_of_stack_items, but only get
2998 // the right number of bytes.
2999 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3000 stackmap_p += 2;
3001
3002 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3003 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3004 calc_number_of_entries, frame_type, THREAD);
3005 }
3006 }
3007 } // end while there is a stack_map_frame
3008 assert(number_of_entries == calc_number_of_entries, "sanity check");
3009 } // end rewrite_cp_refs_in_stack_map_table()
3010
3011
3012 // Rewrite constant pool references in the verification type info
3013 // portion of the method's stackmap table. These "structures" are
3014 // adapted from the StackMapTable_attribute that is described in
3015 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3016 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3017 //
3018 // The verification_type_info structure is a u1 tag followed by 0 or
3019 // more bytes of data:
3020 //
3021 // union verification_type_info {
3022 // Top_variable_info;
3023 // Integer_variable_info;
3024 // Float_variable_info;
3025 // Long_variable_info;
3026 // Double_variable_info;
3027 // Null_variable_info;
3028 // UninitializedThis_variable_info;
3029 // Object_variable_info;
3030 // Uninitialized_variable_info;
3031 // }
3032 //
3033 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3034 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3035 u1 frame_type, TRAPS) {
3036
3037 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3038 u1 tag = *stackmap_p_ref;
3039 stackmap_p_ref++;
3040
3041 switch (tag) {
3042 // Top_variable_info {
3043 // u1 tag = ITEM_Top; /* 0 */
3044 // }
3045 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3046 case 0: // fall through
3047
3048 // Integer_variable_info {
3049 // u1 tag = ITEM_Integer; /* 1 */
3050 // }
3051 case ITEM_Integer: // fall through
3052
3053 // Float_variable_info {
3054 // u1 tag = ITEM_Float; /* 2 */
3055 // }
3056 case ITEM_Float: // fall through
3057
3058 // Double_variable_info {
3059 // u1 tag = ITEM_Double; /* 3 */
3060 // }
3061 case ITEM_Double: // fall through
3062
3063 // Long_variable_info {
3064 // u1 tag = ITEM_Long; /* 4 */
3065 // }
3066 case ITEM_Long: // fall through
3067
3068 // Null_variable_info {
3069 // u1 tag = ITEM_Null; /* 5 */
3070 // }
3071 case ITEM_Null: // fall through
3072
3073 // UninitializedThis_variable_info {
3074 // u1 tag = ITEM_UninitializedThis; /* 6 */
3075 // }
3076 case ITEM_UninitializedThis:
3077 // nothing more to do for the above tag types
3078 break;
3079
3080 // Object_variable_info {
3081 // u1 tag = ITEM_Object; /* 7 */
3082 // u2 cpool_index;
3083 // }
3084 case ITEM_Object:
3085 {
3086 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3087 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3088 u2 new_cp_index = find_new_index(cpool_index);
3089 if (new_cp_index != 0) {
3090 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3091 ("mapped old cpool_index=%d", cpool_index));
3092 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3093 cpool_index = new_cp_index;
3094 }
3095 stackmap_p_ref += 2;
3096
3097 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3098 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
3099 frame_type, cpool_index));
3100 } break;
3101
3102 // Uninitialized_variable_info {
3103 // u1 tag = ITEM_Uninitialized; /* 8 */
3104 // u2 offset;
3105 // }
3106 case ITEM_Uninitialized:
3107 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3108 stackmap_p_ref += 2;
3109 break;
3110
3111 default:
3112 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3113 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
3114 ShouldNotReachHere();
3115 break;
3116 } // end switch (tag)
3117 } // end rewrite_cp_refs_in_verification_type_info()
3118
3119
3120 // Change the constant pool associated with klass scratch_class to
3121 // scratch_cp. If shrink is true, then scratch_cp_length elements
3122 // are copied from scratch_cp to a smaller constant pool and the
3123 // smaller constant pool is associated with scratch_class.
3124 void VM_RedefineClasses::set_new_constant_pool(
3125 ClassLoaderData* loader_data,
3126 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
3127 int scratch_cp_length, TRAPS) {
3128 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3129
3130 // scratch_cp is a merged constant pool and has enough space for a
3131 // worst case merge situation. We want to associate the minimum
3132 // sized constant pool with the klass to save space.
