1 /*
2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/metadataOnStackMark.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "interpreter/oopMapCache.hpp"
32 #include "interpreter/rewriter.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/klassVtable.hpp"
39 #include "prims/jvmtiImpl.hpp"
40 #include "prims/jvmtiRedefineClasses.hpp"
41 #include "prims/methodComparator.hpp"
42 #include "runtime/deoptimization.hpp"
43 #include "runtime/relocator.hpp"
44 #include "utilities/bitMap.inline.hpp"
45
46
47 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
48 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
49 Method** VM_RedefineClasses::_matching_old_methods = NULL;
50 Method** VM_RedefineClasses::_matching_new_methods = NULL;
51 Method** VM_RedefineClasses::_deleted_methods = NULL;
52 Method** VM_RedefineClasses::_added_methods = NULL;
53 int VM_RedefineClasses::_matching_methods_length = 0;
54 int VM_RedefineClasses::_deleted_methods_length = 0;
55 int VM_RedefineClasses::_added_methods_length = 0;
56 Klass* VM_RedefineClasses::_the_class_oop = NULL;
57
58
59 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
60 const jvmtiClassDefinition *class_defs,
61 JvmtiClassLoadKind class_load_kind) {
62 _class_count = class_count;
63 _class_defs = class_defs;
64 _class_load_kind = class_load_kind;
65 _res = JVMTI_ERROR_NONE;
66 }
67
68 bool VM_RedefineClasses::doit_prologue() {
69 if (_class_count == 0) {
70 _res = JVMTI_ERROR_NONE;
71 return false;
72 }
73 if (_class_defs == NULL) {
74 _res = JVMTI_ERROR_NULL_POINTER;
75 return false;
76 }
77 for (int i = 0; i < _class_count; i++) {
78 if (_class_defs[i].klass == NULL) {
79 _res = JVMTI_ERROR_INVALID_CLASS;
80 return false;
81 }
82 if (_class_defs[i].class_byte_count == 0) {
83 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
84 return false;
85 }
86 if (_class_defs[i].class_bytes == NULL) {
87 _res = JVMTI_ERROR_NULL_POINTER;
88 return false;
89 }
90 }
91
92 // Start timer after all the sanity checks; not quite accurate, but
93 // better than adding a bunch of stop() calls.
94 RC_TIMER_START(_timer_vm_op_prologue);
95
96 // We first load new class versions in the prologue, because somewhere down the
97 // call chain it is required that the current thread is a Java thread.
98 _res = load_new_class_versions(Thread::current());
99 if (_res != JVMTI_ERROR_NONE) {
100 // free any successfully created classes, since none are redefined
101 for (int i = 0; i < _class_count; i++) {
102 if (_scratch_classes[i] != NULL) {
103 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
104 // Free the memory for this class at class unloading time. Not before
105 // because CMS might think this is still live.
106 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
107 }
108 }
109 // Free os::malloc allocated memory in load_new_class_version.
110 os::free(_scratch_classes);
111 RC_TIMER_STOP(_timer_vm_op_prologue);
112 return false;
113 }
114
115 RC_TIMER_STOP(_timer_vm_op_prologue);
116 return true;
117 }
118
119 void VM_RedefineClasses::doit() {
120 Thread *thread = Thread::current();
121
122 if (UseSharedSpaces) {
123 // Sharing is enabled so we remap the shared readonly space to
124 // shared readwrite, private just in case we need to redefine
125 // a shared class. We do the remap during the doit() phase of
126 // the safepoint to be safer.
127 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
128 RC_TRACE_WITH_THREAD(0x00000001, thread,
129 ("failed to remap shared readonly space to readwrite, private"));
130 _res = JVMTI_ERROR_INTERNAL;
131 return;
132 }
133 }
134
135 // Mark methods seen on stack and everywhere else so old methods are not
136 // cleaned up if they're on the stack.
137 MetadataOnStackMark md_on_stack;
138 HandleMark hm(thread); // make sure any handles created are deleted
139 // before the stack walk again.
140
141 for (int i = 0; i < _class_count; i++) {
142 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
143 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
144 // Free the memory for this class at class unloading time. Not before
145 // because CMS might think this is still live.
146 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
147 _scratch_classes[i] = NULL;
148 }
149
150 // Disable any dependent concurrent compilations
151 SystemDictionary::notice_modification();
152
153 // Set flag indicating that some invariants are no longer true.
154 // See jvmtiExport.hpp for detailed explanation.
155 JvmtiExport::set_has_redefined_a_class();
156
157 // check_class() is optionally called for product bits, but is
158 // always called for non-product bits.
159 #ifdef PRODUCT
160 if (RC_TRACE_ENABLED(0x00004000)) {
161 #endif
162 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
163 CheckClass check_class(thread);
164 ClassLoaderDataGraph::classes_do(&check_class);
165 #ifdef PRODUCT
166 }
167 #endif
168 }
169
170 void VM_RedefineClasses::doit_epilogue() {
171 // Free os::malloc allocated memory.
172 os::free(_scratch_classes);
173
174 if (RC_TRACE_ENABLED(0x00000004)) {
175 // Used to have separate timers for "doit" and "all", but the timer
176 // overhead skewed the measurements.
177 jlong doit_time = _timer_rsc_phase1.milliseconds() +
178 _timer_rsc_phase2.milliseconds();
179 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
180
181 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
182 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
183 _timer_vm_op_prologue.milliseconds(), doit_time));
184 RC_TRACE(0x00000004,
185 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
186 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
187 }
188 }
189
190 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
191 // classes for primitives cannot be redefined
192 if (java_lang_Class::is_primitive(klass_mirror)) {
193 return false;
194 }
195 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
196 // classes for arrays cannot be redefined
197 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
198 return false;
199 }
200 return true;
201 }
202
203 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
204 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
205 // direct CP entries, there is just the current entry to append. For
206 // indirect and double-indirect CP entries, there are zero or more
207 // referenced CP entries along with the current entry to append.
208 // Indirect and double-indirect CP entries are handled by recursive
209 // calls to append_entry() as needed. The referenced CP entries are
210 // always appended to *merge_cp_p before the referee CP entry. These
211 // referenced CP entries may already exist in *merge_cp_p in which case
212 // there is nothing extra to append and only the current entry is
213 // appended.
214 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
215 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
216 TRAPS) {
217
218 // append is different depending on entry tag type
219 switch (scratch_cp->tag_at(scratch_i).value()) {
220
221 // The old verifier is implemented outside the VM. It loads classes,
222 // but does not resolve constant pool entries directly so we never
223 // see Class entries here with the old verifier. Similarly the old
224 // verifier does not like Class entries in the input constant pool.
225 // The split-verifier is implemented in the VM so it can optionally
226 // and directly resolve constant pool entries to load classes. The
227 // split-verifier can accept either Class entries or UnresolvedClass
228 // entries in the input constant pool. We revert the appended copy
229 // back to UnresolvedClass so that either verifier will be happy
230 // with the constant pool entry.
231 case JVM_CONSTANT_Class:
232 {
233 // revert the copy to JVM_CONSTANT_UnresolvedClass
234 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
235 scratch_cp->klass_name_at(scratch_i));
236
237 if (scratch_i != *merge_cp_length_p) {
238 // The new entry in *merge_cp_p is at a different index than
239 // the new entry in scratch_cp so we need to map the index values.
240 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
241 }
242 (*merge_cp_length_p)++;
243 } break;
244
245 // these are direct CP entries so they can be directly appended,
246 // but double and long take two constant pool entries
247 case JVM_CONSTANT_Double: // fall through
248 case JVM_CONSTANT_Long:
249 {
250 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
251 THREAD);
252
253 if (scratch_i != *merge_cp_length_p) {
254 // The new entry in *merge_cp_p is at a different index than
255 // the new entry in scratch_cp so we need to map the index values.
256 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
257 }
258 (*merge_cp_length_p) += 2;
259 } break;
260
261 // these are direct CP entries so they can be directly appended
262 case JVM_CONSTANT_Float: // fall through
263 case JVM_CONSTANT_Integer: // fall through
264 case JVM_CONSTANT_Utf8: // fall through
265
266 // This was an indirect CP entry, but it has been changed into
267 // Symbol*s so this entry can be directly appended.
268 case JVM_CONSTANT_String: // fall through
269
270 // These were indirect CP entries, but they have been changed into
271 // Symbol*s so these entries can be directly appended.
272 case JVM_CONSTANT_UnresolvedClass: // fall through
273 {
274 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
275 THREAD);
276
277 if (scratch_i != *merge_cp_length_p) {
278 // The new entry in *merge_cp_p is at a different index than
279 // the new entry in scratch_cp so we need to map the index values.
280 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
281 }
282 (*merge_cp_length_p)++;
283 } break;
284
285 // this is an indirect CP entry so it needs special handling
286 case JVM_CONSTANT_NameAndType:
287 {
288 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
289 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
290 merge_cp_length_p, THREAD);
291
292 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
293 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
294 merge_cp_p, merge_cp_length_p,
295 THREAD);
296
297 // If the referenced entries already exist in *merge_cp_p, then
298 // both new_name_ref_i and new_signature_ref_i will both be 0.
299 // In that case, all we are appending is the current entry.
300 if (new_name_ref_i != name_ref_i) {
301 RC_TRACE(0x00080000,
302 ("NameAndType entry@%d name_ref_index change: %d to %d",
303 *merge_cp_length_p, name_ref_i, new_name_ref_i));
304 }
305 if (new_signature_ref_i != signature_ref_i) {
306 RC_TRACE(0x00080000,
307 ("NameAndType entry@%d signature_ref_index change: %d to %d",
308 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
309 }
310
311 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
312 new_name_ref_i, new_signature_ref_i);
313 if (scratch_i != *merge_cp_length_p) {
314 // The new entry in *merge_cp_p is at a different index than
315 // the new entry in scratch_cp so we need to map the index values.
316 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
317 }
318 (*merge_cp_length_p)++;
319 } break;
320
321 // this is a double-indirect CP entry so it needs special handling
322 case JVM_CONSTANT_Fieldref: // fall through
323 case JVM_CONSTANT_InterfaceMethodref: // fall through
324 case JVM_CONSTANT_Methodref:
325 {
326 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
327 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
328 merge_cp_p, merge_cp_length_p, THREAD);
329
330 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
331 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
332 merge_cp_p, merge_cp_length_p, THREAD);
333
334 const char *entry_name;
335 switch (scratch_cp->tag_at(scratch_i).value()) {
336 case JVM_CONSTANT_Fieldref:
337 entry_name = "Fieldref";
338 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
339 new_name_and_type_ref_i);
340 break;
341 case JVM_CONSTANT_InterfaceMethodref:
342 entry_name = "IFMethodref";
343 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
344 new_klass_ref_i, new_name_and_type_ref_i);
345 break;
346 case JVM_CONSTANT_Methodref:
347 entry_name = "Methodref";
348 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
349 new_name_and_type_ref_i);
350 break;
351 default:
352 guarantee(false, "bad switch");
353 break;
354 }
355
356 if (klass_ref_i != new_klass_ref_i) {
357 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
358 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
359 }
360 if (name_and_type_ref_i != new_name_and_type_ref_i) {
361 RC_TRACE(0x00080000,
362 ("%s entry@%d name_and_type_index changed: %d to %d",
363 entry_name, *merge_cp_length_p, name_and_type_ref_i,
364 new_name_and_type_ref_i));
365 }
366
367 if (scratch_i != *merge_cp_length_p) {
368 // The new entry in *merge_cp_p is at a different index than
369 // the new entry in scratch_cp so we need to map the index values.
370 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
371 }
372 (*merge_cp_length_p)++;
373 } break;
374
375 // this is an indirect CP entry so it needs special handling
376 case JVM_CONSTANT_MethodType:
377 {
378 int ref_i = scratch_cp->method_type_index_at(scratch_i);
379 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
380 merge_cp_length_p, THREAD);
381 if (new_ref_i != ref_i) {
382 RC_TRACE(0x00080000,
383 ("MethodType entry@%d ref_index change: %d to %d",
384 *merge_cp_length_p, ref_i, new_ref_i));
385 }
386 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
387 if (scratch_i != *merge_cp_length_p) {
388 // The new entry in *merge_cp_p is at a different index than
389 // the new entry in scratch_cp so we need to map the index values.
390 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
391 }
392 (*merge_cp_length_p)++;
393 } break;
394
395 // this is an indirect CP entry so it needs special handling
396 case JVM_CONSTANT_MethodHandle:
397 {
398 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
399 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
400 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
401 merge_cp_length_p, THREAD);
402 if (new_ref_i != ref_i) {
403 RC_TRACE(0x00080000,
404 ("MethodHandle entry@%d ref_index change: %d to %d",
405 *merge_cp_length_p, ref_i, new_ref_i));
406 }
407 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
408 if (scratch_i != *merge_cp_length_p) {
409 // The new entry in *merge_cp_p is at a different index than
410 // the new entry in scratch_cp so we need to map the index values.
411 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
412 }
413 (*merge_cp_length_p)++;
414 } break;
415
416 // this is an indirect CP entry so it needs special handling
417 case JVM_CONSTANT_InvokeDynamic:
418 {
419 // Index of the bootstrap specifier in the operands array
420 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
421 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
422 merge_cp_length_p, THREAD);
423 // The bootstrap method NameAndType_info index
424 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
425 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
426 merge_cp_length_p, THREAD);
427 if (new_bs_i != old_bs_i) {
428 RC_TRACE(0x00080000,
429 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
430 *merge_cp_length_p, old_bs_i, new_bs_i));
431 }
432 if (new_ref_i != old_ref_i) {
433 RC_TRACE(0x00080000,
434 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
435 *merge_cp_length_p, old_ref_i, new_ref_i));
436 }
437
438 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
439 if (scratch_i != *merge_cp_length_p) {
440 // The new entry in *merge_cp_p is at a different index than
441 // the new entry in scratch_cp so we need to map the index values.
442 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
443 }
444 (*merge_cp_length_p)++;
445 } break;
446
447 // At this stage, Class or UnresolvedClass could be here, but not
448 // ClassIndex
449 case JVM_CONSTANT_ClassIndex: // fall through
450
451 // Invalid is used as the tag for the second constant pool entry
452 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
453 // not be seen by itself.
454 case JVM_CONSTANT_Invalid: // fall through
455
456 // At this stage, String could be here, but not StringIndex
457 case JVM_CONSTANT_StringIndex: // fall through
458
459 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
460 // here
461 case JVM_CONSTANT_UnresolvedClassInError: // fall through
462
463 default:
464 {
465 // leave a breadcrumb
466 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
467 ShouldNotReachHere();
468 } break;
469 } // end switch tag value
470 } // end append_entry()
471
472
473 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
474 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
475
476 int new_ref_i = ref_i;
477 bool match = (ref_i < *merge_cp_length_p) &&
478 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
479
480 if (!match) {
481 // forward reference in *merge_cp_p or not a direct match
482 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
483 if (found_i != 0) {
484 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
485 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
486 new_ref_i = found_i;
487 map_index(scratch_cp, ref_i, found_i);
488 } else {
489 // no match found so we have to append this entry to *merge_cp_p
490 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
491 // The above call to append_entry() can only append one entry
492 // so the post call query of *merge_cp_length_p is only for
493 // the sake of consistency.
