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