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 (res != JVMTI_ERROR_NONE) {
1076 return res;
1077 }
1078
1079 if (VerifyMergedCPBytecodes) {
1080 // verify what we have done during constant pool merging
1081 {
1082 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1083 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1084 }
1085
1086 if (HAS_PENDING_EXCEPTION) {
1087 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1088 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1089 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1090 ("verify_byte_codes post merge-CP exception: '%s'",
1091 ex_name->as_C_string()));
1092 CLEAR_PENDING_EXCEPTION;
1093 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1094 return JVMTI_ERROR_OUT_OF_MEMORY;
1095 } else {
1096 // tell the caller that constant pool merging screwed up
1097 return JVMTI_ERROR_INTERNAL;
1098 }
1099 }
1100 }
1101
1102 Rewriter::rewrite(scratch_class, THREAD);
1103 if (!HAS_PENDING_EXCEPTION) {
1104 scratch_class->link_methods(THREAD);
1105 }
1106 if (HAS_PENDING_EXCEPTION) {
1107 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1108 CLEAR_PENDING_EXCEPTION;
1109 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1110 return JVMTI_ERROR_OUT_OF_MEMORY;
1111 } else {
1112 return JVMTI_ERROR_INTERNAL;
1113 }
1114 }
1115
1116 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1117 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1118 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1119 the_class->external_name(), os::available_memory() >> 10));
1120 }
1121
1122 return JVMTI_ERROR_NONE;
1123 }
1124
1125
1126 // Map old_index to new_index as needed. scratch_cp is only needed
1127 // for RC_TRACE() calls.
1128 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1129 int old_index, int new_index) {
1130 if (find_new_index(old_index) != 0) {
1131 // old_index is already mapped
1132 return;
1133 }
1134
1135 if (old_index == new_index) {
1136 // no mapping is needed
1137 return;
1138 }
1139
1140 _index_map_p->at_put(old_index, new_index);
1141 _index_map_count++;
1142
1143 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1144 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1145 } // end map_index()
1146
1147
1148 // Map old_index to new_index as needed.
1149 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1150 if (find_new_operand_index(old_index) != -1) {
1151 // old_index is already mapped
1152 return;
1153 }
1154
1155 if (old_index == new_index) {
1156 // no mapping is needed
1157 return;
1158 }
1159
1160 _operands_index_map_p->at_put(old_index, new_index);
1161 _operands_index_map_count++;
1162
1163 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1164 } // end map_index()
1165
1166
1167 // Merge old_cp and scratch_cp and return the results of the merge via
1168 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1169 // merge_cp_length_p. The entries in old_cp occupy the same locations
1170 // in *merge_cp_p. Also creates a map of indices from entries in
1171 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1172 // entries are only created for entries in scratch_cp that occupy a
1173 // different location in *merged_cp_p.
1174 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1175 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1176 int *merge_cp_length_p, TRAPS) {
1177
1178 if (merge_cp_p == NULL) {
1179 assert(false, "caller must provide scratch constantPool");
1180 return false; // robustness
1181 }
1182 if (merge_cp_length_p == NULL) {
1183 assert(false, "caller must provide scratch CP length");
1184 return false; // robustness
1185 }
1186 // Worst case we need old_cp->length() + scratch_cp()->length(),
1187 // but the caller might be smart so make sure we have at least
1188 // the minimum.
1189 if ((*merge_cp_p)->length() < old_cp->length()) {
1190 assert(false, "merge area too small");
1191 return false; // robustness
1192 }
1193
1194 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1195 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1196 scratch_cp->length()));
1197
1198 {
1199 // Pass 0:
1200 // The old_cp is copied to *merge_cp_p; this means that any code
1201 // using old_cp does not have to change. This work looks like a
1202 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1203 // handle one special case:
1204 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1205 // This will make verification happy.
1206
1207 int old_i; // index into old_cp
1208
1209 // index zero (0) is not used in constantPools
1210 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1211 // leave debugging crumb
1212 jbyte old_tag = old_cp->tag_at(old_i).value();
1213 switch (old_tag) {
1214 case JVM_CONSTANT_Class:
1215 case JVM_CONSTANT_UnresolvedClass:
1216 // revert the copy to JVM_CONSTANT_UnresolvedClass
1217 // May be resolving while calling this so do the same for
1218 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1219 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1220 old_cp->klass_name_at(old_i));
1221 break;
1222
1223 case JVM_CONSTANT_Double:
1224 case JVM_CONSTANT_Long:
1225 // just copy the entry to *merge_cp_p, but double and long take
1226 // two constant pool entries
1227 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1228 old_i++;
1229 break;
1230
1231 default:
1232 // just copy the entry to *merge_cp_p
1233 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1234 break;
1235 }
1236 } // end for each old_cp entry
1237
1238 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1239 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1240
1241 // We don't need to sanity check that *merge_cp_length_p is within
1242 // *merge_cp_p bounds since we have the minimum on-entry check above.