494 new_ref_i = *merge_cp_length_p - 1;
495 }
496 }
497
498 return new_ref_i;
499 } // end find_or_append_indirect_entry()
500
501
502 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
503 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
504 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
505 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
506 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
507
508 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
509 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
510 merge_cp_length_p, THREAD);
511 if (new_ref_i != old_ref_i) {
512 RC_TRACE(0x00080000,
513 ("operands entry@%d bootstrap method ref_index change: %d to %d",
514 _operands_cur_length, old_ref_i, new_ref_i));
515 }
516
517 Array<u2>* merge_ops = (*merge_cp_p)->operands();
518 int new_bs_i = _operands_cur_length;
519 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
520 // However, the operand_offset_at(0) was set in the extend_operands() call.
521 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
522 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
523 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
524
525 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
526 merge_ops->at_put(new_base++, new_ref_i);
527 merge_ops->at_put(new_base++, argc);
528
529 for (int i = 0; i < argc; i++) {
530 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
531 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
532 merge_cp_length_p, THREAD);
533 merge_ops->at_put(new_base++, new_arg_ref_i);
534 if (new_arg_ref_i != old_arg_ref_i) {
535 RC_TRACE(0x00080000,
536 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
537 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
538 }
539 }
540 if (old_bs_i != _operands_cur_length) {
541 // The bootstrap specifier in *merge_cp_p is at a different index than
542 // that in scratch_cp so we need to map the index values.
543 map_operand_index(old_bs_i, new_bs_i);
544 }
545 _operands_cur_length++;
546 } // end append_operand()
547
548
549 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
550 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
551
552 int new_bs_i = old_bs_i; // bootstrap specifier index
553 bool match = (old_bs_i < _operands_cur_length) &&
554 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
555
556 if (!match) {
557 // forward reference in *merge_cp_p or not a direct match
558 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
559 _operands_cur_length, THREAD);
560 if (found_i != -1) {
561 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
562 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
563 new_bs_i = found_i;
564 map_operand_index(old_bs_i, found_i);
565 } else {
566 // no match found so we have to append this bootstrap specifier to *merge_cp_p
567 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
568 new_bs_i = _operands_cur_length - 1;
569 }
570 }
571 return new_bs_i;
572 } // end find_or_append_operand()
573
574
575 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
576 if (merge_cp->operands() == NULL) {
577 return;
578 }
579 // Shrink the merge_cp operands
580 merge_cp->shrink_operands(_operands_cur_length, CHECK);
581
582 if (RC_TRACE_ENABLED(0x00040000)) {
583 // don't want to loop unless we are tracing
584 int count = 0;
585 for (int i = 1; i < _operands_index_map_p->length(); i++) {
586 int value = _operands_index_map_p->at(i);
587 if (value != -1) {
588 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
589 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
590 count++;
591 }
592 }
593 }
594 // Clean-up
595 _operands_index_map_p = NULL;
596 _operands_cur_length = 0;
597 _operands_index_map_count = 0;
598 } // end finalize_operands_merge()
599
600
601 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
602 instanceKlassHandle the_class,
603 instanceKlassHandle scratch_class) {
604 int i;
605
606 // Check superclasses, or rather their names, since superclasses themselves can be
607 // requested to replace.
608 // Check for NULL superclass first since this might be java.lang.Object
609 if (the_class->super() != scratch_class->super() &&
610 (the_class->super() == NULL || scratch_class->super() == NULL ||
611 the_class->super()->name() !=
612 scratch_class->super()->name())) {
613 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
614 }
615
616 // Check if the number, names and order of directly implemented interfaces are the same.
617 // I think in principle we should just check if the sets of names of directly implemented
618 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
619 // .java file, also changes in .class file) should not matter. However, comparing sets is
620 // technically a bit more difficult, and, more importantly, I am not sure at present that the
621 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
622 // rely on it somewhere.
623 Array<Klass*>* k_interfaces = the_class->local_interfaces();
624 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
625 int n_intfs = k_interfaces->length();
626 if (n_intfs != k_new_interfaces->length()) {
627 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
628 }
629 for (i = 0; i < n_intfs; i++) {
630 if (k_interfaces->at(i)->name() !=
631 k_new_interfaces->at(i)->name()) {
632 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
633 }
634 }
635
636 // Check whether class is in the error init state.
637 if (the_class->is_in_error_state()) {
638 // TBD #5057930: special error code is needed in 1.6
639 return JVMTI_ERROR_INVALID_CLASS;
640 }
641
642 // Check whether class modifiers are the same.
643 jushort old_flags = (jushort) the_class->access_flags().get_flags();
644 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
645 if (old_flags != new_flags) {
646 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
647 }
648
649 // Check if the number, names, types and order of fields declared in these classes
650 // are the same.
651 JavaFieldStream old_fs(the_class);
652 JavaFieldStream new_fs(scratch_class);
653 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
654 // access
655 old_flags = old_fs.access_flags().as_short();
656 new_flags = new_fs.access_flags().as_short();
657 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
658 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
659 }
660 // offset
661 if (old_fs.offset() != new_fs.offset()) {
662 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
663 }
664 // name and signature
665 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
666 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
667 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
668 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
669 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
670 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
671 }
672 }
673
674 // If both streams aren't done then we have a differing number of
675 // fields.
676 if (!old_fs.done() || !new_fs.done()) {
677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
678 }
679
680 // Do a parallel walk through the old and new methods. Detect
681 // cases where they match (exist in both), have been added in
682 // the new methods, or have been deleted (exist only in the
683 // old methods). The class file parser places methods in order
684 // by method name, but does not order overloaded methods by
685 // signature. In order to determine what fate befell the methods,
686 // this code places the overloaded new methods that have matching
687 // old methods in the same order as the old methods and places
688 // new overloaded methods at the end of overloaded methods of
689 // that name. The code for this order normalization is adapted
690 // from the algorithm used in InstanceKlass::find_method().
691 // Since we are swapping out of order entries as we find them,
692 // we only have to search forward through the overloaded methods.
693 // Methods which are added and have the same name as an existing
694 // method (but different signature) will be put at the end of
695 // the methods with that name, and the name mismatch code will
696 // handle them.
697 Array<Method*>* k_old_methods(the_class->methods());
698 Array<Method*>* k_new_methods(scratch_class->methods());
699 int n_old_methods = k_old_methods->length();
700 int n_new_methods = k_new_methods->length();
701 Thread* thread = Thread::current();
702
703 int ni = 0;
704 int oi = 0;
705 while (true) {
706 Method* k_old_method;
707 Method* k_new_method;
708 enum { matched, added, deleted, undetermined } method_was = undetermined;
709
710 if (oi >= n_old_methods) {
711 if (ni >= n_new_methods) {
712 break; // we've looked at everything, done
713 }
714 // New method at the end
715 k_new_method = k_new_methods->at(ni);
716 method_was = added;
717 } else if (ni >= n_new_methods) {
718 // Old method, at the end, is deleted
719 k_old_method = k_old_methods->at(oi);
720 method_was = deleted;
721 } else {
722 // There are more methods in both the old and new lists
723 k_old_method = k_old_methods->at(oi);
724 k_new_method = k_new_methods->at(ni);
725 if (k_old_method->name() != k_new_method->name()) {
726 // Methods are sorted by method name, so a mismatch means added
727 // or deleted
728 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
729 method_was = added;
730 } else {
731 method_was = deleted;
732 }
733 } else if (k_old_method->signature() == k_new_method->signature()) {
734 // Both the name and signature match
735 method_was = matched;
736 } else {
737 // The name matches, but the signature doesn't, which means we have to
738 // search forward through the new overloaded methods.
739 int nj; // outside the loop for post-loop check
740 for (nj = ni + 1; nj < n_new_methods; nj++) {
741 Method* m = k_new_methods->at(nj);
742 if (k_old_method->name() != m->name()) {
743 // reached another method name so no more overloaded methods
744 method_was = deleted;
745 break;
746 }
747 if (k_old_method->signature() == m->signature()) {
748 // found a match so swap the methods
749 k_new_methods->at_put(ni, m);
750 k_new_methods->at_put(nj, k_new_method);
751 k_new_method = m;
752 method_was = matched;
753 break;
754 }
755 }
756
757 if (nj >= n_new_methods) {
758 // reached the end without a match; so method was deleted
759 method_was = deleted;
760 }
761 }
762 }
763
764 switch (method_was) {
765 case matched:
766 // methods match, be sure modifiers do too
767 old_flags = (jushort) k_old_method->access_flags().get_flags();
768 new_flags = (jushort) k_new_method->access_flags().get_flags();
769 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
770 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
771 }
772 {
773 u2 new_num = k_new_method->method_idnum();
774 u2 old_num = k_old_method->method_idnum();
775 if (new_num != old_num) {
776 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
777 if (idnum_owner != NULL) {
778 // There is already a method assigned this idnum -- switch them
779 idnum_owner->set_method_idnum(new_num);
780 }
781 k_new_method->set_method_idnum(old_num);
782 if (thread->has_pending_exception()) {
783 return JVMTI_ERROR_OUT_OF_MEMORY;
784 }
785 }
786 }
787 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
788 k_new_method->name_and_sig_as_C_string(), ni,
789 k_old_method->name_and_sig_as_C_string(), oi));
790 // advance to next pair of methods
791 ++oi;
792 ++ni;
793 break;
794 case added:
795 // method added, see if it is OK
796 new_flags = (jushort) k_new_method->access_flags().get_flags();
797 if ((new_flags & JVM_ACC_PRIVATE) == 0
798 // hack: private should be treated as final, but alas
799 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
800 ) {
801 // new methods must be private
802 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
803 }
804 {
805 u2 num = the_class->next_method_idnum();
806 if (num == ConstMethod::UNSET_IDNUM) {
807 // cannot add any more methods
808 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
809 }
810 u2 new_num = k_new_method->method_idnum();
811 Method* idnum_owner = scratch_class->method_with_idnum(num);
812 if (idnum_owner != NULL) {
813 // There is already a method assigned this idnum -- switch them
814 idnum_owner->set_method_idnum(new_num);
815 }
816 k_new_method->set_method_idnum(num);
817 if (thread->has_pending_exception()) {
818 return JVMTI_ERROR_OUT_OF_MEMORY;
819 }
820 }
821 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
822 k_new_method->name_and_sig_as_C_string(), ni));
823 ++ni; // advance to next new method
824 break;
825 case deleted:
826 // method deleted, see if it is OK
827 old_flags = (jushort) k_old_method->access_flags().get_flags();
828 if ((old_flags & JVM_ACC_PRIVATE) == 0
829 // hack: private should be treated as final, but alas
830 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
831 ) {
832 // deleted methods must be private
833 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
834 }
835 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
836 k_old_method->name_and_sig_as_C_string(), oi));
837 ++oi; // advance to next old method
838 break;
839 default:
840 ShouldNotReachHere();
841 }
842 }
843
844 return JVMTI_ERROR_NONE;
845 }
846
847
848 // Find new constant pool index value for old constant pool index value
849 // by seaching the index map. Returns zero (0) if there is no mapped
850 // value for the old constant pool index.
851 int VM_RedefineClasses::find_new_index(int old_index) {
852 if (_index_map_count == 0) {
853 // map is empty so nothing can be found
854 return 0;
855 }
856
857 if (old_index < 1 || old_index >= _index_map_p->length()) {
858 // The old_index is out of range so it is not mapped. This should
859 // not happen in regular constant pool merging use, but it can
860 // happen if a corrupt annotation is processed.
861 return 0;
862 }
863
864 int value = _index_map_p->at(old_index);
865 if (value == -1) {
866 // the old_index is not mapped
867 return 0;
868 }
869
870 return value;
871 } // end find_new_index()
872
873
874 // Find new bootstrap specifier index value for old bootstrap specifier index
875 // value by seaching the index map. Returns unused index (-1) if there is
876 // no mapped value for the old bootstrap specifier index.
877 int VM_RedefineClasses::find_new_operand_index(int old_index) {
878 if (_operands_index_map_count == 0) {
879 // map is empty so nothing can be found
880 return -1;
881 }
882
883 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
884 // The old_index is out of range so it is not mapped.
885 // This should not happen in regular constant pool merging use.
886 return -1;
887 }
888
889 int value = _operands_index_map_p->at(old_index);
890 if (value == -1) {
891 // the old_index is not mapped
892 return -1;
893 }
894
895 return value;
896 } // end find_new_operand_index()
897
898
899 // Returns true if the current mismatch is due to a resolved/unresolved
900 // class pair. Otherwise, returns false.
901 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
902 int index1, constantPoolHandle cp2, int index2) {
903
904 jbyte t1 = cp1->tag_at(index1).value();
905 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
906 return false; // wrong entry type; not our special case
907 }
908
909 jbyte t2 = cp2->tag_at(index2).value();
910 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
911 return false; // wrong entry type; not our special case
912 }
913
914 if (t1 == t2) {
915 return false; // not a mismatch; not our special case
916 }
917
918 char *s1 = cp1->klass_name_at(index1)->as_C_string();
919 char *s2 = cp2->klass_name_at(index2)->as_C_string();
920 if (strcmp(s1, s2) != 0) {
921 return false; // strings don't match; not our special case
922 }
923
924 return true; // made it through the gauntlet; this is our special case
925 } // end is_unresolved_class_mismatch()
926
927
928 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
929
930 // For consistency allocate memory using os::malloc wrapper.
931 _scratch_classes = (Klass**)
932 os::malloc(sizeof(Klass*) * _class_count, mtClass);
933 if (_scratch_classes == NULL) {
934 return JVMTI_ERROR_OUT_OF_MEMORY;
935 }
936 // Zero initialize the _scratch_classes array.
937 for (int i = 0; i < _class_count; i++) {
938 _scratch_classes[i] = NULL;
939 }
940
941 ResourceMark rm(THREAD);
942
943 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
944 // state can only be NULL if the current thread is exiting which
945 // should not happen since we're trying to do a RedefineClasses
946 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
947 for (int i = 0; i < _class_count; i++) {
948 // Create HandleMark so that any handles created while loading new class
949 // versions are deleted. Constant pools are deallocated while merging
950 // constant pools
951 HandleMark hm(THREAD);
952
953 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
954 // classes for primitives cannot be redefined
955 if (!is_modifiable_class(mirror)) {
956 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
957 }
958 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
959 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
960 Symbol* the_class_sym = the_class->name();
961
962 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
963 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
964 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
965 the_class->external_name(), _class_load_kind,
966 os::available_memory() >> 10));
967
968 ClassFileStream st((u1*) _class_defs[i].class_bytes,
969 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
970
971 // Parse the stream.
972 Handle the_class_loader(THREAD, the_class->class_loader());
973 Handle protection_domain(THREAD, the_class->protection_domain());
974 // Set redefined class handle in JvmtiThreadState class.