3133 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3134 constantPoolHandle smaller_cp(THREAD, cp);
3135
3136 // preserve version() value in the smaller copy
3137 int version = scratch_cp->version();
3138 assert(version != 0, "sanity check");
3139 smaller_cp->set_version(version);
3140
3141 // attach klass to new constant pool
3142 // reference to the cp holder is needed for copy_operands()
3143 smaller_cp->set_pool_holder(scratch_class());
3144
3145 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3146 if (HAS_PENDING_EXCEPTION) {
3147 // Exception is handled in the caller
3148 loader_data->add_to_deallocate_list(smaller_cp());
3149 return;
3150 }
3151 scratch_cp = smaller_cp;
3152
3153 // attach new constant pool to klass
3154 scratch_class->set_constants(scratch_cp());
3155
3156 int i; // for portability
3157
3158 // update each field in klass to use new constant pool indices as needed
3159 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3160 jshort cur_index = fs.name_index();
3161 jshort new_index = find_new_index(cur_index);
3162 if (new_index != 0) {
3163 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3164 ("field-name_index change: %d to %d", cur_index, new_index));
3165 fs.set_name_index(new_index);
3166 }
3167 cur_index = fs.signature_index();
3168 new_index = find_new_index(cur_index);
3169 if (new_index != 0) {
3170 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3171 ("field-signature_index change: %d to %d", cur_index, new_index));
3172 fs.set_signature_index(new_index);
3173 }
3174 cur_index = fs.initval_index();
3175 new_index = find_new_index(cur_index);
3176 if (new_index != 0) {
3177 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3178 ("field-initval_index change: %d to %d", cur_index, new_index));
3179 fs.set_initval_index(new_index);
3180 }
3181 cur_index = fs.generic_signature_index();
3182 new_index = find_new_index(cur_index);
3183 if (new_index != 0) {
3184 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3185 ("field-generic_signature change: %d to %d", cur_index, new_index));
3186 fs.set_generic_signature_index(new_index);
3187 }
3188 } // end for each field
3189
3190 // Update constant pool indices in the inner classes info to use
3191 // new constant indices as needed. The inner classes info is a
3192 // quadruple:
3193 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3194 InnerClassesIterator iter(scratch_class);
3195 for (; !iter.done(); iter.next()) {
3196 int cur_index = iter.inner_class_info_index();
3197 if (cur_index == 0) {
3198 continue; // JVM spec. allows null inner class refs so skip it
3199 }
3200 int new_index = find_new_index(cur_index);
3201 if (new_index != 0) {
3202 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3203 ("inner_class_info change: %d to %d", cur_index, new_index));
3204 iter.set_inner_class_info_index(new_index);
3205 }
3206 cur_index = iter.outer_class_info_index();
3207 new_index = find_new_index(cur_index);
3208 if (new_index != 0) {
3209 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3210 ("outer_class_info change: %d to %d", cur_index, new_index));
3211 iter.set_outer_class_info_index(new_index);
3212 }
3213 cur_index = iter.inner_name_index();
3214 new_index = find_new_index(cur_index);
3215 if (new_index != 0) {
3216 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3217 ("inner_name change: %d to %d", cur_index, new_index));
3218 iter.set_inner_name_index(new_index);
3219 }
3220 } // end for each inner class
3221
3222 // Attach each method in klass to the new constant pool and update
3223 // to use new constant pool indices as needed:
3224 Array<Method*>* methods = scratch_class->methods();
3225 for (i = methods->length() - 1; i >= 0; i--) {
3226 methodHandle method(THREAD, methods->at(i));
3227 method->set_constants(scratch_cp());
3228
3229 int new_index = find_new_index(method->name_index());
3230 if (new_index != 0) {
3231 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3232 ("method-name_index change: %d to %d", method->name_index(),
3233 new_index));
3234 method->set_name_index(new_index);
3235 }
3236 new_index = find_new_index(method->signature_index());
3237 if (new_index != 0) {
3238 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3239 ("method-signature_index change: %d to %d",
3240 method->signature_index(), new_index));
3241 method->set_signature_index(new_index);
3242 }
3243 new_index = find_new_index(method->generic_signature_index());
3244 if (new_index != 0) {
3245 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3246 ("method-generic_signature_index change: %d to %d",
3247 method->generic_signature_index(), new_index));
3248 method->set_generic_signature_index(new_index);
3249 }
3250
3251 // Update constant pool indices in the method's checked exception
3252 // table to use new constant indices as needed.
3253 int cext_length = method->checked_exceptions_length();
3254 if (cext_length > 0) {
3255 CheckedExceptionElement * cext_table =
3256 method->checked_exceptions_start();
3257 for (int j = 0; j < cext_length; j++) {
3258 int cur_index = cext_table[j].class_cp_index;
3259 int new_index = find_new_index(cur_index);
3260 if (new_index != 0) {
3261 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3262 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
3263 cext_table[j].class_cp_index = (u2)new_index;
3264 }
3265 } // end for each checked exception table entry
3266 } // end if there are checked exception table entries
3267
3268 // Update each catch type index in the method's exception table
3269 // to use new constant pool indices as needed. The exception table
3270 // holds quadruple entries of the form:
3271 // (beg_bci, end_bci, handler_bci, klass_index)
3272
3273 ExceptionTable ex_table(method());
3274 int ext_length = ex_table.length();
3275
3276 for (int j = 0; j < ext_length; j ++) {
3277 int cur_index = ex_table.catch_type_index(j);
3278 int new_index = find_new_index(cur_index);
3279 if (new_index != 0) {
3280 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3281 ("ext-klass_index change: %d to %d", cur_index, new_index));
3282 ex_table.set_catch_type_index(j, new_index);
3283 }
3284 } // end for each exception table entry
3285
3286 // Update constant pool indices in the method's local variable
3287 // table to use new constant indices as needed. The local variable
3288 // table hold sextuple entries of the form:
3289 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3290 int lvt_length = method->localvariable_table_length();
3291 if (lvt_length > 0) {
3292 LocalVariableTableElement * lv_table =
3293 method->localvariable_table_start();
3294 for (int j = 0; j < lvt_length; j++) {
3295 int cur_index = lv_table[j].name_cp_index;
3296 int new_index = find_new_index(cur_index);
3297 if (new_index != 0) {
3298 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3299 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
3300 lv_table[j].name_cp_index = (u2)new_index;
3301 }
3302 cur_index = lv_table[j].descriptor_cp_index;
3303 new_index = find_new_index(cur_index);
3304 if (new_index != 0) {
3305 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3306 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
3307 new_index));
3308 lv_table[j].descriptor_cp_index = (u2)new_index;
3309 }
3310 cur_index = lv_table[j].signature_cp_index;
3311 new_index = find_new_index(cur_index);
3312 if (new_index != 0) {
3313 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3314 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
3315 lv_table[j].signature_cp_index = (u2)new_index;
3316 }
3317 } // end for each local variable table entry
3318 } // end if there are local variable table entries
3319
3320 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3321 } // end for each method
3322 } // end set_new_constant_pool()
3323
3324
3325 // Unevolving classes may point to methods of the_class directly
3326 // from their constant pool caches, itables, and/or vtables. We
3327 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3328 // to fix up these pointers.
3329
3330 // Adjust cpools and vtables closure
3331 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3332
3333 // This is a very busy routine. We don't want too much tracing
3334 // printed out.