1243 (*merge_cp_length_p) = old_i;
1244 }
1245
1246 // merge_cp_len should be the same as old_cp->length() at this point
1247 // so this trace message is really a "warm-and-breathing" message.
1248 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1249 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1250
1251 int scratch_i; // index into scratch_cp
1252 {
1253 // Pass 1a:
1254 // Compare scratch_cp entries to the old_cp entries that we have
1255 // already copied to *merge_cp_p. In this pass, we are eliminating
1256 // exact duplicates (matching entry at same index) so we only
1257 // compare entries in the common indice range.
1258 int increment = 1;
1259 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1260 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1261 switch (scratch_cp->tag_at(scratch_i).value()) {
1262 case JVM_CONSTANT_Double:
1263 case JVM_CONSTANT_Long:
1264 // double and long take two constant pool entries
1265 increment = 2;
1266 break;
1267
1268 default:
1269 increment = 1;
1270 break;
1271 }
1272
1273 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1274 scratch_i, CHECK_0);
1275 if (match) {
1276 // found a match at the same index so nothing more to do
1277 continue;
1278 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1279 *merge_cp_p, scratch_i)) {
1280 // The mismatch in compare_entry_to() above is because of a
1281 // resolved versus unresolved class entry at the same index
1282 // with the same string value. Since Pass 0 reverted any
1283 // class entries to unresolved class entries in *merge_cp_p,
1284 // we go with the unresolved class entry.
1285 continue;
1286 }
1287
1288 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1289 CHECK_0);
1290 if (found_i != 0) {
1291 guarantee(found_i != scratch_i,
1292 "compare_entry_to() and find_matching_entry() do not agree");
1293
1294 // Found a matching entry somewhere else in *merge_cp_p so
1295 // just need a mapping entry.
1296 map_index(scratch_cp, scratch_i, found_i);
1297 continue;
1298 }
1299
1300 // The find_matching_entry() call above could fail to find a match
1301 // due to a resolved versus unresolved class or string entry situation
1302 // like we solved above with the is_unresolved_*_mismatch() calls.
1303 // However, we would have to call is_unresolved_*_mismatch() over
1304 // all of *merge_cp_p (potentially) and that doesn't seem to be
1305 // worth the time.
1306
1307 // No match found so we have to append this entry and any unique
1308 // referenced entries to *merge_cp_p.
1309 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1310 CHECK_0);
1311 }
1312 }
1313
1314 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1315 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1316 *merge_cp_length_p, scratch_i, _index_map_count));
1317
1318 if (scratch_i < scratch_cp->length()) {
1319 // Pass 1b:
1320 // old_cp is smaller than scratch_cp so there are entries in
1321 // scratch_cp that we have not yet processed. We take care of
1322 // those now.
1323 int increment = 1;
1324 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1325 switch (scratch_cp->tag_at(scratch_i).value()) {
1326 case JVM_CONSTANT_Double:
1327 case JVM_CONSTANT_Long:
1328 // double and long take two constant pool entries
1329 increment = 2;
1330 break;
1331
1332 default:
1333 increment = 1;
1334 break;
1335 }
1336
1337 int found_i =
1338 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1339 if (found_i != 0) {
1340 // Found a matching entry somewhere else in *merge_cp_p so
1341 // just need a mapping entry.
1342 map_index(scratch_cp, scratch_i, found_i);
1343 continue;
1344 }
1345
1346 // No match found so we have to append this entry and any unique
1347 // referenced entries to *merge_cp_p.
1348 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1349 CHECK_0);
1350 }
1351
1352 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1353 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1354 *merge_cp_length_p, scratch_i, _index_map_count));
1355 }
1356 finalize_operands_merge(*merge_cp_p, THREAD);
1357
1358 return true;
1359 } // end merge_constant_pools()
1360
1361
1362 // Scoped object to clean up the constant pool(s) created for merging
1363 class MergeCPCleaner {
1364 ClassLoaderData* _loader_data;
1365 ConstantPool* _cp;
1366 ConstantPool* _scratch_cp;
1367 public:
1368 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1369 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1370 ~MergeCPCleaner() {
1371 _loader_data->add_to_deallocate_list(_cp);
1372 if (_scratch_cp != NULL) {
1373 _loader_data->add_to_deallocate_list(_scratch_cp);
1374 }
1375 }
1376 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1377 };
1378
1379 // Merge constant pools between the_class and scratch_class and
1380 // potentially rewrite bytecodes in scratch_class to use the merged
1381 // constant pool.