975 // This redefined class is sent to agent event handler for class file
976 // load hook event.
977 state->set_class_being_redefined(&the_class, _class_load_kind);
978
979 Klass* k = SystemDictionary::parse_stream(the_class_sym,
980 the_class_loader,
981 protection_domain,
982 &st,
983 THREAD);
984 // Clear class_being_redefined just to be sure.
985 state->clear_class_being_redefined();
986
987 // TODO: if this is retransform, and nothing changed we can skip it
988
989 instanceKlassHandle scratch_class (THREAD, k);
990
991 // Need to clean up allocated InstanceKlass if there's an error so assign
992 // the result here. Caller deallocates all the scratch classes in case of
993 // an error.
994 _scratch_classes[i] = k;
995
996 if (HAS_PENDING_EXCEPTION) {
997 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
998 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
999 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1000 ex_name->as_C_string()));
1001 CLEAR_PENDING_EXCEPTION;
1002
1003 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1004 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1005 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1006 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1007 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1008 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1009 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1010 // The message will be "XXX (wrong name: YYY)"
1011 return JVMTI_ERROR_NAMES_DONT_MATCH;
1012 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1013 return JVMTI_ERROR_OUT_OF_MEMORY;
1014 } else { // Just in case more exceptions can be thrown..
1015 return JVMTI_ERROR_FAILS_VERIFICATION;
1016 }
1017 }
1018
1019 // Ensure class is linked before redefine
1020 if (!the_class->is_linked()) {
1021 the_class->link_class(THREAD);
1022 if (HAS_PENDING_EXCEPTION) {
1023 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1024 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1025 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1026 ex_name->as_C_string()));
1027 CLEAR_PENDING_EXCEPTION;
1028 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1029 return JVMTI_ERROR_OUT_OF_MEMORY;
1030 } else {
1031 return JVMTI_ERROR_INTERNAL;
1032 }
1033 }
1034 }
1035
1036 // Do the validity checks in compare_and_normalize_class_versions()
1037 // before verifying the byte codes. By doing these checks first, we
1038 // limit the number of functions that require redirection from
1039 // the_class to scratch_class. In particular, we don't have to
1040 // modify JNI GetSuperclass() and thus won't change its performance.
1041 jvmtiError res = compare_and_normalize_class_versions(the_class,
1042 scratch_class);
1043 if (res != JVMTI_ERROR_NONE) {
1044 return res;
1045 }
1046
1047 // verify what the caller passed us
1048 {
1049 // The bug 6214132 caused the verification to fail.
1050 // Information about the_class and scratch_class is temporarily
1051 // recorded into jvmtiThreadState. This data is used to redirect
1052 // the_class to scratch_class in the JVM_* functions called by the
1053 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1054 // description.
1055 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1056 Verifier::verify(
1057 scratch_class, Verifier::ThrowException, true, THREAD);
1058 }
1059
1060 if (HAS_PENDING_EXCEPTION) {
1061 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1062 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1063 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1064 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1065 CLEAR_PENDING_EXCEPTION;
1066 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1067 return JVMTI_ERROR_OUT_OF_MEMORY;
1068 } else {
1069 // tell the caller the bytecodes are bad
1070 return JVMTI_ERROR_FAILS_VERIFICATION;
1071 }
1072 }
1073
1074 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1075 if (HAS_PENDING_EXCEPTION) {
1076 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1077 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1078 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1079 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1080 CLEAR_PENDING_EXCEPTION;
1081 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1082 return JVMTI_ERROR_OUT_OF_MEMORY;
1083 } else {
1084 return JVMTI_ERROR_INTERNAL;
1085 }
1086 }
1087
1088 if (VerifyMergedCPBytecodes) {
1089 // verify what we have done during constant pool merging
1090 {
1091 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1092 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1093 }
1094
1095 if (HAS_PENDING_EXCEPTION) {
1096 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1097 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1098 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1099 ("verify_byte_codes post merge-CP exception: '%s'",
1100 ex_name->as_C_string()));
1101 CLEAR_PENDING_EXCEPTION;
1102 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1103 return JVMTI_ERROR_OUT_OF_MEMORY;
1104 } else {
1105 // tell the caller that constant pool merging screwed up
1106 return JVMTI_ERROR_INTERNAL;
1107 }
1108 }
1109 }
1110
1111 Rewriter::rewrite(scratch_class, THREAD);
1112 if (!HAS_PENDING_EXCEPTION) {
1113 scratch_class->link_methods(THREAD);
1114 }
1115 if (HAS_PENDING_EXCEPTION) {
1116 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1117 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1118 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1119 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1120 CLEAR_PENDING_EXCEPTION;
1121 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1122 return JVMTI_ERROR_OUT_OF_MEMORY;
1123 } else {
1124 return JVMTI_ERROR_INTERNAL;
1125 }
1126 }
1127
1128 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1129 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1130 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1131 the_class->external_name(), os::available_memory() >> 10));
1132 }
1133
1134 return JVMTI_ERROR_NONE;
1135 }
1136
1137
1138 // Map old_index to new_index as needed. scratch_cp is only needed
1139 // for RC_TRACE() calls.
1140 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1141 int old_index, int new_index) {
1142 if (find_new_index(old_index) != 0) {
1143 // old_index is already mapped
1144 return;
1145 }
1146
1147 if (old_index == new_index) {
1148 // no mapping is needed
1149 return;
1150 }
1151
1152 _index_map_p->at_put(old_index, new_index);
1153 _index_map_count++;
1154
1155 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1156 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1157 } // end map_index()
1158
1159
1160 // Map old_index to new_index as needed.
1161 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1162 if (find_new_operand_index(old_index) != -1) {
1163 // old_index is already mapped
1164 return;
1165 }
1166
1167 if (old_index == new_index) {
1168 // no mapping is needed
1169 return;
1170 }
1171
1172 _operands_index_map_p->at_put(old_index, new_index);
1173 _operands_index_map_count++;
1174
1175 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1176 } // end map_index()
1177
1178
1179 // Merge old_cp and scratch_cp and return the results of the merge via
1180 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1181 // merge_cp_length_p. The entries in old_cp occupy the same locations
1182 // in *merge_cp_p. Also creates a map of indices from entries in
1183 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1184 // entries are only created for entries in scratch_cp that occupy a
1185 // different location in *merged_cp_p.
1186 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1187 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1188 int *merge_cp_length_p, TRAPS) {
1189
1190 if (merge_cp_p == NULL) {
1191 assert(false, "caller must provide scratch constantPool");
1192 return false; // robustness
1193 }
1194 if (merge_cp_length_p == NULL) {
1195 assert(false, "caller must provide scratch CP length");
1196 return false; // robustness
1197 }
1198 // Worst case we need old_cp->length() + scratch_cp()->length(),
1199 // but the caller might be smart so make sure we have at least
1200 // the minimum.
1201 if ((*merge_cp_p)->length() < old_cp->length()) {
1202 assert(false, "merge area too small");
1203 return false; // robustness
1204 }
1205
1206 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1207 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1208 scratch_cp->length()));
1209
1210 {
1211 // Pass 0:
1212 // The old_cp is copied to *merge_cp_p; this means that any code
1213 // using old_cp does not have to change. This work looks like a
1214 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1215 // handle one special case:
1216 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1217 // This will make verification happy.
1218
1219 int old_i; // index into old_cp
1220
1221 // index zero (0) is not used in constantPools
1222 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1223 // leave debugging crumb
1224 jbyte old_tag = old_cp->tag_at(old_i).value();
1225 switch (old_tag) {
1226 case JVM_CONSTANT_Class:
1227 case JVM_CONSTANT_UnresolvedClass:
1228 // revert the copy to JVM_CONSTANT_UnresolvedClass
1229 // May be resolving while calling this so do the same for
1230 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1231 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1232 old_cp->klass_name_at(old_i));
1233 break;
1234
1235 case JVM_CONSTANT_Double:
1236 case JVM_CONSTANT_Long:
1237 // just copy the entry to *merge_cp_p, but double and long take
1238 // two constant pool entries
1239 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1240 old_i++;
1241 break;
1242
1243 default:
1244 // just copy the entry to *merge_cp_p
1245 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1246 break;
1247 }
1248 } // end for each old_cp entry
1249
1250 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1251 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1252
1253 // We don't need to sanity check that *merge_cp_length_p is within
1254 // *merge_cp_p bounds since we have the minimum on-entry check above.
1255 (*merge_cp_length_p) = old_i;
1256 }
1257
1258 // merge_cp_len should be the same as old_cp->length() at this point
1259 // so this trace message is really a "warm-and-breathing" message.
1260 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1261 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1262
1263 int scratch_i; // index into scratch_cp
1264 {
1265 // Pass 1a:
1266 // Compare scratch_cp entries to the old_cp entries that we have
1267 // already copied to *merge_cp_p. In this pass, we are eliminating
1268 // exact duplicates (matching entry at same index) so we only
1269 // compare entries in the common indice range.
1270 int increment = 1;
1271 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1272 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1273 switch (scratch_cp->tag_at(scratch_i).value()) {
1274 case JVM_CONSTANT_Double:
1275 case JVM_CONSTANT_Long:
1276 // double and long take two constant pool entries
1277 increment = 2;
1278 break;
1279
1280 default:
1281 increment = 1;
1282 break;
1283 }
1284
1285 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1286 scratch_i, CHECK_0);
1287 if (match) {
1288 // found a match at the same index so nothing more to do
1289 continue;
1290 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1291 *merge_cp_p, scratch_i)) {
1292 // The mismatch in compare_entry_to() above is because of a
1293 // resolved versus unresolved class entry at the same index
1294 // with the same string value. Since Pass 0 reverted any
1295 // class entries to unresolved class entries in *merge_cp_p,
1296 // we go with the unresolved class entry.
1297 continue;
1298 }
1299
1300 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1301 CHECK_0);
1302 if (found_i != 0) {
1303 guarantee(found_i != scratch_i,
1304 "compare_entry_to() and find_matching_entry() do not agree");
1305
1306 // Found a matching entry somewhere else in *merge_cp_p so
1307 // just need a mapping entry.
1308 map_index(scratch_cp, scratch_i, found_i);
1309 continue;
1310 }
1311
1312 // The find_matching_entry() call above could fail to find a match
1313 // due to a resolved versus unresolved class or string entry situation
1314 // like we solved above with the is_unresolved_*_mismatch() calls.
1315 // However, we would have to call is_unresolved_*_mismatch() over
1316 // all of *merge_cp_p (potentially) and that doesn't seem to be
1317 // worth the time.
1318
1319 // No match found so we have to append this entry and any unique
1320 // referenced entries to *merge_cp_p.
1321 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1322 CHECK_0);
1323 }
1324 }
1325
1326 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1327 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1328 *merge_cp_length_p, scratch_i, _index_map_count));
1329
1330 if (scratch_i < scratch_cp->length()) {
1331 // Pass 1b:
1332 // old_cp is smaller than scratch_cp so there are entries in
1333 // scratch_cp that we have not yet processed. We take care of
1334 // those now.
1335 int increment = 1;
1336 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1337 switch (scratch_cp->tag_at(scratch_i).value()) {
1338 case JVM_CONSTANT_Double:
1339 case JVM_CONSTANT_Long:
1340 // double and long take two constant pool entries
1341 increment = 2;
1342 break;
1343
1344 default:
1345 increment = 1;
1346 break;
1347 }
1348
1349 int found_i =
1350 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1351 if (found_i != 0) {
1352 // Found a matching entry somewhere else in *merge_cp_p so
1353 // just need a mapping entry.
1354 map_index(scratch_cp, scratch_i, found_i);
1355 continue;
1356 }
1357
1358 // No match found so we have to append this entry and any unique
1359 // referenced entries to *merge_cp_p.
1360 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1361 CHECK_0);
1362 }
1363
1364 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1365 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1366 *merge_cp_length_p, scratch_i, _index_map_count));
1367 }
1368 finalize_operands_merge(*merge_cp_p, THREAD);
1369
1370 return true;
1371 } // end merge_constant_pools()
1372
1373
1374 // Scoped object to clean up the constant pool(s) created for merging
1375 class MergeCPCleaner {
1376 ClassLoaderData* _loader_data;
1377 ConstantPool* _cp;
1378 ConstantPool* _scratch_cp;
1379 public:
1380 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1381 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1382 ~MergeCPCleaner() {
1383 _loader_data->add_to_deallocate_list(_cp);
1384 if (_scratch_cp != NULL) {
1385 _loader_data->add_to_deallocate_list(_scratch_cp);
1386 }
1387 }
1388 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1389 };
1390
1391 // Merge constant pools between the_class and scratch_class and
1392 // potentially rewrite bytecodes in scratch_class to use the merged
1393 // constant pool.
1394 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1395 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1396 TRAPS) {
1397 // worst case merged constant pool length is old and new combined
1398 int merge_cp_length = the_class->constants()->length()
1399 + scratch_class->constants()->length();
1400
1401 // Constant pools are not easily reused so we allocate a new one
1402 // each time.
1403 // merge_cp is created unsafe for concurrent GC processing. It
1404 // should be marked safe before discarding it. Even though
1405 // garbage, if it crosses a card boundary, it may be scanned
1406 // in order to find the start of the first complete object on the card.
1407 ClassLoaderData* loader_data = the_class->class_loader_data();
1408 ConstantPool* merge_cp_oop =
1409 ConstantPool::allocate(loader_data,
1410 merge_cp_length,
1411 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1412 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1413
1414 HandleMark hm(THREAD); // make sure handles are cleared before
1415 // MergeCPCleaner clears out merge_cp_oop
1416 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1417
1418 // Get constants() from the old class because it could have been rewritten
1419 // while we were at a safepoint allocating a new constant pool.
1420 constantPoolHandle old_cp(THREAD, the_class->constants());
1421 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1422
1423 // If the length changed, the class was redefined out from under us. Return
1424 // an error.
1425 if (merge_cp_length != the_class->constants()->length()
1426 + scratch_class->constants()->length()) {
1427 return JVMTI_ERROR_INTERNAL;
1428 }
1429
1430 // Update the version number of the constant pool
1431 merge_cp->increment_and_save_version(old_cp->version());
1432
1433 ResourceMark rm(THREAD);
1434 _index_map_count = 0;
1435 _index_map_p = new intArray(scratch_cp->length(), -1);
1436
1437 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1438 _operands_index_map_count = 0;
1439 _operands_index_map_p = new intArray(
1440 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1441
1442 // reference to the cp holder is needed for copy_operands()
1443 merge_cp->set_pool_holder(scratch_class());
1444 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1445 &merge_cp_length, THREAD);
1446 merge_cp->set_pool_holder(NULL);
1447
1448 if (!result) {
1449 // The merge can fail due to memory allocation failure or due
1450 // to robustness checks.