3335 bool trace_name_printed = false;
3336 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop);
3337
3338 // Very noisy: only enable this call if you are trying to determine
3339 // that a specific class gets found by this routine.
3340 // RC_TRACE macro has an embedded ResourceMark
3341 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
3342 // ("adjust check: name=%s", k->external_name()));
3343 // trace_name_printed = true;
3344
3345 // If the class being redefined is java.lang.Object, we need to fix all
3346 // array class vtables also
3347 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
3348 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3349
3350 } else if (k->oop_is_instance()) {
3351 HandleMark hm(_thread);
3352 InstanceKlass *ik = InstanceKlass::cast(k);
3353
3354 // HotSpot specific optimization! HotSpot does not currently
3355 // support delegation from the bootstrap class loader to a
3356 // user-defined class loader. This means that if the bootstrap
3357 // class loader is the initiating class loader, then it will also
3358 // be the defining class loader. This also means that classes
3359 // loaded by the bootstrap class loader cannot refer to classes
3360 // loaded by a user-defined class loader. Note: a user-defined
3361 // class loader can delegate to the bootstrap class loader.
3362 //
3363 // If the current class being redefined has a user-defined class
3364 // loader as its defining class loader, then we can skip all
3365 // classes loaded by the bootstrap class loader.
3366 bool is_user_defined =
3367 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
3368 if (is_user_defined && ik->class_loader() == NULL) {
3369 return;
3370 }
3371
3372 // Fix the vtable embedded in the_class and subclasses of the_class,
3373 // if one exists. We discard scratch_class and we don't keep an
3374 // InstanceKlass around to hold obsolete methods so we don't have
3375 // any other InstanceKlass embedded vtables to update. The vtable
3376 // holds the Method*s for virtual (but not final) methods.
3377 // Default methods, or concrete methods in interfaces are stored
3378 // in the vtable, so if an interface changes we need to check
3379 // adjust_method_entries() for every InstanceKlass, which will also
3380 // adjust the default method vtable indices.
3381 // We also need to adjust any default method entries that are
3382 // not yet in the vtable, because the vtable setup is in progress.
3383 // This must be done after we adjust the default_methods and
3384 // default_vtable_indices for methods already in the vtable.
3385 // If redefining Unsafe, walk all the vtables looking for entries.
3386 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
3387 || _the_class_oop == SystemDictionary::misc_Unsafe_klass()
3388 || ik->is_subtype_of(_the_class_oop))) {
3389 // ik->vtable() creates a wrapper object; rm cleans it up
3390 ResourceMark rm(_thread);
3391
3392 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3393 ik->adjust_default_methods(the_class, &trace_name_printed);
3394 }
3395
3396 // If the current class has an itable and we are either redefining an
3397 // interface or if the current class is a subclass of the_class, then
3398 // we potentially have to fix the itable. If we are redefining an
3399 // interface, then we have to call adjust_method_entries() for
3400 // every InstanceKlass that has an itable since there isn't a
3401 // subclass relationship between an interface and an InstanceKlass.
3402 // If redefining Unsafe, walk all the itables looking for entries.
3403 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
3404 || _the_class_oop == SystemDictionary::misc_Unsafe_klass()
3405 || ik->is_subclass_of(_the_class_oop))) {
3406 // ik->itable() creates a wrapper object; rm cleans it up
3407 ResourceMark rm(_thread);
3408
3409 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3410 }
3411
3412 // The constant pools in other classes (other_cp) can refer to
3413 // methods in the_class. We have to update method information in
3414 // other_cp's cache. If other_cp has a previous version, then we
3415 // have to repeat the process for each previous version. The
3416 // constant pool cache holds the Method*s for non-virtual
3417 // methods and for virtual, final methods.
3418 //
3419 // Special case: if the current class is the_class, then new_cp
3420 // has already been attached to the_class and old_cp has already
3421 // been added as a previous version. The new_cp doesn't have any
3422 // cached references to old methods so it doesn't need to be
3423 // updated. We can simply start with the previous version(s) in
3424 // that case.
3425 constantPoolHandle other_cp;
3426 ConstantPoolCache* cp_cache;
3427
3428 if (ik != _the_class_oop) {
3429 // this klass' constant pool cache may need adjustment
3430 other_cp = constantPoolHandle(ik->constants());
3431 cp_cache = other_cp->cache();
3432 if (cp_cache != NULL) {
3433 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3434 }
3435 }
3436
3437 // the previous versions' constant pool caches may need adjustment
3438 PreviousVersionWalker pvw(_thread, ik);
3439 for (PreviousVersionNode * pv_node = pvw.next_previous_version();
3440 pv_node != NULL; pv_node = pvw.next_previous_version()) {
3441 other_cp = pv_node->prev_constant_pool();
3442 cp_cache = other_cp->cache();
3443 if (cp_cache != NULL) {
3444 cp_cache->adjust_method_entries(other_cp->pool_holder(), &trace_name_printed);
3445 }
3446 }
3447 }
3448 }
3449
3450 void VM_RedefineClasses::update_jmethod_ids() {
3451 for (int j = 0; j < _matching_methods_length; ++j) {
3452 Method* old_method = _matching_old_methods[j];
3453 jmethodID jmid = old_method->find_jmethod_id_or_null();
3454 if (jmid != NULL) {
3455 // There is a jmethodID, change it to point to the new method
3456 methodHandle new_method_h(_matching_new_methods[j]);
3457 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3458 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3459 "should be replaced");
3460 }
3461 }
3462 }
3463
3464 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
3465 BitMap *emcp_methods, int * emcp_method_count_p) {
3466 *emcp_method_count_p = 0;
3467 int obsolete_count = 0;
3468 int old_index = 0;
3469 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3470 Method* old_method = _matching_old_methods[j];
3471 Method* new_method = _matching_new_methods[j];
3472 Method* old_array_method;
3473
3474 // Maintain an old_index into the _old_methods array by skipping
3475 // deleted methods
3476 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3477 ++old_index;
3478 }
3479
3480 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3481 // The EMCP definition from JSR-163 requires the bytecodes to be
3482 // the same with the exception of constant pool indices which may
3483 // differ. However, the constants referred to by those indices
3484 // must be the same.