1382 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1383 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1384 TRAPS) {
1385 // worst case merged constant pool length is old and new combined
1386 int merge_cp_length = the_class->constants()->length()
1387 + scratch_class->constants()->length();
1388
1389 // Constant pools are not easily reused so we allocate a new one
1390 // each time.
1391 // merge_cp is created unsafe for concurrent GC processing. It
1392 // should be marked safe before discarding it. Even though
1393 // garbage, if it crosses a card boundary, it may be scanned
1394 // in order to find the start of the first complete object on the card.
1395 ClassLoaderData* loader_data = the_class->class_loader_data();
1396 ConstantPool* merge_cp_oop =
1397 ConstantPool::allocate(loader_data,
1398 merge_cp_length,
1399 THREAD);
1400 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1401
1402 HandleMark hm(THREAD); // make sure handles are cleared before
1403 // MergeCPCleaner clears out merge_cp_oop
1404 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1405
1406 // Get constants() from the old class because it could have been rewritten
1407 // while we were at a safepoint allocating a new constant pool.
1408 constantPoolHandle old_cp(THREAD, the_class->constants());
1409 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1410
1411 // If the length changed, the class was redefined out from under us. Return
1412 // an error.
1413 if (merge_cp_length != the_class->constants()->length()
1414 + scratch_class->constants()->length()) {
1415 return JVMTI_ERROR_INTERNAL;
1416 }
1417
1418 // Update the version number of the constant pool
1419 merge_cp->increment_and_save_version(old_cp->version());
1420
1421 ResourceMark rm(THREAD);
1422 _index_map_count = 0;
1423 _index_map_p = new intArray(scratch_cp->length(), -1);
1424
1425 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1426 _operands_index_map_count = 0;
1427 _operands_index_map_p = new intArray(
1428 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1429
1430 // reference to the cp holder is needed for copy_operands()
1431 merge_cp->set_pool_holder(scratch_class());
1432 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1433 &merge_cp_length, THREAD);
1434 merge_cp->set_pool_holder(NULL);
1435
1436 if (!result) {
1437 // The merge can fail due to memory allocation failure or due
1438 // to robustness checks.
1439 return JVMTI_ERROR_INTERNAL;
1440 }
1441
1442 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1443 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1444
1445 if (_index_map_count == 0) {
1446 // there is nothing to map between the new and merged constant pools
1447
1448 if (old_cp->length() == scratch_cp->length()) {
1449 // The old and new constant pools are the same length and the
1450 // index map is empty. This means that the three constant pools
1451 // are equivalent (but not the same). Unfortunately, the new
1452 // constant pool has not gone through link resolution nor have
1453 // the new class bytecodes gone through constant pool cache
1454 // rewriting so we can't use the old constant pool with the new
1455 // class.
1456
1457 // toss the merged constant pool at return
1458 } else if (old_cp->length() < scratch_cp->length()) {
1459 // The old constant pool has fewer entries than the new constant
1460 // pool and the index map is empty. This means the new constant
1461 // pool is a superset of the old constant pool. However, the old
1462 // class bytecodes have already gone through constant pool cache
1463 // rewriting so we can't use the new constant pool with the old
1464 // class.
1465
1466 // toss the merged constant pool at return
1467 } else {
1468 // The old constant pool has more entries than the new constant
1469 // pool and the index map is empty. This means that both the old
1470 // and merged constant pools are supersets of the new constant
1471 // pool.
1472
1473 // Replace the new constant pool with a shrunken copy of the
1474 // merged constant pool
1475 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1476 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1477 // It can't be cleaned up while there are handles to it.
1478 cp_cleaner.add_scratch_cp(scratch_cp());
1479 }
1480 } else {
1481 if (RC_TRACE_ENABLED(0x00040000)) {
1482 // don't want to loop unless we are tracing
1483 int count = 0;
1484 for (int i = 1; i < _index_map_p->length(); i++) {
1485 int value = _index_map_p->at(i);
1486
1487 if (value != -1) {
1488 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1489 ("index_map[%d]: old=%d new=%d", count, i, value));
1490 count++;
1491 }
1492 }
1493 }
1494
1495 // We have entries mapped between the new and merged constant pools
1496 // so we have to rewrite some constant pool references.