1451 return JVMTI_ERROR_INTERNAL;
1452 }
1453
1454 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1455 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1456
1457 if (_index_map_count == 0) {
1458 // there is nothing to map between the new and merged constant pools
1459
1460 if (old_cp->length() == scratch_cp->length()) {
1461 // The old and new constant pools are the same length and the
1462 // index map is empty. This means that the three constant pools
1463 // are equivalent (but not the same). Unfortunately, the new
1464 // constant pool has not gone through link resolution nor have
1465 // the new class bytecodes gone through constant pool cache
1466 // rewriting so we can't use the old constant pool with the new
1467 // class.
1468
1469 // toss the merged constant pool at return
1470 } else if (old_cp->length() < scratch_cp->length()) {
1471 // The old constant pool has fewer entries than the new constant
1472 // pool and the index map is empty. This means the new constant
1473 // pool is a superset of the old constant pool. However, the old
1474 // class bytecodes have already gone through constant pool cache
1475 // rewriting so we can't use the new constant pool with the old
1476 // class.
1477
1478 // toss the merged constant pool at return
1479 } else {
1480 // The old constant pool has more entries than the new constant
1481 // pool and the index map is empty. This means that both the old
1482 // and merged constant pools are supersets of the new constant
1483 // pool.
1484
1485 // Replace the new constant pool with a shrunken copy of the
1486 // merged constant pool
1487 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1488 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1489 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1490 // It can't be cleaned up while there are handles to it.
1491 cp_cleaner.add_scratch_cp(scratch_cp());
1492 }
1493 } else {
1494 if (RC_TRACE_ENABLED(0x00040000)) {
1495 // don't want to loop unless we are tracing
1496 int count = 0;
1497 for (int i = 1; i < _index_map_p->length(); i++) {
1498 int value = _index_map_p->at(i);
1499
1500 if (value != -1) {
1501 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1502 ("index_map[%d]: old=%d new=%d", count, i, value));
1503 count++;
1504 }
1505 }
1506 }
1507
1508 // We have entries mapped between the new and merged constant pools
1509 // so we have to rewrite some constant pool references.
1510 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1511 return JVMTI_ERROR_INTERNAL;
1512 }
1513
1514 // Replace the new constant pool with a shrunken copy of the
1515 // merged constant pool so now the rewritten bytecodes have
1516 // valid references; the previous new constant pool will get
1517 // GCed.
1518 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1519 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1520 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1521 // It can't be cleaned up while there are handles to it.
1522 cp_cleaner.add_scratch_cp(scratch_cp());
1523 }
1524
1525 return JVMTI_ERROR_NONE;
1526 } // end merge_cp_and_rewrite()
1527
1528
1529 // Rewrite constant pool references in klass scratch_class.
1530 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1531 TRAPS) {
1532
1533 // rewrite constant pool references in the methods:
1534 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1535 // propagate failure back to caller
1536 return false;
1537 }
1538
1539 // rewrite constant pool references in the class_annotations:
1540 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1541 // propagate failure back to caller
1542 return false;
1543 }
1544
1545 // rewrite constant pool references in the fields_annotations:
1546 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1547 // propagate failure back to caller
1548 return false;
1549 }
1550
1551 // rewrite constant pool references in the methods_annotations:
1552 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1553 // propagate failure back to caller
1554 return false;
1555 }
1556
1557 // rewrite constant pool references in the methods_parameter_annotations:
1558 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1559 THREAD)) {
1560 // propagate failure back to caller
1561 return false;
1562 }
1563
1564 // rewrite constant pool references in the methods_default_annotations:
1565 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1566 THREAD)) {
1567 // propagate failure back to caller
1568 return false;
1569 }
1570
1571 // rewrite source file name index:
1572 u2 source_file_name_idx = scratch_class->source_file_name_index();
1573 if (source_file_name_idx != 0) {
1574 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1575 if (new_source_file_name_idx != 0) {
1576 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1577 }
1578 }
1579
1580 // rewrite class generic signature index:
1581 u2 generic_signature_index = scratch_class->generic_signature_index();
1582 if (generic_signature_index != 0) {
1583 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1584 if (new_generic_signature_index != 0) {
1585 scratch_class->set_generic_signature_index(new_generic_signature_index);
1586 }
1587 }
1588
1589 return true;
1590 } // end rewrite_cp_refs()
1591
1592 // Rewrite constant pool references in the methods.
1593 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1594 instanceKlassHandle scratch_class, TRAPS) {
1595
1596 Array<Method*>* methods = scratch_class->methods();
1597
1598 if (methods == NULL || methods->length() == 0) {
1599 // no methods so nothing to do
1600 return true;
1601 }
1602
1603 // rewrite constant pool references in the methods:
1604 for (int i = methods->length() - 1; i >= 0; i--) {
1605 methodHandle method(THREAD, methods->at(i));
1606 methodHandle new_method;
1607 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1608 if (!new_method.is_null()) {
1609 // the method has been replaced so save the new method version
1610 // even in the case of an exception. original method is on the
1611 // deallocation list.
1612 methods->at_put(i, new_method());
1613 }
1614 if (HAS_PENDING_EXCEPTION) {
1615 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1616 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1617 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1618 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1619 // Need to clear pending exception here as the super caller sets
1620 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1621 CLEAR_PENDING_EXCEPTION;
1622 return false;
1623 }
1624 }
1625
1626 return true;
1627 }
1628
1629
1630 // Rewrite constant pool references in the specific method. This code
1631 // was adapted from Rewriter::rewrite_method().
1632 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1633 methodHandle *new_method_p, TRAPS) {
1634
1635 *new_method_p = methodHandle(); // default is no new method
1636
1637 // We cache a pointer to the bytecodes here in code_base. If GC
1638 // moves the Method*, then the bytecodes will also move which
1639 // will likely cause a crash. We create a No_Safepoint_Verifier
1640 // object to detect whether we pass a possible safepoint in this
1641 // code block.
1642 No_Safepoint_Verifier nsv;
1643
1644 // Bytecodes and their length
1645 address code_base = method->code_base();
1646 int code_length = method->code_size();
1647
1648 int bc_length;
1649 for (int bci = 0; bci < code_length; bci += bc_length) {
1650 address bcp = code_base + bci;
1651 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1652
1653 bc_length = Bytecodes::length_for(c);
1654 if (bc_length == 0) {
1655 // More complicated bytecodes report a length of zero so
1656 // we have to try again a slightly different way.
1657 bc_length = Bytecodes::length_at(method(), bcp);
1658 }
1659
1660 assert(bc_length != 0, "impossible bytecode length");
1661
1662 switch (c) {
1663 case Bytecodes::_ldc:
1664 {
1665 int cp_index = *(bcp + 1);
1666 int new_index = find_new_index(cp_index);
1667
1668 if (StressLdcRewrite && new_index == 0) {
1669 // If we are stressing ldc -> ldc_w rewriting, then we
1670 // always need a new_index value.
1671 new_index = cp_index;
1672 }
1673 if (new_index != 0) {
1674 // the original index is mapped so we have more work to do
1675 if (!StressLdcRewrite && new_index <= max_jubyte) {
1676 // The new value can still use ldc instead of ldc_w
1677 // unless we are trying to stress ldc -> ldc_w rewriting
1678 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1679 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1680 bcp, cp_index, new_index));
1681 *(bcp + 1) = new_index;
1682 } else {
1683 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1684 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1685 Bytecodes::name(c), bcp, cp_index, new_index));
1686 // the new value needs ldc_w instead of ldc
1687 u_char inst_buffer[4]; // max instruction size is 4 bytes
1688 bcp = (address)inst_buffer;
1689 // construct new instruction sequence
1690 *bcp = Bytecodes::_ldc_w;
1691 bcp++;
1692 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1693 // See comment below for difference between put_Java_u2()
1694 // and put_native_u2().
1695 Bytes::put_Java_u2(bcp, new_index);
1696
1697 Relocator rc(method, NULL /* no RelocatorListener needed */);
1698 methodHandle m;
1699 {
1700 Pause_No_Safepoint_Verifier pnsv(&nsv);
1701
1702 // ldc is 2 bytes and ldc_w is 3 bytes
1703 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1704 }
1705
1706 // return the new method so that the caller can update
1707 // the containing class
1708 *new_method_p = method = m;
1709 // switch our bytecode processing loop from the old method
1710 // to the new method
1711 code_base = method->code_base();
1712 code_length = method->code_size();
1713 bcp = code_base + bci;
1714 c = (Bytecodes::Code)(*bcp);
1715 bc_length = Bytecodes::length_for(c);
1716 assert(bc_length != 0, "sanity check");
1717 } // end we need ldc_w instead of ldc
1718 } // end if there is a mapped index
1719 } break;
1720
1721 // these bytecodes have a two-byte constant pool index
1722 case Bytecodes::_anewarray : // fall through
1723 case Bytecodes::_checkcast : // fall through
1724 case Bytecodes::_getfield : // fall through
1725 case Bytecodes::_getstatic : // fall through
1726 case Bytecodes::_instanceof : // fall through
1727 case Bytecodes::_invokedynamic : // fall through
1728 case Bytecodes::_invokeinterface: // fall through
1729 case Bytecodes::_invokespecial : // fall through
1730 case Bytecodes::_invokestatic : // fall through
1731 case Bytecodes::_invokevirtual : // fall through
1732 case Bytecodes::_ldc_w : // fall through
1733 case Bytecodes::_ldc2_w : // fall through
1734 case Bytecodes::_multianewarray : // fall through
1735 case Bytecodes::_new : // fall through
1736 case Bytecodes::_putfield : // fall through
1737 case Bytecodes::_putstatic :
1738 {
1739 address p = bcp + 1;
1740 int cp_index = Bytes::get_Java_u2(p);
1741 int new_index = find_new_index(cp_index);
1742 if (new_index != 0) {
1743 // the original index is mapped so update w/ new value
1744 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1745 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1746 bcp, cp_index, new_index));
1747 // Rewriter::rewrite_method() uses put_native_u2() in this
1748 // situation because it is reusing the constant pool index
1749 // location for a native index into the ConstantPoolCache.
1750 // Since we are updating the constant pool index prior to
1751 // verification and ConstantPoolCache initialization, we
1752 // need to keep the new index in Java byte order.
1753 Bytes::put_Java_u2(p, new_index);
1754 }
1755 } break;
1756 }
1757 } // end for each bytecode
1758
1759 // We also need to rewrite the parameter name indexes, if there is
1760 // method parameter data present
1761 if(method->has_method_parameters()) {
1762 const int len = method->method_parameters_length();
1763 MethodParametersElement* elem = method->method_parameters_start();
1764
1765 for (int i = 0; i < len; i++) {
1766 const u2 cp_index = elem[i].name_cp_index;
1767 const u2 new_cp_index = find_new_index(cp_index);
1768 if (new_cp_index != 0) {
1769 elem[i].name_cp_index = new_cp_index;
1770 }
1771 }
1772 }
1773 } // end rewrite_cp_refs_in_method()
1774
1775
1776 // Rewrite constant pool references in the class_annotations field.
1777 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1778 instanceKlassHandle scratch_class, TRAPS) {
1779
1780 AnnotationArray* class_annotations = scratch_class->class_annotations();
1781 if (class_annotations == NULL || class_annotations->length() == 0) {
1782 // no class_annotations so nothing to do
1783 return true;
1784 }
1785
1786 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1787 ("class_annotations length=%d", class_annotations->length()));
1788
1789 int byte_i = 0; // byte index into class_annotations
1790 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1791 THREAD);
1792 }
1793
1794
1795 // Rewrite constant pool references in an annotations typeArray. This
1796 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1797 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1798 //
1799 // annotations_typeArray {
1800 // u2 num_annotations;
1801 // annotation annotations[num_annotations];
1802 // }
1803 //
1804 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1805 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1806
1807 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1808 // not enough room for num_annotations field
1809 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1810 ("length() is too small for num_annotations field"));
1811 return false;
1812 }
1813
1814 u2 num_annotations = Bytes::get_Java_u2((address)
1815 annotations_typeArray->adr_at(byte_i_ref));
1816 byte_i_ref += 2;
1817
1818 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1819 ("num_annotations=%d", num_annotations));
1820
1821 int calc_num_annotations = 0;
1822 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1823 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1824 byte_i_ref, THREAD)) {
1825 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1826 ("bad annotation_struct at %d", calc_num_annotations));
1827 // propagate failure back to caller
1828 return false;
1829 }
1830 }
1831 assert(num_annotations == calc_num_annotations, "sanity check");
1832
1833 return true;
1834 } // end rewrite_cp_refs_in_annotations_typeArray()
1835
1836
1837 // Rewrite constant pool references in the annotation struct portion of
1838 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1839 // the 2nd-edition of the VM spec:
1840 //
1841 // struct annotation {
1842 // u2 type_index;
1843 // u2 num_element_value_pairs;
1844 // {
1845 // u2 element_name_index;
1846 // element_value value;
1847 // } element_value_pairs[num_element_value_pairs];
1848 // }
1849 //
1850 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1851 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1852 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1853 // not enough room for smallest annotation_struct
1854 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1855 ("length() is too small for annotation_struct"));
1856 return false;
1857 }
1858
1859 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1860 byte_i_ref, "mapped old type_index=%d", THREAD);
1861
1862 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1863 annotations_typeArray->adr_at(byte_i_ref));
1864 byte_i_ref += 2;
1865
1866 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1867 ("type_index=%d num_element_value_pairs=%d", type_index,
1868 num_element_value_pairs));
1869
1870 int calc_num_element_value_pairs = 0;
1871 for (; calc_num_element_value_pairs < num_element_value_pairs;
1872 calc_num_element_value_pairs++) {
1873 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1874 // not enough room for another element_name_index, let alone
1875 // the rest of another component
1876 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1877 ("length() is too small for element_name_index"));
1878 return false;
1879 }
1880
1881 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1882 annotations_typeArray, byte_i_ref,
1883 "mapped old element_name_index=%d", THREAD);
1884
1885 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1886 ("element_name_index=%d", element_name_index));
1887
1888 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1889 byte_i_ref, THREAD)) {
1890 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1891 ("bad element_value at %d", calc_num_element_value_pairs));
1892 // propagate failure back to caller
1893 return false;
1894 }
1895 } // end for each component
1896 assert(num_element_value_pairs == calc_num_element_value_pairs,
1897 "sanity check");
1898
1899 return true;
1900 } // end rewrite_cp_refs_in_annotation_struct()
1901
1902
1903 // Rewrite a constant pool reference at the current position in
1904 // annotations_typeArray if needed. Returns the original constant
1905 // pool reference if a rewrite was not needed or the new constant
1906 // pool reference if a rewrite was needed.