3485 //
3486 // We use methods_EMCP() for comparison since constant pool
3487 // merging can remove duplicate constant pool entries that were
3488 // present in the old method and removed from the rewritten new
3489 // method. A faster binary comparison function would consider the
3490 // old and new methods to be different when they are actually
3491 // EMCP.
3492 //
3493 // The old and new methods are EMCP and you would think that we
3494 // could get rid of one of them here and now and save some space.
3495 // However, the concept of EMCP only considers the bytecodes and
3496 // the constant pool entries in the comparison. Other things,
3497 // e.g., the line number table (LNT) or the local variable table
3498 // (LVT) don't count in the comparison. So the new (and EMCP)
3499 // method can have a new LNT that we need so we can't just
3500 // overwrite the new method with the old method.
3501 //
3502 // When this routine is called, we have already attached the new
3503 // methods to the_class so the old methods are effectively
3504 // overwritten. However, if an old method is still executing,
3505 // then the old method cannot be collected until sometime after
3506 // the old method call has returned. So the overwriting of old
3507 // methods by new methods will save us space except for those
3508 // (hopefully few) old methods that are still executing.
3509 //
3510 // A method refers to a ConstMethod* and this presents another
3511 // possible avenue to space savings. The ConstMethod* in the
3512 // new method contains possibly new attributes (LNT, LVT, etc).
3513 // At first glance, it seems possible to save space by replacing
3514 // the ConstMethod* in the old method with the ConstMethod*
3515 // from the new method. The old and new methods would share the
3516 // same ConstMethod* and we would save the space occupied by
3517 // the old ConstMethod*. However, the ConstMethod* contains
3518 // a back reference to the containing method. Sharing the
3519 // ConstMethod* between two methods could lead to confusion in
3520 // the code that uses the back reference. This would lead to
3521 // brittle code that could be broken in non-obvious ways now or
3522 // in the future.
3523 //
3524 // Another possibility is to copy the ConstMethod* from the new
3525 // method to the old method and then overwrite the new method with
3526 // the old method. Since the ConstMethod* contains the bytecodes
3527 // for the method embedded in the oop, this option would change
3528 // the bytecodes out from under any threads executing the old
3529 // method and make the thread's bcp invalid. Since EMCP requires
3530 // that the bytecodes be the same modulo constant pool indices, it
3531 // is straight forward to compute the correct new bcp in the new
3532 // ConstMethod* from the old bcp in the old ConstMethod*. The
3533 // time consuming part would be searching all the frames in all
3534 // of the threads to find all of the calls to the old method.
3535 //
3536 // It looks like we will have to live with the limited savings
3537 // that we get from effectively overwriting the old methods
3538 // when the new methods are attached to the_class.
3539
3540 // track which methods are EMCP for add_previous_version() call
3541 emcp_methods->set_bit(old_index);
3542 (*emcp_method_count_p)++;
3543
3544 // An EMCP method is _not_ obsolete. An obsolete method has a
3545 // different jmethodID than the current method. An EMCP method
3546 // has the same jmethodID as the current method. Having the
3547 // same jmethodID for all EMCP versions of a method allows for
3548 // a consistent view of the EMCP methods regardless of which
3549 // EMCP method you happen to have in hand. For example, a
3550 // breakpoint set in one EMCP method will work for all EMCP
3551 // versions of the method including the current one.
3552 } else {
3553 // mark obsolete methods as such
3554 old_method->set_is_obsolete();
3555 obsolete_count++;
3556
3557 // obsolete methods need a unique idnum so they become new entries in
3558 // the jmethodID cache in InstanceKlass
3559 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3560 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
3561 if (num != ConstMethod::UNSET_IDNUM) {
3562 old_method->set_method_idnum(num);
3563 }
3564
3565 // With tracing we try not to "yack" too much. The position of
3566 // this trace assumes there are fewer obsolete methods than
3567 // EMCP methods.
3568 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
3569 old_method->name()->as_C_string(),
3570 old_method->signature()->as_C_string()));
3571 }
3572 old_method->set_is_old();
3573 }
3574 for (int i = 0; i < _deleted_methods_length; ++i) {
3575 Method* old_method = _deleted_methods[i];
3576
3577 assert(!old_method->has_vtable_index(),
3578 "cannot delete methods with vtable entries");;
3579
3580 // Mark all deleted methods as old, obsolete and deleted
3581 old_method->set_is_deleted();
3582 old_method->set_is_old();
3583 old_method->set_is_obsolete();
3584 ++obsolete_count;
3585 // With tracing we try not to "yack" too much. The position of
3586 // this trace assumes there are fewer obsolete methods than
3587 // EMCP methods.
3588 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
3589 old_method->name()->as_C_string(),
3590 old_method->signature()->as_C_string()));
3591 }
3592 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
3593 "sanity check");
3594 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
3595 obsolete_count));
3596 }
3597
3598 // This internal class transfers the native function registration from old methods
3599 // to new methods. It is designed to handle both the simple case of unchanged
3600 // native methods and the complex cases of native method prefixes being added and/or
3601 // removed.
3602 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3603 //
3604 // This class is used after the new methods have been installed in "the_class".
3605 //
3606 // So, for example, the following must be handled. Where 'm' is a method and
3607 // a number followed by an underscore is a prefix.