1497 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1498 return JVMTI_ERROR_INTERNAL;
1499 }
1500
1501 // Replace the new constant pool with a shrunken copy of the
1502 // merged constant pool so now the rewritten bytecodes have
1503 // valid references; the previous new constant pool will get
1504 // GCed.
1505 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, THREAD);
1506 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1507 // It can't be cleaned up while there are handles to it.
1508 cp_cleaner.add_scratch_cp(scratch_cp());
1509 }
1510
1511 return JVMTI_ERROR_NONE;
1512 } // end merge_cp_and_rewrite()
1513
1514
1515 // Rewrite constant pool references in klass scratch_class.
1516 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1517 TRAPS) {
1518
1519 // rewrite constant pool references in the methods:
1520 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1521 // propagate failure back to caller
1522 return false;
1523 }
1524
1525 // rewrite constant pool references in the class_annotations:
1526 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1527 // propagate failure back to caller
1528 return false;
1529 }
1530
1531 // rewrite constant pool references in the fields_annotations:
1532 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1533 // propagate failure back to caller
1534 return false;
1535 }
1536
1537 // rewrite constant pool references in the methods_annotations:
1538 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1539 // propagate failure back to caller
1540 return false;
1541 }
1542
1543 // rewrite constant pool references in the methods_parameter_annotations:
1544 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1545 THREAD)) {
1546 // propagate failure back to caller
1547 return false;
1548 }
1549
1550 // rewrite constant pool references in the methods_default_annotations:
1551 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1552 THREAD)) {
1553 // propagate failure back to caller
1554 return false;
1555 }
1556
1557 // rewrite source file name index:
1558 u2 source_file_name_idx = scratch_class->source_file_name_index();
1559 if (source_file_name_idx != 0) {
1560 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1561 if (new_source_file_name_idx != 0) {
1562 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1563 }
1564 }
1565
1566 // rewrite class generic signature index:
1567 u2 generic_signature_index = scratch_class->generic_signature_index();
1568 if (generic_signature_index != 0) {
1569 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1570 if (new_generic_signature_index != 0) {
1571 scratch_class->set_generic_signature_index(new_generic_signature_index);
1572 }
1573 }
1574
1575 return true;
1576 } // end rewrite_cp_refs()
1577
1578 // Rewrite constant pool references in the methods.
1579 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1580 instanceKlassHandle scratch_class, TRAPS) {
1581
1582 Array<Method*>* methods = scratch_class->methods();
1583
1584 if (methods == NULL || methods->length() == 0) {
1585 // no methods so nothing to do
1586 return true;
1587 }
1588
1589 // rewrite constant pool references in the methods:
1590 for (int i = methods->length() - 1; i >= 0; i--) {
1591 methodHandle method(THREAD, methods->at(i));
1592 methodHandle new_method;
1593 rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
1594 if (!new_method.is_null()) {
1595 // the method has been replaced so save the new method version
1596 methods->at_put(i, new_method());
1597 }
1598 }
1599
1600 return true;
1601 }
1602
1603
1604 // Rewrite constant pool references in the specific method. This code
1605 // was adapted from Rewriter::rewrite_method().
1606 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1607 methodHandle *new_method_p, TRAPS) {
1608
1609 *new_method_p = methodHandle(); // default is no new method
1610
1611 // We cache a pointer to the bytecodes here in code_base. If GC
1612 // moves the Method*, then the bytecodes will also move which
1613 // will likely cause a crash. We create a No_Safepoint_Verifier
1614 // object to detect whether we pass a possible safepoint in this
1615 // code block.
1616 No_Safepoint_Verifier nsv;
1617
1618 // Bytecodes and their length
1619 address code_base = method->code_base();
1620 int code_length = method->code_size();
1621
1622 int bc_length;
1623 for (int bci = 0; bci < code_length; bci += bc_length) {
1624 address bcp = code_base + bci;
1625 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1626
1627 bc_length = Bytecodes::length_for(c);
1628 if (bc_length == 0) {
1629 // More complicated bytecodes report a length of zero so
1630 // we have to try again a slightly different way.