1907 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1908 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1909 const char * trace_mesg, TRAPS) {
1910
1911 address cp_index_addr = (address)
1912 annotations_typeArray->adr_at(byte_i_ref);
1913 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1914 u2 new_cp_index = find_new_index(old_cp_index);
1915 if (new_cp_index != 0) {
1916 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1917 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1918 old_cp_index = new_cp_index;
1919 }
1920 byte_i_ref += 2;
1921 return old_cp_index;
1922 }
1923
1924
1925 // Rewrite constant pool references in the element_value portion of an
1926 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1927 // the 2nd-edition of the VM spec:
1928 //
1929 // struct element_value {
1930 // u1 tag;
1931 // union {
1932 // u2 const_value_index;
1933 // {
1934 // u2 type_name_index;
1935 // u2 const_name_index;
1936 // } enum_const_value;
1937 // u2 class_info_index;
1938 // annotation annotation_value;
1939 // struct {
1940 // u2 num_values;
1941 // element_value values[num_values];
1942 // } array_value;
1943 // } value;
1944 // }
1945 //
1946 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1947 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1948
1949 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1950 // not enough room for a tag let alone the rest of an element_value
1951 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1952 ("length() is too small for a tag"));
1953 return false;
1954 }
1955
1956 u1 tag = annotations_typeArray->at(byte_i_ref);
1957 byte_i_ref++;
1958 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1959
1960 switch (tag) {
1961 // These BaseType tag values are from Table 4.2 in VM spec:
1962 case 'B': // byte
1963 case 'C': // char
1964 case 'D': // double
1965 case 'F': // float
1966 case 'I': // int
1967 case 'J': // long
1968 case 'S': // short
1969 case 'Z': // boolean
1970
1971 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1972 // the VM spec:
1973 case 's':
1974 {
1975 // For the above tag values (including the BaseType values),
1976 // value.const_value_index is right union field.
1977
1978 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1979 // not enough room for a const_value_index
1980 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1981 ("length() is too small for a const_value_index"));
1982 return false;
1983 }
1984
1985 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1986 annotations_typeArray, byte_i_ref,
1987 "mapped old const_value_index=%d", THREAD);
1988
1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1990 ("const_value_index=%d", const_value_index));
1991 } break;
1992
1993 case 'e':
1994 {
1995 // for the above tag value, value.enum_const_value is right union field
1996
1997 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1998 // not enough room for a enum_const_value
1999 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2000 ("length() is too small for a enum_const_value"));
2001 return false;
2002 }
2003
2004 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2005 annotations_typeArray, byte_i_ref,
2006 "mapped old type_name_index=%d", THREAD);
2007
2008 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2009 annotations_typeArray, byte_i_ref,
2010 "mapped old const_name_index=%d", THREAD);
2011
2012 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2013 ("type_name_index=%d const_name_index=%d", type_name_index,
2014 const_name_index));
2015 } break;
2016
2017 case 'c':
2018 {
2019 // for the above tag value, value.class_info_index is right union field
2020
2021 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2022 // not enough room for a class_info_index
2023 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2024 ("length() is too small for a class_info_index"));
2025 return false;
2026 }
2027
2028 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2029 annotations_typeArray, byte_i_ref,
2030 "mapped old class_info_index=%d", THREAD);
2031
2032 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2033 ("class_info_index=%d", class_info_index));
2034 } break;
2035
2036 case '@':
2037 // For the above tag value, value.attr_value is the right union
2038 // field. This is a nested annotation.
2039 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2040 byte_i_ref, THREAD)) {
2041 // propagate failure back to caller
2042 return false;
2043 }
2044 break;
2045
2046 case '[':
2047 {
2048 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2049 // not enough room for a num_values field
2050 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2051 ("length() is too small for a num_values field"));
2052 return false;
2053 }
2054
2055 // For the above tag value, value.array_value is the right union
2056 // field. This is an array of nested element_value.
2057 u2 num_values = Bytes::get_Java_u2((address)
2058 annotations_typeArray->adr_at(byte_i_ref));
2059 byte_i_ref += 2;
2060 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2061
2062 int calc_num_values = 0;
2063 for (; calc_num_values < num_values; calc_num_values++) {
2064 if (!rewrite_cp_refs_in_element_value(
2065 annotations_typeArray, byte_i_ref, THREAD)) {
2066 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2067 ("bad nested element_value at %d", calc_num_values));
2068 // propagate failure back to caller
2069 return false;
2070 }
2071 }
2072 assert(num_values == calc_num_values, "sanity check");
2073 } break;
2074
2075 default:
2076 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2077 return false;
2078 } // end decode tag field
2079
2080 return true;
2081 } // end rewrite_cp_refs_in_element_value()
2082
2083
2084 // Rewrite constant pool references in a fields_annotations field.
2085 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2086 instanceKlassHandle scratch_class, TRAPS) {
2087
2088 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2089
2090 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2091 // no fields_annotations so nothing to do
2092 return true;
2093 }
2094
2095 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2096 ("fields_annotations length=%d", fields_annotations->length()));
2097
2098 for (int i = 0; i < fields_annotations->length(); i++) {
2099 AnnotationArray* field_annotations = fields_annotations->at(i);
2100 if (field_annotations == NULL || field_annotations->length() == 0) {
2101 // this field does not have any annotations so skip it
2102 continue;
2103 }
2104
2105 int byte_i = 0; // byte index into field_annotations
2106 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2107 THREAD)) {
2108 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2109 ("bad field_annotations at %d", i));
2110 // propagate failure back to caller
2111 return false;
2112 }
2113 }
2114
2115 return true;
2116 } // end rewrite_cp_refs_in_fields_annotations()
2117
2118
2119 // Rewrite constant pool references in a methods_annotations field.
2120 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2121 instanceKlassHandle scratch_class, TRAPS) {
2122
2123 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2124 Method* m = scratch_class->methods()->at(i);
2125 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2126
2127 if (method_annotations == NULL || method_annotations->length() == 0) {
2128 // this method does not have any annotations so skip it
2129 continue;
2130 }
2131
2132 int byte_i = 0; // byte index into method_annotations
2133 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2134 THREAD)) {
2135 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2136 ("bad method_annotations at %d", i));
2137 // propagate failure back to caller
2138 return false;
2139 }
2140 }
2141
2142 return true;
2143 } // end rewrite_cp_refs_in_methods_annotations()
2144
2145
2146 // Rewrite constant pool references in a methods_parameter_annotations
2147 // field. This "structure" is adapted from the
2148 // RuntimeVisibleParameterAnnotations_attribute described in section
2149 // 4.8.17 of the 2nd-edition of the VM spec:
2150 //
2151 // methods_parameter_annotations_typeArray {
2152 // u1 num_parameters;
2153 // {
2154 // u2 num_annotations;
2155 // annotation annotations[num_annotations];
2156 // } parameter_annotations[num_parameters];
2157 // }
2158 //
2159 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2160 instanceKlassHandle scratch_class, TRAPS) {
2161
2162 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2163 Method* m = scratch_class->methods()->at(i);
2164 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2165 if (method_parameter_annotations == NULL
2166 || method_parameter_annotations->length() == 0) {
2167 // this method does not have any parameter annotations so skip it
2168 continue;
2169 }
2170
2171 if (method_parameter_annotations->length() < 1) {
2172 // not enough room for a num_parameters field
2173 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2174 ("length() is too small for a num_parameters field at %d", i));
2175 return false;
2176 }
2177
2178 int byte_i = 0; // byte index into method_parameter_annotations
2179
2180 u1 num_parameters = method_parameter_annotations->at(byte_i);
2181 byte_i++;
2182
2183 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2184 ("num_parameters=%d", num_parameters));
2185
2186 int calc_num_parameters = 0;
2187 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2188 if (!rewrite_cp_refs_in_annotations_typeArray(
2189 method_parameter_annotations, byte_i, THREAD)) {
2190 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2191 ("bad method_parameter_annotations at %d", calc_num_parameters));
2192 // propagate failure back to caller
2193 return false;
2194 }
2195 }
2196 assert(num_parameters == calc_num_parameters, "sanity check");
2197 }
2198
2199 return true;
2200 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2201
2202
2203 // Rewrite constant pool references in a methods_default_annotations
2204 // field. This "structure" is adapted from the AnnotationDefault_attribute
2205 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2206 //
2207 // methods_default_annotations_typeArray {
2208 // element_value default_value;
2209 // }
2210 //
2211 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2212 instanceKlassHandle scratch_class, TRAPS) {
2213
2214 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2215 Method* m = scratch_class->methods()->at(i);
2216 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2217 if (method_default_annotations == NULL
2218 || method_default_annotations->length() == 0) {
2219 // this method does not have any default annotations so skip it
2220 continue;
2221 }
2222
2223 int byte_i = 0; // byte index into method_default_annotations
2224
2225 if (!rewrite_cp_refs_in_element_value(
2226 method_default_annotations, byte_i, THREAD)) {
2227 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2228 ("bad default element_value at %d", i));
2229 // propagate failure back to caller
2230 return false;
2231 }
2232 }
2233
2234 return true;
2235 } // end rewrite_cp_refs_in_methods_default_annotations()
2236
2237
2238 // Rewrite constant pool references in the method's stackmap table.
2239 // These "structures" are adapted from the StackMapTable_attribute that
2240 // is described in section 4.8.4 of the 6.0 version of the VM spec
2241 // (dated 2005.10.26):
2242 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2243 //
2244 // stack_map {
2245 // u2 number_of_entries;
2246 // stack_map_frame entries[number_of_entries];
2247 // }
2248 //
2249 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2250 methodHandle method, TRAPS) {
2251
2252 if (!method->has_stackmap_table()) {
2253 return;
2254 }
2255
2256 AnnotationArray* stackmap_data = method->stackmap_data();
2257 address stackmap_p = (address)stackmap_data->adr_at(0);
2258 address stackmap_end = stackmap_p + stackmap_data->length();
2259
2260 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2261 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2262 stackmap_p += 2;
2263
2264 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2265 ("number_of_entries=%u", number_of_entries));
2266
2267 // walk through each stack_map_frame
2268 u2 calc_number_of_entries = 0;
2269 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2270 // The stack_map_frame structure is a u1 frame_type followed by
2271 // 0 or more bytes of data:
2272 //
2273 // union stack_map_frame {
2274 // same_frame;
2275 // same_locals_1_stack_item_frame;
2276 // same_locals_1_stack_item_frame_extended;
2277 // chop_frame;
2278 // same_frame_extended;
2279 // append_frame;
2280 // full_frame;
2281 // }
2282
2283 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2284 // The Linux compiler does not like frame_type to be u1 or u2. It
2285 // issues the following warning for the first if-statement below:
2286 //
2287 // "warning: comparison is always true due to limited range of data type"
2288 //
2289 u4 frame_type = *stackmap_p;
2290 stackmap_p++;
2291
2292 // same_frame {
2293 // u1 frame_type = SAME; /* 0-63 */
2294 // }
2295 if (frame_type >= 0 && frame_type <= 63) {
2296 // nothing more to do for same_frame
2297 }
2298
2299 // same_locals_1_stack_item_frame {
2300 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2301 // verification_type_info stack[1];
2302 // }
2303 else if (frame_type >= 64 && frame_type <= 127) {
2304 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2305 calc_number_of_entries, frame_type, THREAD);
2306 }
2307
2308 // reserved for future use
2309 else if (frame_type >= 128 && frame_type <= 246) {
2310 // nothing more to do for reserved frame_types
2311 }
2312
2313 // same_locals_1_stack_item_frame_extended {
2314 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2315 // u2 offset_delta;
2316 // verification_type_info stack[1];
2317 // }
2318 else if (frame_type == 247) {
2319 stackmap_p += 2;
2320 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2321 calc_number_of_entries, frame_type, THREAD);
2322 }
2323
2324 // chop_frame {
2325 // u1 frame_type = CHOP; /* 248-250 */
2326 // u2 offset_delta;
2327 // }
2328 else if (frame_type >= 248 && frame_type <= 250) {
2329 stackmap_p += 2;
2330 }
2331
2332 // same_frame_extended {
2333 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2334 // u2 offset_delta;
2335 // }
2336 else if (frame_type == 251) {
2337 stackmap_p += 2;
2338 }
2339
2340 // append_frame {
2341 // u1 frame_type = APPEND; /* 252-254 */
2342 // u2 offset_delta;
2343 // verification_type_info locals[frame_type - 251];
2344 // }
2345 else if (frame_type >= 252 && frame_type <= 254) {
2346 assert(stackmap_p + 2 <= stackmap_end,
2347 "no room for offset_delta");
2348 stackmap_p += 2;
2349 u1 len = frame_type - 251;
2350 for (u1 i = 0; i < len; i++) {
2351 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2352 calc_number_of_entries, frame_type, THREAD);
2353 }
2354 }
2355
2356 // full_frame {
2357 // u1 frame_type = FULL_FRAME; /* 255 */
2358 // u2 offset_delta;
2359 // u2 number_of_locals;
2360 // verification_type_info locals[number_of_locals];
2361 // u2 number_of_stack_items;
2362 // verification_type_info stack[number_of_stack_items];
2363 // }
2364 else if (frame_type == 255) {
2365 assert(stackmap_p + 2 + 2 <= stackmap_end,
2366 "no room for smallest full_frame");
2367 stackmap_p += 2;
2368
2369 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2370 stackmap_p += 2;
2371
2372 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2373 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2374 calc_number_of_entries, frame_type, THREAD);
2375 }
2376
2377 // Use the largest size for the number_of_stack_items, but only get
2378 // the right number of bytes.
2379 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2380 stackmap_p += 2;
2381
2382 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2383 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2384 calc_number_of_entries, frame_type, THREAD);
2385 }
2386 }
2387 } // end while there is a stack_map_frame
2388 assert(number_of_entries == calc_number_of_entries, "sanity check");
2389 } // end rewrite_cp_refs_in_stack_map_table()
2390
2391
2392 // Rewrite constant pool references in the verification type info
2393 // portion of the method's stackmap table. These "structures" are
2394 // adapted from the StackMapTable_attribute that is described in
2395 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2396 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2397 //
2398 // The verification_type_info structure is a u1 tag followed by 0 or
2399 // more bytes of data:
2400 //
2401 // union verification_type_info {
2402 // Top_variable_info;
2403 // Integer_variable_info;
2404 // Float_variable_info;
2405 // Long_variable_info;
2406 // Double_variable_info;
2407 // Null_variable_info;
2408 // UninitializedThis_variable_info;
2409 // Object_variable_info;
2410 // Uninitialized_variable_info;
2411 // }
2412 //
2413 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2414 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2415 u1 frame_type, TRAPS) {
2416
2417 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2418 u1 tag = *stackmap_p_ref;
2419 stackmap_p_ref++;
2420
2421 switch (tag) {
2422 // Top_variable_info {
2423 // u1 tag = ITEM_Top; /* 0 */
2424 // }
2425 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2426 case 0: // fall through
2427
2428 // Integer_variable_info {
2429 // u1 tag = ITEM_Integer; /* 1 */
2430 // }
2431 case ITEM_Integer: // fall through
2432
2433 // Float_variable_info {
2434 // u1 tag = ITEM_Float; /* 2 */
2435 // }
2436 case ITEM_Float: // fall through
2437
2438 // Double_variable_info {
2439 // u1 tag = ITEM_Double; /* 3 */
2440 // }
2441 case ITEM_Double: // fall through
2442
2443 // Long_variable_info {
2444 // u1 tag = ITEM_Long; /* 4 */
2445 // }
2446 case ITEM_Long: // fall through
2447
2448 // Null_variable_info {
2449 // u1 tag = ITEM_Null; /* 5 */
2450 // }
2451 case ITEM_Null: // fall through
2452
2453 // UninitializedThis_variable_info {
2454 // u1 tag = ITEM_UninitializedThis; /* 6 */
2455 // }
2456 case ITEM_UninitializedThis:
2457 // nothing more to do for the above tag types
2458 break;
2459
2460 // Object_variable_info {
2461 // u1 tag = ITEM_Object; /* 7 */
2462 // u2 cpool_index;
2463 // }
2464 case ITEM_Object:
2465 {
2466 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2467 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2468 u2 new_cp_index = find_new_index(cpool_index);
2469 if (new_cp_index != 0) {
2470 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2471 ("mapped old cpool_index=%d", cpool_index));
2472 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2473 cpool_index = new_cp_index;
2474 }
2475 stackmap_p_ref += 2;
2476
2477 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2478 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2479 frame_type, cpool_index));
2480 } break;
2481
2482 // Uninitialized_variable_info {
2483 // u1 tag = ITEM_Uninitialized; /* 8 */
2484 // u2 offset;
2485 // }
2486 case ITEM_Uninitialized:
2487 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2488 stackmap_p_ref += 2;
2489 break;
2490
2491 default:
2492 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2493 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2494 ShouldNotReachHere();
2495 break;
2496 } // end switch (tag)
2497 } // end rewrite_cp_refs_in_verification_type_info()
2498
2499
2500 // Change the constant pool associated with klass scratch_class to
2501 // scratch_cp. If shrink is true, then scratch_cp_length elements
2502 // are copied from scratch_cp to a smaller constant pool and the
2503 // smaller constant pool is associated with scratch_class.