3608 //
3609 // Old Name New Name
3610 // Simple transfer to new method m -> m
3611 // Add prefix m -> 1_m
3612 // Remove prefix 1_m -> m
3613 // Simultaneous add of prefixes m -> 3_2_1_m
3614 // Simultaneous removal of prefixes 3_2_1_m -> m
3615 // Simultaneous add and remove 1_m -> 2_m
3616 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3617 //
3618 class TransferNativeFunctionRegistration {
3619 private:
3620 instanceKlassHandle the_class;
3621 int prefix_count;
3622 char** prefixes;
3623
3624 // Recursively search the binary tree of possibly prefixed method names.
3625 // Iteration could be used if all agents were well behaved. Full tree walk is
3626 // more resilent to agents not cleaning up intermediate methods.
3627 // Branch at each depth in the binary tree is:
3628 // (1) without the prefix.
3629 // (2) with the prefix.
3630 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3631 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3632 Symbol* signature) {
3633 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3634 if (name_symbol != NULL) {
3635 Method* method = the_class()->lookup_method(name_symbol, signature);
3636 if (method != NULL) {
3637 // Even if prefixed, intermediate methods must exist.
3638 if (method->is_native()) {
3639 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3640 return method;
3641 }
3642 if (depth < prefix_count) {
3643 // Try applying further prefixes (other than this one).
3644 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3645 if (method != NULL) {
3646 return method; // found
3647 }
3648
3649 // Try adding this prefix to the method name and see if it matches
3650 // another method name.
3651 char* prefix = prefixes[depth];
3652 size_t prefix_len = strlen(prefix);
3653 size_t trial_len = name_len + prefix_len;
3654 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3655 strcpy(trial_name_str, prefix);
3656 strcat(trial_name_str, name_str);
3657 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3658 signature);
3659 if (method != NULL) {
3660 // If found along this branch, it was prefixed, mark as such
3661 method->set_is_prefixed_native();
3662 return method; // found
3663 }
3664 }
3665 }
3666 }
3667 return NULL; // This whole branch bore nothing
3668 }
3669
3670 // Return the method name with old prefixes stripped away.
3671 char* method_name_without_prefixes(Method* method) {
3672 Symbol* name = method->name();
3673 char* name_str = name->as_utf8();
3674
3675 // Old prefixing may be defunct, strip prefixes, if any.
3676 for (int i = prefix_count-1; i >= 0; i--) {
3677 char* prefix = prefixes[i];
3678 size_t prefix_len = strlen(prefix);
3679 if (strncmp(prefix, name_str, prefix_len) == 0) {
3680 name_str += prefix_len;
3681 }
3682 }
3683 return name_str;
3684 }
3685
3686 // Strip any prefixes off the old native method, then try to find a
3687 // (possibly prefixed) new native that matches it.
3688 Method* strip_and_search_for_new_native(Method* method) {
3689 ResourceMark rm;
3690 char* name_str = method_name_without_prefixes(method);
3691 return search_prefix_name_space(0, name_str, strlen(name_str),
3692 method->signature());
3693 }
3694
3695 public:
3696
3697 // Construct a native method transfer processor for this class.
3698 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3699 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3700
3701 the_class = _the_class;
3702 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3703 }
3704
3705 // Attempt to transfer any of the old or deleted methods that are native
3706 void transfer_registrations(Method** old_methods, int methods_length) {
3707 for (int j = 0; j < methods_length; j++) {
3708 Method* old_method = old_methods[j];
3709
3710 if (old_method->is_native() && old_method->has_native_function()) {
3711 Method* new_method = strip_and_search_for_new_native(old_method);
3712 if (new_method != NULL) {
3713 // Actually set the native function in the new method.
3714 // Redefine does not send events (except CFLH), certainly not this
3715 // behind the scenes re-registration.
3716 new_method->set_native_function(old_method->native_function(),
3717 !Method::native_bind_event_is_interesting);
3718 }
3719 }
3720 }
3721 }
3722 };
3723
3724 // Don't lose the association between a native method and its JNI function.
3725 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3726 TransferNativeFunctionRegistration transfer(the_class);
3727 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3728 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3729 }
3730
3731 // Deoptimize all compiled code that depends on this class.
3732 //
3733 // If the can_redefine_classes capability is obtained in the onload
3734 // phase then the compiler has recorded all dependencies from startup.
3735 // In that case we need only deoptimize and throw away all compiled code
3736 // that depends on the class.
3737 //
3738 // If can_redefine_classes is obtained sometime after the onload
3739 // phase then the dependency information may be incomplete. In that case
3740 // the first call to RedefineClasses causes all compiled code to be
3741 // thrown away. As can_redefine_classes has been obtained then
3742 // all future compilations will record dependencies so second and
3743 // subsequent calls to RedefineClasses need only throw away code
3744 // that depends on the class.
3745 //
3746 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3747 assert_locked_or_safepoint(Compile_lock);
3748
3749 // All dependencies have been recorded from startup or this is a second or
3750 // subsequent use of RedefineClasses
3751 if (JvmtiExport::all_dependencies_are_recorded()) {
3752 Universe::flush_evol_dependents_on(k_h);
3753 } else {
3754 CodeCache::mark_all_nmethods_for_deoptimization();
3755
3756 ResourceMark rm(THREAD);
3757 DeoptimizationMarker dm;
3758
3759 // Deoptimize all activations depending on marked nmethods
3760 Deoptimization::deoptimize_dependents();
3761
3762 // Make the dependent methods not entrant
3763 CodeCache::make_marked_nmethods_not_entrant();
3764
3765 // From now on we know that the dependency information is complete
3766 JvmtiExport::set_all_dependencies_are_recorded(true);
3767 }
3768 }
3769
3770 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3771 Method* old_method;
3772 Method* new_method;
3773
3774 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3775 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3776 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3777 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3778
3779 _matching_methods_length = 0;
3780 _deleted_methods_length = 0;
3781 _added_methods_length = 0;
3782
3783 int nj = 0;
3784 int oj = 0;
3785 while (true) {
3786 if (oj >= _old_methods->length()) {
3787 if (nj >= _new_methods->length()) {
3788 break; // we've looked at everything, done
3789 }
3790 // New method at the end
3791 new_method = _new_methods->at(nj);
3792 _added_methods[_added_methods_length++] = new_method;
3793 ++nj;
3794 } else if (nj >= _new_methods->length()) {
3795 // Old method, at the end, is deleted
3796 old_method = _old_methods->at(oj);
3797 _deleted_methods[_deleted_methods_length++] = old_method;
3798 ++oj;
3799 } else {
3800 old_method = _old_methods->at(oj);
3801 new_method = _new_methods->at(nj);
3802 if (old_method->name() == new_method->name()) {
3803 if (old_method->signature() == new_method->signature()) {
3804 _matching_old_methods[_matching_methods_length ] = old_method;
3805 _matching_new_methods[_matching_methods_length++] = new_method;
3806 ++nj;
3807 ++oj;
3808 } else {
3809 // added overloaded have already been moved to the end,
3810 // so this is a deleted overloaded method
3811 _deleted_methods[_deleted_methods_length++] = old_method;
3812 ++oj;
3813 }
3814 } else { // names don't match
3815 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3816 // new method
3817 _added_methods[_added_methods_length++] = new_method;
3818 ++nj;
3819 } else {
3820 // deleted method
3821 _deleted_methods[_deleted_methods_length++] = old_method;
3822 ++oj;
3823 }
3824 }
3825 }
3826 }
3827 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3828 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3829 }
3830
3831
3832 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3833 instanceKlassHandle scratch_class) {
3834 // Swap annotation fields values
3835 Annotations* old_annotations = the_class->annotations();
3836 the_class->set_annotations(scratch_class->annotations());
3837 scratch_class->set_annotations(old_annotations);
3838 }
3839
3840
3841 // Install the redefinition of a class:
3842 // - house keeping (flushing breakpoints and caches, deoptimizing
3843 // dependent compiled code)
3844 // - replacing parts in the_class with parts from scratch_class
3845 // - adding a weak reference to track the obsolete but interesting
3846 // parts of the_class
3847 // - adjusting constant pool caches and vtables in other classes
3848 // that refer to methods in the_class. These adjustments use the
3849 // ClassLoaderDataGraph::classes_do() facility which only allows
3850 // a helper method to be specified. The interesting parameters
3851 // that we would like to pass to the helper method are saved in
3852 // static global fields in the VM operation.
3853 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3854 Klass* scratch_class_oop, TRAPS) {
3855
3856 HandleMark hm(THREAD); // make sure handles from this call are freed
3857 RC_TIMER_START(_timer_rsc_phase1);
3858
3859 instanceKlassHandle scratch_class(scratch_class_oop);
3860
3861 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3862 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3863 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3864
3865 // Remove all breakpoints in methods of this class
3866 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3867 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3868
3869 // Deoptimize all compiled code that depends on this class
3870 flush_dependent_code(the_class, THREAD);
3871
3872 _old_methods = the_class->methods();
3873 _new_methods = scratch_class->methods();
3874 _the_class_oop = the_class_oop;
3875 compute_added_deleted_matching_methods();
3876 update_jmethod_ids();
3877
3878 // Attach new constant pool to the original klass. The original
3879 // klass still refers to the old constant pool (for now).
3880 scratch_class->constants()->set_pool_holder(the_class());
3881
3882 #if 0
3883 // In theory, with constant pool merging in place we should be able
3884 // to save space by using the new, merged constant pool in place of
3885 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3886 // the klass version we are replacing now and any constant pool(s) in
3887 // previous versions of klass. Nice theory, doesn't work in practice.
3888 // When this code is enabled, even simple programs throw NullPointer
3889 // exceptions. I'm guessing that this is caused by some constant pool
3890 // cache difference between the new, merged constant pool and the
3891 // constant pool that was just being used by the klass. I'm keeping
3892 // this code around to archive the idea, but the code has to remain
3893 // disabled for now.
3894
3895 // Attach each old method to the new constant pool. This can be
3896 // done here since we are past the bytecode verification and
3897 // constant pool optimization phases.
3898 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3899 Method* method = _old_methods->at(i);
3900 method->set_constants(scratch_class->constants());
3901 }
3902
3903 {
3904 // walk all previous versions of the klass
3905 InstanceKlass *ik = (InstanceKlass *)the_class();
3906 PreviousVersionWalker pvw(ik);
3907 instanceKlassHandle ikh;
3908 do {
3909 ikh = pvw.next_previous_version();
3910 if (!ikh.is_null()) {
3911 ik = ikh();
3912
3913 // attach previous version of klass to the new constant pool
3914 ik->set_constants(scratch_class->constants());
3915
3916 // Attach each method in the previous version of klass to the
3917 // new constant pool
3918 Array<Method*>* prev_methods = ik->methods();
3919 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3920 Method* method = prev_methods->at(i);
3921 method->set_constants(scratch_class->constants());
3922 }
3923 }
3924 } while (!ikh.is_null());
3925 }
3926 #endif
3927
3928 // Replace methods and constantpool
3929 the_class->set_methods(_new_methods);
3930 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3931 // and to be able to undo operation easily.
3932
3933 Array<int>* old_ordering = the_class->method_ordering();
3934 the_class->set_method_ordering(scratch_class->method_ordering());
3935 scratch_class->set_method_ordering(old_ordering);
3936
3937 ConstantPool* old_constants = the_class->constants();
3938 the_class->set_constants(scratch_class->constants());
3939 scratch_class->set_constants(old_constants); // See the previous comment.