2504 void VM_RedefineClasses::set_new_constant_pool(
2505 ClassLoaderData* loader_data,
2506 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2507 int scratch_cp_length, TRAPS) {
2508 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2509
2510 // scratch_cp is a merged constant pool and has enough space for a
2511 // worst case merge situation. We want to associate the minimum
2512 // sized constant pool with the klass to save space.
2513 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
2514 constantPoolHandle smaller_cp(THREAD, cp);
2515
2516 // preserve version() value in the smaller copy
2517 int version = scratch_cp->version();
2518 assert(version != 0, "sanity check");
2519 smaller_cp->set_version(version);
2520
2521 // attach klass to new constant pool
2522 // reference to the cp holder is needed for copy_operands()
2523 smaller_cp->set_pool_holder(scratch_class());
2524
2525 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2526 if (HAS_PENDING_EXCEPTION) {
2527 // Exception is handled in the caller
2528 loader_data->add_to_deallocate_list(smaller_cp());
2529 return;
2530 }
2531 scratch_cp = smaller_cp;
2532
2533 // attach new constant pool to klass
2534 scratch_class->set_constants(scratch_cp());
2535
2536 int i; // for portability
2537
2538 // update each field in klass to use new constant pool indices as needed
2539 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2540 jshort cur_index = fs.name_index();
2541 jshort new_index = find_new_index(cur_index);
2542 if (new_index != 0) {
2543 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2544 ("field-name_index change: %d to %d", cur_index, new_index));
2545 fs.set_name_index(new_index);
2546 }
2547 cur_index = fs.signature_index();
2548 new_index = find_new_index(cur_index);
2549 if (new_index != 0) {
2550 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2551 ("field-signature_index change: %d to %d", cur_index, new_index));
2552 fs.set_signature_index(new_index);
2553 }
2554 cur_index = fs.initval_index();
2555 new_index = find_new_index(cur_index);
2556 if (new_index != 0) {
2557 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2558 ("field-initval_index change: %d to %d", cur_index, new_index));
2559 fs.set_initval_index(new_index);
2560 }
2561 cur_index = fs.generic_signature_index();
2562 new_index = find_new_index(cur_index);
2563 if (new_index != 0) {
2564 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2565 ("field-generic_signature change: %d to %d", cur_index, new_index));
2566 fs.set_generic_signature_index(new_index);
2567 }
2568 } // end for each field
2569
2570 // Update constant pool indices in the inner classes info to use
2571 // new constant indices as needed. The inner classes info is a
2572 // quadruple:
2573 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2574 InnerClassesIterator iter(scratch_class);
2575 for (; !iter.done(); iter.next()) {
2576 int cur_index = iter.inner_class_info_index();
2577 if (cur_index == 0) {
2578 continue; // JVM spec. allows null inner class refs so skip it
2579 }
2580 int new_index = find_new_index(cur_index);
2581 if (new_index != 0) {
2582 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2583 ("inner_class_info change: %d to %d", cur_index, new_index));
2584 iter.set_inner_class_info_index(new_index);
2585 }
2586 cur_index = iter.outer_class_info_index();
2587 new_index = find_new_index(cur_index);
2588 if (new_index != 0) {
2589 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2590 ("outer_class_info change: %d to %d", cur_index, new_index));
2591 iter.set_outer_class_info_index(new_index);
2592 }
2593 cur_index = iter.inner_name_index();
2594 new_index = find_new_index(cur_index);
2595 if (new_index != 0) {
2596 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2597 ("inner_name change: %d to %d", cur_index, new_index));
2598 iter.set_inner_name_index(new_index);
2599 }
2600 } // end for each inner class
2601
2602 // Attach each method in klass to the new constant pool and update
2603 // to use new constant pool indices as needed:
2604 Array<Method*>* methods = scratch_class->methods();
2605 for (i = methods->length() - 1; i >= 0; i--) {
2606 methodHandle method(THREAD, methods->at(i));
2607 method->set_constants(scratch_cp());
2608
2609 int new_index = find_new_index(method->name_index());
2610 if (new_index != 0) {
2611 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2612 ("method-name_index change: %d to %d", method->name_index(),
2613 new_index));
2614 method->set_name_index(new_index);
2615 }
2616 new_index = find_new_index(method->signature_index());
2617 if (new_index != 0) {
2618 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2619 ("method-signature_index change: %d to %d",
2620 method->signature_index(), new_index));
2621 method->set_signature_index(new_index);
2622 }
2623 new_index = find_new_index(method->generic_signature_index());
2624 if (new_index != 0) {
2625 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2626 ("method-generic_signature_index change: %d to %d",
2627 method->generic_signature_index(), new_index));
2628 method->set_generic_signature_index(new_index);
2629 }
2630
2631 // Update constant pool indices in the method's checked exception
2632 // table to use new constant indices as needed.
2633 int cext_length = method->checked_exceptions_length();
2634 if (cext_length > 0) {
2635 CheckedExceptionElement * cext_table =
2636 method->checked_exceptions_start();
2637 for (int j = 0; j < cext_length; j++) {
2638 int cur_index = cext_table[j].class_cp_index;
2639 int new_index = find_new_index(cur_index);
2640 if (new_index != 0) {
2641 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2642 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2643 cext_table[j].class_cp_index = (u2)new_index;
2644 }
2645 } // end for each checked exception table entry
2646 } // end if there are checked exception table entries
2647
2648 // Update each catch type index in the method's exception table
2649 // to use new constant pool indices as needed. The exception table
2650 // holds quadruple entries of the form:
2651 // (beg_bci, end_bci, handler_bci, klass_index)
2652
2653 ExceptionTable ex_table(method());
2654 int ext_length = ex_table.length();
2655
2656 for (int j = 0; j < ext_length; j ++) {
2657 int cur_index = ex_table.catch_type_index(j);
2658 int new_index = find_new_index(cur_index);
2659 if (new_index != 0) {
2660 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2661 ("ext-klass_index change: %d to %d", cur_index, new_index));
2662 ex_table.set_catch_type_index(j, new_index);
2663 }
2664 } // end for each exception table entry
2665
2666 // Update constant pool indices in the method's local variable
2667 // table to use new constant indices as needed. The local variable
2668 // table hold sextuple entries of the form:
2669 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2670 int lvt_length = method->localvariable_table_length();
2671 if (lvt_length > 0) {
2672 LocalVariableTableElement * lv_table =
2673 method->localvariable_table_start();
2674 for (int j = 0; j < lvt_length; j++) {
2675 int cur_index = lv_table[j].name_cp_index;
2676 int new_index = find_new_index(cur_index);
2677 if (new_index != 0) {
2678 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2679 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2680 lv_table[j].name_cp_index = (u2)new_index;
2681 }
2682 cur_index = lv_table[j].descriptor_cp_index;
2683 new_index = find_new_index(cur_index);
2684 if (new_index != 0) {
2685 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2686 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2687 new_index));
2688 lv_table[j].descriptor_cp_index = (u2)new_index;
2689 }
2690 cur_index = lv_table[j].signature_cp_index;
2691 new_index = find_new_index(cur_index);
2692 if (new_index != 0) {
2693 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2694 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2695 lv_table[j].signature_cp_index = (u2)new_index;
2696 }
2697 } // end for each local variable table entry
2698 } // end if there are local variable table entries
2699
2700 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2701 } // end for each method
2702 } // end set_new_constant_pool()
2703
2704
2705 // Unevolving classes may point to methods of the_class directly
2706 // from their constant pool caches, itables, and/or vtables. We
2707 // use the ClassLoaderDataGraph::classes_do() facility and this helper
2708 // to fix up these pointers.
2709
2710 // Adjust cpools and vtables closure
2711 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
2712
2713 // This is a very busy routine. We don't want too much tracing
2714 // printed out.
2715 bool trace_name_printed = false;
2716
2717 // Very noisy: only enable this call if you are trying to determine
2718 // that a specific class gets found by this routine.
2719 // RC_TRACE macro has an embedded ResourceMark
2720 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2721 // ("adjust check: name=%s", k->external_name()));
2722 // trace_name_printed = true;
2723
2724 // If the class being redefined is java.lang.Object, we need to fix all
2725 // array class vtables also
2726 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
2727 k->vtable()->adjust_method_entries(_matching_old_methods,
2728 _matching_new_methods,
2729 _matching_methods_length,
2730 &trace_name_printed);
2731 } else if (k->oop_is_instance()) {
2732 HandleMark hm(_thread);
2733 InstanceKlass *ik = InstanceKlass::cast(k);
2734
2735 // HotSpot specific optimization! HotSpot does not currently
2736 // support delegation from the bootstrap class loader to a
2737 // user-defined class loader. This means that if the bootstrap
2738 // class loader is the initiating class loader, then it will also
2739 // be the defining class loader. This also means that classes
2740 // loaded by the bootstrap class loader cannot refer to classes
2741 // loaded by a user-defined class loader. Note: a user-defined
2742 // class loader can delegate to the bootstrap class loader.
2743 //
2744 // If the current class being redefined has a user-defined class
2745 // loader as its defining class loader, then we can skip all
2746 // classes loaded by the bootstrap class loader.
2747 bool is_user_defined =
2748 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2749 if (is_user_defined && ik->class_loader() == NULL) {
2750 return;
2751 }
2752
2753 // Fix the vtable embedded in the_class and subclasses of the_class,
2754 // if one exists. We discard scratch_class and we don't keep an
2755 // InstanceKlass around to hold obsolete methods so we don't have
2756 // any other InstanceKlass embedded vtables to update. The vtable
2757 // holds the Method*s for virtual (but not final) methods.
2758 // Default methods, or concrete methods in interfaces are stored
2759 // in the vtable, so if an interface changes we need to check
2760 // adjust_method_entries() for every InstanceKlass, which will also
2761 // adjust the default method vtable indices.
2762 // We also need to adjust any default method entries that are
2763 // not yet in the vtable, because the vtable setup is in progress.
2764 // This must be done after we adjust the default_methods and
2765 // default_vtable_indices for methods already in the vtable.
2766 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
2767 || ik->is_subtype_of(_the_class_oop))) {
2768 // ik->vtable() creates a wrapper object; rm cleans it up
2769 ResourceMark rm(_thread);
2770 ik->vtable()->adjust_method_entries(_matching_old_methods,
2771 _matching_new_methods,
2772 _matching_methods_length,
2773 &trace_name_printed);
2774 ik->adjust_default_methods(_matching_old_methods,
2775 _matching_new_methods,
2776 _matching_methods_length,
2777 &trace_name_printed);
2778 }
2779
2780 // If the current class has an itable and we are either redefining an
2781 // interface or if the current class is a subclass of the_class, then
2782 // we potentially have to fix the itable. If we are redefining an
2783 // interface, then we have to call adjust_method_entries() for
2784 // every InstanceKlass that has an itable since there isn't a
2785 // subclass relationship between an interface and an InstanceKlass.
2786 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2787 || ik->is_subclass_of(_the_class_oop))) {
2788 // ik->itable() creates a wrapper object; rm cleans it up
2789 ResourceMark rm(_thread);
2790 ik->itable()->adjust_method_entries(_matching_old_methods,
2791 _matching_new_methods,
2792 _matching_methods_length,
2793 &trace_name_printed);
2794 }
2795
2796 // The constant pools in other classes (other_cp) can refer to
2797 // methods in the_class. We have to update method information in
2798 // other_cp's cache. If other_cp has a previous version, then we
2799 // have to repeat the process for each previous version. The
2800 // constant pool cache holds the Method*s for non-virtual
2801 // methods and for virtual, final methods.
2802 //
2803 // Special case: if the current class is the_class, then new_cp
2804 // has already been attached to the_class and old_cp has already
2805 // been added as a previous version. The new_cp doesn't have any
2806 // cached references to old methods so it doesn't need to be
2807 // updated. We can simply start with the previous version(s) in
2808 // that case.
2809 constantPoolHandle other_cp;
2810 ConstantPoolCache* cp_cache;
2811
2812 if (ik != _the_class_oop) {
2813 // this klass' constant pool cache may need adjustment
2814 other_cp = constantPoolHandle(ik->constants());
2815 cp_cache = other_cp->cache();
2816 if (cp_cache != NULL) {
2817 cp_cache->adjust_method_entries(_matching_old_methods,
2818 _matching_new_methods,
2819 _matching_methods_length,
2820 &trace_name_printed);
2821 }
2822 }
2823
2824 // the previous versions' constant pool caches may need adjustment
2825 PreviousVersionWalker pvw(_thread, ik);
2826 for (PreviousVersionNode * pv_node = pvw.next_previous_version();
2827 pv_node != NULL; pv_node = pvw.next_previous_version()) {
2828 other_cp = pv_node->prev_constant_pool();
2829 cp_cache = other_cp->cache();
2830 if (cp_cache != NULL) {
2831 cp_cache->adjust_method_entries(_matching_old_methods,
2832 _matching_new_methods,
2833 _matching_methods_length,
2834 &trace_name_printed);
2835 }
2836 }
2837 }
2838 }
2839
2840 void VM_RedefineClasses::update_jmethod_ids() {
2841 for (int j = 0; j < _matching_methods_length; ++j) {
2842 Method* old_method = _matching_old_methods[j];
2843 jmethodID jmid = old_method->find_jmethod_id_or_null();
2844 if (jmid != NULL) {
2845 // There is a jmethodID, change it to point to the new method
2846 methodHandle new_method_h(_matching_new_methods[j]);
2847 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2848 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2849 "should be replaced");
2850 }
2851 }
2852 }
2853
2854 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2855 BitMap *emcp_methods, int * emcp_method_count_p) {
2856 *emcp_method_count_p = 0;
2857 int obsolete_count = 0;
2858 int old_index = 0;
2859 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2860 Method* old_method = _matching_old_methods[j];
2861 Method* new_method = _matching_new_methods[j];
2862 Method* old_array_method;
2863
2864 // Maintain an old_index into the _old_methods array by skipping
2865 // deleted methods
2866 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2867 ++old_index;
2868 }
2869
2870 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2871 // The EMCP definition from JSR-163 requires the bytecodes to be
2872 // the same with the exception of constant pool indices which may
2873 // differ. However, the constants referred to by those indices
2874 // must be the same.
2875 //
2876 // We use methods_EMCP() for comparison since constant pool
2877 // merging can remove duplicate constant pool entries that were
2878 // present in the old method and removed from the rewritten new
2879 // method. A faster binary comparison function would consider the
2880 // old and new methods to be different when they are actually
2881 // EMCP.
2882 //
2883 // The old and new methods are EMCP and you would think that we
2884 // could get rid of one of them here and now and save some space.
2885 // However, the concept of EMCP only considers the bytecodes and
2886 // the constant pool entries in the comparison. Other things,
2887 // e.g., the line number table (LNT) or the local variable table
2888 // (LVT) don't count in the comparison. So the new (and EMCP)
2889 // method can have a new LNT that we need so we can't just
2890 // overwrite the new method with the old method.
2891 //
2892 // When this routine is called, we have already attached the new
2893 // methods to the_class so the old methods are effectively
2894 // overwritten. However, if an old method is still executing,
2895 // then the old method cannot be collected until sometime after
2896 // the old method call has returned. So the overwriting of old
2897 // methods by new methods will save us space except for those
2898 // (hopefully few) old methods that are still executing.
2899 //
2900 // A method refers to a ConstMethod* and this presents another
2901 // possible avenue to space savings. The ConstMethod* in the
2902 // new method contains possibly new attributes (LNT, LVT, etc).
2903 // At first glance, it seems possible to save space by replacing
2904 // the ConstMethod* in the old method with the ConstMethod*
2905 // from the new method. The old and new methods would share the
2906 // same ConstMethod* and we would save the space occupied by
2907 // the old ConstMethod*. However, the ConstMethod* contains
2908 // a back reference to the containing method. Sharing the
2909 // ConstMethod* between two methods could lead to confusion in
2910 // the code that uses the back reference. This would lead to
2911 // brittle code that could be broken in non-obvious ways now or
2912 // in the future.
2913 //
2914 // Another possibility is to copy the ConstMethod* from the new
2915 // method to the old method and then overwrite the new method with
2916 // the old method. Since the ConstMethod* contains the bytecodes
2917 // for the method embedded in the oop, this option would change
2918 // the bytecodes out from under any threads executing the old
2919 // method and make the thread's bcp invalid. Since EMCP requires
2920 // that the bytecodes be the same modulo constant pool indices, it
2921 // is straight forward to compute the correct new bcp in the new
2922 // ConstMethod* from the old bcp in the old ConstMethod*. The
2923 // time consuming part would be searching all the frames in all
2924 // of the threads to find all of the calls to the old method.
2925 //
2926 // It looks like we will have to live with the limited savings
2927 // that we get from effectively overwriting the old methods
2928 // when the new methods are attached to the_class.
2929
2930 // track which methods are EMCP for add_previous_version() call
2931 emcp_methods->set_bit(old_index);
2932 (*emcp_method_count_p)++;
2933
2934 // An EMCP method is _not_ obsolete. An obsolete method has a
2935 // different jmethodID than the current method. An EMCP method
2936 // has the same jmethodID as the current method. Having the
2937 // same jmethodID for all EMCP versions of a method allows for
2938 // a consistent view of the EMCP methods regardless of which
2939 // EMCP method you happen to have in hand. For example, a
2940 // breakpoint set in one EMCP method will work for all EMCP
2941 // versions of the method including the current one.
2942 } else {
2943 // mark obsolete methods as such
2944 old_method->set_is_obsolete();
2945 obsolete_count++;
2946
2947 // obsolete methods need a unique idnum so they become new entries in
2948 // the jmethodID cache in InstanceKlass
2949 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2950 if (num != ConstMethod::UNSET_IDNUM) {
2951 old_method->set_method_idnum(num);
2952 }
2953
2954 // With tracing we try not to "yack" too much. The position of
2955 // this trace assumes there are fewer obsolete methods than
2956 // EMCP methods.
2957 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2958 old_method->name()->as_C_string(),
2959 old_method->signature()->as_C_string()));
2960 }
2961 old_method->set_is_old();
2962 }
2963 for (int i = 0; i < _deleted_methods_length; ++i) {
2964 Method* old_method = _deleted_methods[i];
2965
2966 assert(!old_method->has_vtable_index(),
2967 "cannot delete methods with vtable entries");;
2968
2969 // Mark all deleted methods as old and obsolete
2970 old_method->set_is_old();
2971 old_method->set_is_obsolete();
2972 ++obsolete_count;
2973 // With tracing we try not to "yack" too much. The position of
2974 // this trace assumes there are fewer obsolete methods than
2975 // EMCP methods.
2976 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2977 old_method->name()->as_C_string(),
2978 old_method->signature()->as_C_string()));
2979 }
2980 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2981 "sanity check");
2982 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2983 obsolete_count));
2984 }
2985
2986 // This internal class transfers the native function registration from old methods
2987 // to new methods. It is designed to handle both the simple case of unchanged
2988 // native methods and the complex cases of native method prefixes being added and/or
2989 // removed.
2990 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2991 //
2992 // This class is used after the new methods have been installed in "the_class".
2993 //
2994 // So, for example, the following must be handled. Where 'm' is a method and
2995 // a number followed by an underscore is a prefix.
2996 //
2997 // Old Name New Name
2998 // Simple transfer to new method m -> m
2999 // Add prefix m -> 1_m
3000 // Remove prefix 1_m -> m
3001 // Simultaneous add of prefixes m -> 3_2_1_m
3002 // Simultaneous removal of prefixes 3_2_1_m -> m
3003 // Simultaneous add and remove 1_m -> 2_m
3004 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3005 //
3006 class TransferNativeFunctionRegistration {
3007 private:
3008 instanceKlassHandle the_class;
3009 int prefix_count;
3010 char** prefixes;
3011
3012 // Recursively search the binary tree of possibly prefixed method names.
3013 // Iteration could be used if all agents were well behaved. Full tree walk is
3014 // more resilent to agents not cleaning up intermediate methods.
3015 // Branch at each depth in the binary tree is:
3016 // (1) without the prefix.
3017 // (2) with the prefix.
3018 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3019 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3020 Symbol* signature) {
3021 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3022 if (name_symbol != NULL) {
3023 Method* method = the_class()->lookup_method(name_symbol, signature);
3024 if (method != NULL) {
3025 // Even if prefixed, intermediate methods must exist.
3026 if (method->is_native()) {
3027 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3028 return method;
3029 }
3030 if (depth < prefix_count) {
3031 // Try applying further prefixes (other than this one).
3032 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3033 if (method != NULL) {
3034 return method; // found
3035 }
3036
3037 // Try adding this prefix to the method name and see if it matches
3038 // another method name.
3039 char* prefix = prefixes[depth];
3040 size_t prefix_len = strlen(prefix);
3041 size_t trial_len = name_len + prefix_len;
3042 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3043 strcpy(trial_name_str, prefix);
3044 strcat(trial_name_str, name_str);
3045 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3046 signature);
3047 if (method != NULL) {
3048 // If found along this branch, it was prefixed, mark as such
3049 method->set_is_prefixed_native();
3050 return method; // found
3051 }
3052 }
3053 }
3054 }
3055 return NULL; // This whole branch bore nothing
3056 }
3057
3058 // Return the method name with old prefixes stripped away.
3059 char* method_name_without_prefixes(Method* method) {
3060 Symbol* name = method->name();
3061 char* name_str = name->as_utf8();
3062
3063 // Old prefixing may be defunct, strip prefixes, if any.
3064 for (int i = prefix_count-1; i >= 0; i--) {
3065 char* prefix = prefixes[i];
3066 size_t prefix_len = strlen(prefix);
3067 if (strncmp(prefix, name_str, prefix_len) == 0) {
3068 name_str += prefix_len;
3069 }
3070 }
3071 return name_str;
3072 }
3073
3074 // Strip any prefixes off the old native method, then try to find a
3075 // (possibly prefixed) new native that matches it.
3076 Method* strip_and_search_for_new_native(Method* method) {
3077 ResourceMark rm;
3078 char* name_str = method_name_without_prefixes(method);
3079 return search_prefix_name_space(0, name_str, strlen(name_str),
3080 method->signature());
3081 }
3082
3083 public:
3084
3085 // Construct a native method transfer processor for this class.
3086 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3087 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3088
3089 the_class = _the_class;
3090 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3091 }
3092
3093 // Attempt to transfer any of the old or deleted methods that are native
3094 void transfer_registrations(Method** old_methods, int methods_length) {
3095 for (int j = 0; j < methods_length; j++) {
3096 Method* old_method = old_methods[j];
3097
3098 if (old_method->is_native() && old_method->has_native_function()) {
3099 Method* new_method = strip_and_search_for_new_native(old_method);
3100 if (new_method != NULL) {
3101 // Actually set the native function in the new method.
3102 // Redefine does not send events (except CFLH), certainly not this
3103 // behind the scenes re-registration.
3104 new_method->set_native_function(old_method->native_function(),
3105 !Method::native_bind_event_is_interesting);
3106 }
3107 }
3108 }
3109 }
3110 };
3111
3112 // Don't lose the association between a native method and its JNI function.
3113 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3114 TransferNativeFunctionRegistration transfer(the_class);
3115 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3116 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3117 }
3118
3119 // Deoptimize all compiled code that depends on this class.
3120 //
3121 // If the can_redefine_classes capability is obtained in the onload
3122 // phase then the compiler has recorded all dependencies from startup.
3123 // In that case we need only deoptimize and throw away all compiled code
3124 // that depends on the class.
3125 //
3126 // If can_redefine_classes is obtained sometime after the onload
3127 // phase then the dependency information may be incomplete. In that case
3128 // the first call to RedefineClasses causes all compiled code to be
3129 // thrown away. As can_redefine_classes has been obtained then
3130 // all future compilations will record dependencies so second and
3131 // subsequent calls to RedefineClasses need only throw away code
3132 // that depends on the class.
3133 //
3134 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3135 assert_locked_or_safepoint(Compile_lock);
3136
3137 // All dependencies have been recorded from startup or this is a second or
3138 // subsequent use of RedefineClasses
3139 if (JvmtiExport::all_dependencies_are_recorded()) {
3140 Universe::flush_evol_dependents_on(k_h);
3141 } else {
3142 CodeCache::mark_all_nmethods_for_deoptimization();
3143
3144 ResourceMark rm(THREAD);
3145 DeoptimizationMarker dm;
3146
3147 // Deoptimize all activations depending on marked nmethods
3148 Deoptimization::deoptimize_dependents();
3149
3150 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3151 CodeCache::make_marked_nmethods_not_entrant();
3152
3153 // From now on we know that the dependency information is complete
3154 JvmtiExport::set_all_dependencies_are_recorded(true);
3155 }
3156 }
3157
3158 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3159 Method* old_method;
3160 Method* new_method;
3161
3162 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3163 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3164 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3165 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3166
3167 _matching_methods_length = 0;
3168 _deleted_methods_length = 0;
3169 _added_methods_length = 0;
3170
3171 int nj = 0;
3172 int oj = 0;
3173 while (true) {
3174 if (oj >= _old_methods->length()) {
3175 if (nj >= _new_methods->length()) {
3176 break; // we've looked at everything, done
3177 }
3178 // New method at the end
3179 new_method = _new_methods->at(nj);
3180 _added_methods[_added_methods_length++] = new_method;
3181 ++nj;
3182 } else if (nj >= _new_methods->length()) {
3183 // Old method, at the end, is deleted
3184 old_method = _old_methods->at(oj);
3185 _deleted_methods[_deleted_methods_length++] = old_method;
3186 ++oj;
3187 } else {
3188 old_method = _old_methods->at(oj);
3189 new_method = _new_methods->at(nj);
3190 if (old_method->name() == new_method->name()) {
3191 if (old_method->signature() == new_method->signature()) {
3192 _matching_old_methods[_matching_methods_length ] = old_method;
3193 _matching_new_methods[_matching_methods_length++] = new_method;
3194 ++nj;
3195 ++oj;
3196 } else {
3197 // added overloaded have already been moved to the end,
3198 // so this is a deleted overloaded method
3199 _deleted_methods[_deleted_methods_length++] = old_method;
3200 ++oj;
3201 }
3202 } else { // names don't match
3203 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3204 // new method
3205 _added_methods[_added_methods_length++] = new_method;
3206 ++nj;
3207 } else {
3208 // deleted method
3209 _deleted_methods[_deleted_methods_length++] = old_method;
3210 ++oj;
3211 }
3212 }
3213 }
3214 }
3215 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3216 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3217 }
3218
3219
3220 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3221 instanceKlassHandle scratch_class) {
3222 // Since there is currently no rewriting of type annotations indexes
3223 // into the CP, we null out type annotations on scratch_class before
3224 // we swap annotations with the_class rather than facing the
3225 // possibility of shipping annotations with broken indexes to
3226 // Java-land.
3227 ClassLoaderData* loader_data = scratch_class->class_loader_data();
3228 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
3229 if (new_class_type_annotations != NULL) {
3230 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
3231 scratch_class->annotations()->set_class_type_annotations(NULL);
3232 }
3233 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
3234 if (new_field_type_annotations != NULL) {
3235 Annotations::free_contents(loader_data, new_field_type_annotations);
3236 scratch_class->annotations()->set_fields_type_annotations(NULL);
3237 }
3238
3239 // Swap annotation fields values
3240 Annotations* old_annotations = the_class->annotations();
3241 the_class->set_annotations(scratch_class->annotations());
3242 scratch_class->set_annotations(old_annotations);
3243 }
3244
3245
3246 // Install the redefinition of a class:
3247 // - house keeping (flushing breakpoints and caches, deoptimizing
3248 // dependent compiled code)
3249 // - replacing parts in the_class with parts from scratch_class
3250 // - adding a weak reference to track the obsolete but interesting
3251 // parts of the_class
3252 // - adjusting constant pool caches and vtables in other classes
3253 // that refer to methods in the_class. These adjustments use the
3254 // ClassLoaderDataGraph::classes_do() facility which only allows
3255 // a helper method to be specified. The interesting parameters
3256 // that we would like to pass to the helper method are saved in
3257 // static global fields in the VM operation.