3940 #if 0
3941 // We are swapping the guts of "the new class" with the guts of "the
3942 // class". Since the old constant pool has just been attached to "the
3943 // new class", it seems logical to set the pool holder in the old
3944 // constant pool also. However, doing this will change the observable
3945 // class hierarchy for any old methods that are still executing. A
3946 // method can query the identity of its "holder" and this query uses
3947 // the method's constant pool link to find the holder. The change in
3948 // holding class from "the class" to "the new class" can confuse
3949 // things.
3950 //
3951 // Setting the old constant pool's holder will also cause
3952 // verification done during vtable initialization below to fail.
3953 // During vtable initialization, the vtable's class is verified to be
3954 // a subtype of the method's holder. The vtable's class is "the
3955 // class" and the method's holder is gotten from the constant pool
3956 // link in the method itself. For "the class"'s directly implemented
3957 // methods, the method holder is "the class" itself (as gotten from
3958 // the new constant pool). The check works fine in this case. The
3959 // check also works fine for methods inherited from super classes.
3960 //
3961 // Miranda methods are a little more complicated. A miranda method is
3962 // provided by an interface when the class implementing the interface
3963 // does not provide its own method. These interfaces are implemented
3964 // internally as an InstanceKlass. These special instanceKlasses
3965 // share the constant pool of the class that "implements" the
3966 // interface. By sharing the constant pool, the method holder of a
3967 // miranda method is the class that "implements" the interface. In a
3968 // non-redefine situation, the subtype check works fine. However, if
3969 // the old constant pool's pool holder is modified, then the check
3970 // fails because there is no class hierarchy relationship between the
3971 // vtable's class and "the new class".
3972
3973 old_constants->set_pool_holder(scratch_class());
3974 #endif
3975
3976 // track which methods are EMCP for add_previous_version() call below
3977 BitMap emcp_methods(_old_methods->length());
3978 int emcp_method_count = 0;
3979 emcp_methods.clear(); // clears 0..(length() - 1)
3980 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3981 transfer_old_native_function_registrations(the_class);
3982
3983 // The class file bytes from before any retransformable agents mucked
3984 // with them was cached on the scratch class, move to the_class.
3985 // Note: we still want to do this if nothing needed caching since it
3986 // should get cleared in the_class too.
3987 if (the_class->get_cached_class_file_bytes() == 0) {
3988 // the_class doesn't have a cache yet so copy it
3989 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3990 }
3991 else if (scratch_class->get_cached_class_file_bytes() !=
3992 the_class->get_cached_class_file_bytes()) {
3993 // The same class can be present twice in the scratch classes list or there
3994 // are multiple concurrent RetransformClasses calls on different threads.
3995 // In such cases we have to deallocate scratch_class cached_class_file.
3996 os::free(scratch_class->get_cached_class_file());
3997 }
3998
3999 // NULL out in scratch class to not delete twice. The class to be redefined
4000 // always owns these bytes.
4001 scratch_class->set_cached_class_file(NULL);
4002
4003 // Replace inner_classes
4004 Array<u2>* old_inner_classes = the_class->inner_classes();
4005 the_class->set_inner_classes(scratch_class->inner_classes());
4006 scratch_class->set_inner_classes(old_inner_classes);
4007
4008 // Initialize the vtable and interface table after
4009 // methods have been rewritten
4010 {
4011 ResourceMark rm(THREAD);
4012 // no exception should happen here since we explicitly
4013 // do not check loader constraints.
4014 // compare_and_normalize_class_versions has already checked:
4015 // - classloaders unchanged, signatures unchanged
4016 // - all instanceKlasses for redefined classes reused & contents updated
4017 the_class->vtable()->initialize_vtable(false, THREAD);
4018 the_class->itable()->initialize_itable(false, THREAD);
4019 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4020 }
4021
4022 // Leave arrays of jmethodIDs and itable index cache unchanged
4023
4024 // Copy the "source file name" attribute from new class version
4025 the_class->set_source_file_name_index(
4026 scratch_class->source_file_name_index());
4027
4028 // Copy the "source debug extension" attribute from new class version
4029 the_class->set_source_debug_extension(
4030 scratch_class->source_debug_extension(),
4031 scratch_class->source_debug_extension() == NULL ? 0 :
4032 (int)strlen(scratch_class->source_debug_extension()));
4033
4034 // Use of javac -g could be different in the old and the new
4035 if (scratch_class->access_flags().has_localvariable_table() !=
4036 the_class->access_flags().has_localvariable_table()) {
4037
4038 AccessFlags flags = the_class->access_flags();
4039 if (scratch_class->access_flags().has_localvariable_table()) {
4040 flags.set_has_localvariable_table();
4041 } else {
4042 flags.clear_has_localvariable_table();
4043 }
4044 the_class->set_access_flags(flags);
4045 }
4046
4047 swap_annotations(the_class, scratch_class);
4048
4049 // Replace minor version number of class file
4050 u2 old_minor_version = the_class->minor_version();
4051 the_class->set_minor_version(scratch_class->minor_version());
4052 scratch_class->set_minor_version(old_minor_version);
4053
4054 // Replace major version number of class file
4055 u2 old_major_version = the_class->major_version();
4056 the_class->set_major_version(scratch_class->major_version());
4057 scratch_class->set_major_version(old_major_version);
4058
4059 // Replace CP indexes for class and name+type of enclosing method
4060 u2 old_class_idx = the_class->enclosing_method_class_index();
4061 u2 old_method_idx = the_class->enclosing_method_method_index();
4062 the_class->set_enclosing_method_indices(
4063 scratch_class->enclosing_method_class_index(),
4064 scratch_class->enclosing_method_method_index());
4065 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4066
4067 // keep track of previous versions of this class
4068 the_class->add_previous_version(scratch_class, &emcp_methods,
4069 emcp_method_count);
4070
4071 RC_TIMER_STOP(_timer_rsc_phase1);
4072 RC_TIMER_START(_timer_rsc_phase2);
4073
4074 // Adjust constantpool caches and vtables for all classes
4075 // that reference methods of the evolved class.