3258 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3259 Klass* scratch_class_oop, TRAPS) {
3260
3261 HandleMark hm(THREAD); // make sure handles from this call are freed
3262 RC_TIMER_START(_timer_rsc_phase1);
3263
3264 instanceKlassHandle scratch_class(scratch_class_oop);
3265
3266 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3267 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3268 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3269
3270 // Remove all breakpoints in methods of this class
3271 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3272 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3273
3274 // Deoptimize all compiled code that depends on this class
3275 flush_dependent_code(the_class, THREAD);
3276
3277 _old_methods = the_class->methods();
3278 _new_methods = scratch_class->methods();
3279 _the_class_oop = the_class_oop;
3280 compute_added_deleted_matching_methods();
3281 update_jmethod_ids();
3282
3283 // Attach new constant pool to the original klass. The original
3284 // klass still refers to the old constant pool (for now).
3285 scratch_class->constants()->set_pool_holder(the_class());
3286
3287 #if 0
3288 // In theory, with constant pool merging in place we should be able
3289 // to save space by using the new, merged constant pool in place of
3290 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3291 // the klass version we are replacing now and any constant pool(s) in
3292 // previous versions of klass. Nice theory, doesn't work in practice.
3293 // When this code is enabled, even simple programs throw NullPointer
3294 // exceptions. I'm guessing that this is caused by some constant pool
3295 // cache difference between the new, merged constant pool and the
3296 // constant pool that was just being used by the klass. I'm keeping
3297 // this code around to archive the idea, but the code has to remain
3298 // disabled for now.
3299
3300 // Attach each old method to the new constant pool. This can be
3301 // done here since we are past the bytecode verification and
3302 // constant pool optimization phases.
3303 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3304 Method* method = _old_methods->at(i);
3305 method->set_constants(scratch_class->constants());
3306 }
3307
3308 {
3309 // walk all previous versions of the klass
3310 InstanceKlass *ik = (InstanceKlass *)the_class();
3311 PreviousVersionWalker pvw(ik);
3312 instanceKlassHandle ikh;
3313 do {
3314 ikh = pvw.next_previous_version();
3315 if (!ikh.is_null()) {
3316 ik = ikh();
3317
3318 // attach previous version of klass to the new constant pool
3319 ik->set_constants(scratch_class->constants());
3320
3321 // Attach each method in the previous version of klass to the
3322 // new constant pool
3323 Array<Method*>* prev_methods = ik->methods();
3324 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3325 Method* method = prev_methods->at(i);
3326 method->set_constants(scratch_class->constants());
3327 }
3328 }
3329 } while (!ikh.is_null());
3330 }
3331 #endif
3332
3333 // Replace methods and constantpool
3334 the_class->set_methods(_new_methods);
3335 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3336 // and to be able to undo operation easily.
3337
3338 ConstantPool* old_constants = the_class->constants();
3339 the_class->set_constants(scratch_class->constants());
3340 scratch_class->set_constants(old_constants); // See the previous comment.
3341 #if 0
3342 // We are swapping the guts of "the new class" with the guts of "the
3343 // class". Since the old constant pool has just been attached to "the
3344 // new class", it seems logical to set the pool holder in the old
3345 // constant pool also. However, doing this will change the observable
3346 // class hierarchy for any old methods that are still executing. A
3347 // method can query the identity of its "holder" and this query uses
3348 // the method's constant pool link to find the holder. The change in
3349 // holding class from "the class" to "the new class" can confuse
3350 // things.
3351 //
3352 // Setting the old constant pool's holder will also cause
3353 // verification done during vtable initialization below to fail.
3354 // During vtable initialization, the vtable's class is verified to be
3355 // a subtype of the method's holder. The vtable's class is "the
3356 // class" and the method's holder is gotten from the constant pool
3357 // link in the method itself. For "the class"'s directly implemented
3358 // methods, the method holder is "the class" itself (as gotten from
3359 // the new constant pool). The check works fine in this case. The
3360 // check also works fine for methods inherited from super classes.
3361 //
3362 // Miranda methods are a little more complicated. A miranda method is
3363 // provided by an interface when the class implementing the interface
3364 // does not provide its own method. These interfaces are implemented
3365 // internally as an InstanceKlass. These special instanceKlasses
3366 // share the constant pool of the class that "implements" the
3367 // interface. By sharing the constant pool, the method holder of a
3368 // miranda method is the class that "implements" the interface. In a
3369 // non-redefine situation, the subtype check works fine. However, if
3370 // the old constant pool's pool holder is modified, then the check
3371 // fails because there is no class hierarchy relationship between the
3372 // vtable's class and "the new class".
3373
3374 old_constants->set_pool_holder(scratch_class());
3375 #endif
3376
3377 // track which methods are EMCP for add_previous_version() call below
3378 BitMap emcp_methods(_old_methods->length());
3379 int emcp_method_count = 0;
3380 emcp_methods.clear(); // clears 0..(length() - 1)
3381 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3382 transfer_old_native_function_registrations(the_class);
3383
3384 // The class file bytes from before any retransformable agents mucked
3385 // with them was cached on the scratch class, move to the_class.
3386 // Note: we still want to do this if nothing needed caching since it
3387 // should get cleared in the_class too.
3388 if (the_class->get_cached_class_file_bytes() == 0) {
3389 // the_class doesn't have a cache yet so copy it
3390 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3391 }
3392 #ifndef PRODUCT
3393 else {
3394 assert(the_class->get_cached_class_file_bytes() ==
3395 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3396 assert(the_class->get_cached_class_file_len() ==
3397 scratch_class->get_cached_class_file_len(), "cache lens must match");
3398 }
3399 #endif
3400
3401 // NULL out in scratch class to not delete twice. The class to be redefined
3402 // always owns these bytes.
3403 scratch_class->set_cached_class_file(NULL);
3404
3405 // Replace inner_classes
3406 Array<u2>* old_inner_classes = the_class->inner_classes();
3407 the_class->set_inner_classes(scratch_class->inner_classes());
3408 scratch_class->set_inner_classes(old_inner_classes);
3409
3410 // Initialize the vtable and interface table after
3411 // methods have been rewritten
3412 {
3413 ResourceMark rm(THREAD);
3414 // no exception should happen here since we explicitly
3415 // do not check loader constraints.
3416 // compare_and_normalize_class_versions has already checked:
3417 // - classloaders unchanged, signatures unchanged
3418 // - all instanceKlasses for redefined classes reused & contents updated
3419 the_class->vtable()->initialize_vtable(false, THREAD);
3420 the_class->itable()->initialize_itable(false, THREAD);
3421 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3422 }
3423
3424 // Leave arrays of jmethodIDs and itable index cache unchanged
3425
3426 // Copy the "source file name" attribute from new class version
3427 the_class->set_source_file_name_index(
3428 scratch_class->source_file_name_index());
3429
3430 // Copy the "source debug extension" attribute from new class version
3431 the_class->set_source_debug_extension(
3432 scratch_class->source_debug_extension(),
3433 scratch_class->source_debug_extension() == NULL ? 0 :
3434 (int)strlen(scratch_class->source_debug_extension()));
3435
3436 // Use of javac -g could be different in the old and the new
3437 if (scratch_class->access_flags().has_localvariable_table() !=
3438 the_class->access_flags().has_localvariable_table()) {
3439
3440 AccessFlags flags = the_class->access_flags();
3441 if (scratch_class->access_flags().has_localvariable_table()) {
3442 flags.set_has_localvariable_table();
3443 } else {
3444 flags.clear_has_localvariable_table();
3445 }
3446 the_class->set_access_flags(flags);
3447 }
3448
3449 swap_annotations(the_class, scratch_class);
3450
3451 // Replace minor version number of class file
3452 u2 old_minor_version = the_class->minor_version();
3453 the_class->set_minor_version(scratch_class->minor_version());
3454 scratch_class->set_minor_version(old_minor_version);
3455
3456 // Replace major version number of class file
3457 u2 old_major_version = the_class->major_version();
3458 the_class->set_major_version(scratch_class->major_version());
3459 scratch_class->set_major_version(old_major_version);
3460
3461 // Replace CP indexes for class and name+type of enclosing method
3462 u2 old_class_idx = the_class->enclosing_method_class_index();
3463 u2 old_method_idx = the_class->enclosing_method_method_index();
3464 the_class->set_enclosing_method_indices(
3465 scratch_class->enclosing_method_class_index(),
3466 scratch_class->enclosing_method_method_index());
3467 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3468
3469 // keep track of previous versions of this class
3470 the_class->add_previous_version(scratch_class, &emcp_methods,
3471 emcp_method_count);
3472
3473 RC_TIMER_STOP(_timer_rsc_phase1);
3474 RC_TIMER_START(_timer_rsc_phase2);
3475
3476 // Adjust constantpool caches and vtables for all classes
3477 // that reference methods of the evolved class.
3478 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
3479 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
3480
3481 // JSR-292 support
3482 MemberNameTable* mnt = the_class->member_names();
3483 if (mnt != NULL) {
3484 bool trace_name_printed = false;
3485 mnt->adjust_method_entries(_matching_old_methods,
3486 _matching_new_methods,
3487 _matching_methods_length,
3488 &trace_name_printed);
3489 }
3490
3491 // Fix Resolution Error table also to remove old constant pools
3492 SystemDictionary::delete_resolution_error(old_constants);
3493
3494 if (the_class->oop_map_cache() != NULL) {
3495 // Flush references to any obsolete methods from the oop map cache
3496 // so that obsolete methods are not pinned.
3497 the_class->oop_map_cache()->flush_obsolete_entries();
3498 }
3499
3500 // increment the classRedefinedCount field in the_class and in any
3501 // direct and indirect subclasses of the_class
3502 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3503
3504 // RC_TRACE macro has an embedded ResourceMark
3505 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3506 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3507 the_class->external_name(),
3508 java_lang_Class::classRedefinedCount(the_class_mirror),
3509 os::available_memory() >> 10));
3510
3511 RC_TIMER_STOP(_timer_rsc_phase2);
3512 } // end redefine_single_class()
3513
3514
3515 // Increment the classRedefinedCount field in the specific InstanceKlass
3516 // and in all direct and indirect subclasses.
3517 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3518 oop class_mirror = ik->java_mirror();
3519 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3520 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3521 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3522
3523 if (class_oop != _the_class_oop) {
3524 // _the_class_oop count is printed at end of redefine_single_class()
3525 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3526 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3527 }
3528
3529 for (Klass *subk = ik->subklass(); subk != NULL;
3530 subk = subk->next_sibling()) {
3531 if (subk->oop_is_instance()) {
3532 // Only update instanceKlasses
3533 InstanceKlass *subik = (InstanceKlass*)subk;
3534 // recursively do subclasses of the current subclass
3535 increment_class_counter(subik, THREAD);
3536 }
3537 }
3538 }
3539
3540 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
3541 bool no_old_methods = true; // be optimistic
3542
3543 // Both array and instance classes have vtables.
3544 // a vtable should never contain old or obsolete methods
3545 ResourceMark rm(_thread);
3546 if (k->vtable_length() > 0 &&
3547 !k->vtable()->check_no_old_or_obsolete_entries()) {
3548 if (RC_TRACE_ENABLED(0x00004000)) {
3549 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3550 ("klassVtable::check_no_old_or_obsolete_entries failure"
3551 " -- OLD or OBSOLETE method found -- class: %s",
3552 k->signature_name()));
3553 k->vtable()->dump_vtable();
3554 }
3555 no_old_methods = false;
3556 }
3557
3558 if (k->oop_is_instance()) {
3559 HandleMark hm(_thread);
3560 InstanceKlass *ik = InstanceKlass::cast(k);
3561
3562 // an itable should never contain old or obsolete methods
3563 if (ik->itable_length() > 0 &&
3564 !ik->itable()->check_no_old_or_obsolete_entries()) {
3565 if (RC_TRACE_ENABLED(0x00004000)) {
3566 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3567 ("klassItable::check_no_old_or_obsolete_entries failure"
3568 " -- OLD or OBSOLETE method found -- class: %s",
3569 ik->signature_name()));
3570 ik->itable()->dump_itable();
3571 }
3572 no_old_methods = false;
3573 }
3574
3575 // the constant pool cache should never contain old or obsolete methods
3576 if (ik->constants() != NULL &&
3577 ik->constants()->cache() != NULL &&
3578 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
3579 if (RC_TRACE_ENABLED(0x00004000)) {
3580 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3581 ("cp-cache::check_no_old_or_obsolete_entries failure"
3582 " -- OLD or OBSOLETE method found -- class: %s",
3583 ik->signature_name()));
3584 ik->constants()->cache()->dump_cache();
3585 }
3586 no_old_methods = false;
3587 }
3588 }
3589
3590 // print and fail guarantee if old methods are found.
3591 if (!no_old_methods) {
3592 if (RC_TRACE_ENABLED(0x00004000)) {
3593 dump_methods();
3594 } else {
3595 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
3596 "to see more info about the following guarantee() failure.");
3597 }
3598 guarantee(false, "OLD and/or OBSOLETE method(s) found");
3599 }
3600 }
3601
3602
3603 void VM_RedefineClasses::dump_methods() {
3604 int j;
3605 RC_TRACE(0x00004000, ("_old_methods --"));
3606 for (j = 0; j < _old_methods->length(); ++j) {
3607 Method* m = _old_methods->at(j);
3608 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3609 m->access_flags().print_on(tty);
3610 tty->print(" -- ");
3611 m->print_name(tty);
3612 tty->cr();
3613 }
3614 RC_TRACE(0x00004000, ("_new_methods --"));
3615 for (j = 0; j < _new_methods->length(); ++j) {
3616 Method* m = _new_methods->at(j);
3617 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3618 m->access_flags().print_on(tty);
3619 tty->print(" -- ");
3620 m->print_name(tty);
3621 tty->cr();
3622 }
3623 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
3624 for (j = 0; j < _matching_methods_length; ++j) {
3625 Method* m = _matching_old_methods[j];
3626 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3627 m->access_flags().print_on(tty);
3628 tty->print(" -- ");
3629 m->print_name(tty);
3630 tty->cr();
3631 m = _matching_new_methods[j];
3632 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
3633 m->access_flags().print_on(tty);
3634 tty->cr();
3635 }
3636 RC_TRACE(0x00004000, ("_deleted_methods --"));
3637 for (j = 0; j < _deleted_methods_length; ++j) {
3638 Method* m = _deleted_methods[j];
3639 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3640 m->access_flags().print_on(tty);
3641 tty->print(" -- ");
3642 m->print_name(tty);
3643 tty->cr();
3644 }
3645 RC_TRACE(0x00004000, ("_added_methods --"));
3646 for (j = 0; j < _added_methods_length; ++j) {
3647 Method* m = _added_methods[j];
3648 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3649 m->access_flags().print_on(tty);
3650 tty->print(" -- ");
3651 m->print_name(tty);
3652 tty->cr();
3653 }
3654 }