4076 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4077 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4078
4079 // JSR-292 support
4080 MemberNameTable* mnt = the_class->member_names();
4081 if (mnt != NULL) {
4082 bool trace_name_printed = false;
4083 mnt->adjust_method_entries(the_class(), &trace_name_printed);
4084 }
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 {
4104 ResourceMark rm(THREAD);
4105 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4106 the_class->external_name(),
4107 java_lang_Class::classRedefinedCount(the_class_mirror));
4108
4109 }
4110 RC_TIMER_STOP(_timer_rsc_phase2);
4111 } // end redefine_single_class()
4112
4113
4114 // Increment the classRedefinedCount field in the specific InstanceKlass
4115 // and in all direct and indirect subclasses.
4116 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4117 oop class_mirror = ik->java_mirror();
4118 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4119 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4120 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4121
4122 if (class_oop != _the_class_oop) {
4123 // _the_class_oop count is printed at end of redefine_single_class()
4124 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
4125 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
4126 }
4127
4128 for (Klass *subk = ik->subklass(); subk != NULL;
4129 subk = subk->next_sibling()) {
4130 if (subk->oop_is_instance()) {
4131 // Only update instanceKlasses
4132 InstanceKlass *subik = (InstanceKlass*)subk;
4133 // recursively do subclasses of the current subclass
4134 increment_class_counter(subik, THREAD);
4135 }
4136 }
4137 }
4138
4139 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4140 bool no_old_methods = true; // be optimistic
4141
4142 // Both array and instance classes have vtables.
4143 // a vtable should never contain old or obsolete methods
4144 ResourceMark rm(_thread);
4145 if (k->vtable_length() > 0 &&
4146 !k->vtable()->check_no_old_or_obsolete_entries()) {
4147 if (RC_TRACE_ENABLED(0x00004000)) {
4148 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4149 ("klassVtable::check_no_old_or_obsolete_entries failure"
4150 " -- OLD or OBSOLETE method found -- class: %s",
4151 k->signature_name()));
4152 k->vtable()->dump_vtable();
4153 }
4154 no_old_methods = false;
4155 }
4156
4157 if (k->oop_is_instance()) {
4158 HandleMark hm(_thread);
4159 InstanceKlass *ik = InstanceKlass::cast(k);
4160
4161 // an itable should never contain old or obsolete methods
4162 if (ik->itable_length() > 0 &&
4163 !ik->itable()->check_no_old_or_obsolete_entries()) {
4164 if (RC_TRACE_ENABLED(0x00004000)) {
4165 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4166 ("klassItable::check_no_old_or_obsolete_entries failure"
4167 " -- OLD or OBSOLETE method found -- class: %s",
4168 ik->signature_name()));
4169 ik->itable()->dump_itable();
4170 }
4171 no_old_methods = false;
4172 }
4173
4174 // the constant pool cache should never contain non-deleted old or obsolete methods
4175 if (ik->constants() != NULL &&
4176 ik->constants()->cache() != NULL &&
4177 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4178 if (RC_TRACE_ENABLED(0x00004000)) {
4179 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4180 ("cp-cache::check_no_old_or_obsolete_entries failure"
4181 " -- OLD or OBSOLETE method found -- class: %s",
4182 ik->signature_name()));
4183 ik->constants()->cache()->dump_cache();
4184 }
4185 no_old_methods = false;
4186 }
4187 }
4188
4189 // print and fail guarantee if old methods are found.
4190 if (!no_old_methods) {
4191 if (RC_TRACE_ENABLED(0x00004000)) {
4192 dump_methods();
4193 } else {
4194 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
4195 "to see more info about the following guarantee() failure.");
4196 }
4197 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4198 }
4199 }
4200
4201
4202 void VM_RedefineClasses::dump_methods() {
4203 int j;
4204 RC_TRACE(0x00004000, ("_old_methods --"));
4205 for (j = 0; j < _old_methods->length(); ++j) {
4206 Method* m = _old_methods->at(j);
4207 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4208 m->access_flags().print_on(tty);
4209 tty->print(" -- ");
4210 m->print_name(tty);
4211 tty->cr();
4212 }
4213 RC_TRACE(0x00004000, ("_new_methods --"));
4214 for (j = 0; j < _new_methods->length(); ++j) {
4215 Method* m = _new_methods->at(j);
4216 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4217 m->access_flags().print_on(tty);
4218 tty->print(" -- ");
4219 m->print_name(tty);
4220 tty->cr();
4221 }
4222 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
4223 for (j = 0; j < _matching_methods_length; ++j) {
4224 Method* m = _matching_old_methods[j];
4225 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4226 m->access_flags().print_on(tty);
4227 tty->print(" -- ");
4228 m->print_name(tty);
4229 tty->cr();
4230 m = _matching_new_methods[j];
4231 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
4232 m->access_flags().print_on(tty);
4233 tty->cr();
4234 }
4235 RC_TRACE(0x00004000, ("_deleted_methods --"));
4236 for (j = 0; j < _deleted_methods_length; ++j) {
4237 Method* m = _deleted_methods[j];
4238 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4239 m->access_flags().print_on(tty);
4240 tty->print(" -- ");
4241 m->print_name(tty);
4242 tty->cr();
4243 }
4244 RC_TRACE(0x00004000, ("_added_methods --"));
4245 for (j = 0; j < _added_methods_length; ++j) {
4246 Method* m = _added_methods[j];
4247 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4248 m->access_flags().print_on(tty);
4249 tty->print(" -- ");
4250 m->print_name(tty);
4251 tty->cr();
4252 }
4253 }
4254
4255 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4256 VM_Operation::print_on_error(st);
4257 if (_the_class_oop != NULL) {
4258 ResourceMark rm;
4259 st->print_cr(", redefining class %s", _the_class_oop->external_name());
4260 }
4261 }