1631 bc_length = Bytecodes::length_at(method(), bcp);
1632 }
1633
1634 assert(bc_length != 0, "impossible bytecode length");
1635
1636 switch (c) {
1637 case Bytecodes::_ldc:
1638 {
1639 int cp_index = *(bcp + 1);
1640 int new_index = find_new_index(cp_index);
1641
1642 if (StressLdcRewrite && new_index == 0) {
1643 // If we are stressing ldc -> ldc_w rewriting, then we
1644 // always need a new_index value.
1645 new_index = cp_index;
1646 }
1647 if (new_index != 0) {
1648 // the original index is mapped so we have more work to do
1649 if (!StressLdcRewrite && new_index <= max_jubyte) {
1650 // The new value can still use ldc instead of ldc_w
1651 // unless we are trying to stress ldc -> ldc_w rewriting
1652 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1653 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1654 bcp, cp_index, new_index));
1655 *(bcp + 1) = new_index;
1656 } else {
1657 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1658 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1659 Bytecodes::name(c), bcp, cp_index, new_index));
1660 // the new value needs ldc_w instead of ldc
1661 u_char inst_buffer[4]; // max instruction size is 4 bytes
1662 bcp = (address)inst_buffer;
1663 // construct new instruction sequence
1664 *bcp = Bytecodes::_ldc_w;
1665 bcp++;
1666 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1667 // See comment below for difference between put_Java_u2()
1668 // and put_native_u2().
1669 Bytes::put_Java_u2(bcp, new_index);
1670
1671 Relocator rc(method, NULL /* no RelocatorListener needed */);
1672 methodHandle m;
1673 {
1674 Pause_No_Safepoint_Verifier pnsv(&nsv);
1675
1676 // ldc is 2 bytes and ldc_w is 3 bytes
1677 m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
1678 if (m.is_null() || HAS_PENDING_EXCEPTION) {
1679 guarantee(false, "insert_space_at() failed");
1680 }
1681 }
1682
1683 // return the new method so that the caller can update
1684 // the containing class
1685 *new_method_p = method = m;
1686 // switch our bytecode processing loop from the old method
1687 // to the new method
1688 code_base = method->code_base();
1689 code_length = method->code_size();
1690 bcp = code_base + bci;
1691 c = (Bytecodes::Code)(*bcp);
1692 bc_length = Bytecodes::length_for(c);
1693 assert(bc_length != 0, "sanity check");
1694 } // end we need ldc_w instead of ldc
1695 } // end if there is a mapped index
1696 } break;
1697
1698 // these bytecodes have a two-byte constant pool index
1699 case Bytecodes::_anewarray : // fall through
1700 case Bytecodes::_checkcast : // fall through
1701 case Bytecodes::_getfield : // fall through
1702 case Bytecodes::_getstatic : // fall through
1703 case Bytecodes::_instanceof : // fall through
1704 case Bytecodes::_invokedynamic : // fall through
1705 case Bytecodes::_invokeinterface: // fall through
1706 case Bytecodes::_invokespecial : // fall through
1707 case Bytecodes::_invokestatic : // fall through
1708 case Bytecodes::_invokevirtual : // fall through
1709 case Bytecodes::_ldc_w : // fall through
1710 case Bytecodes::_ldc2_w : // fall through
1711 case Bytecodes::_multianewarray : // fall through
1712 case Bytecodes::_new : // fall through
1713 case Bytecodes::_putfield : // fall through
1714 case Bytecodes::_putstatic :
1715 {
1716 address p = bcp + 1;
1717 int cp_index = Bytes::get_Java_u2(p);
1718 int new_index = find_new_index(cp_index);
1719 if (new_index != 0) {
1720 // the original index is mapped so update w/ new value
1721 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1722 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1723 bcp, cp_index, new_index));
1724 // Rewriter::rewrite_method() uses put_native_u2() in this
1725 // situation because it is reusing the constant pool index
1726 // location for a native index into the ConstantPoolCache.
1727 // Since we are updating the constant pool index prior to
1728 // verification and ConstantPoolCache initialization, we
1729 // need to keep the new index in Java byte order.
1730 Bytes::put_Java_u2(p, new_index);
1731 }
1732 } break;
1733 }
1734 } // end for each bytecode
1735
1736 // We also need to rewrite the parameter name indexes, if there is
1737 // method parameter data present
1738 if(method->has_method_parameters()) {
1739 const int len = method->method_parameters_length();
1740 MethodParametersElement* elem = method->method_parameters_start();
1741
1742 for (int i = 0; i < len; i++) {
1743 const u2 cp_index = elem[i].name_cp_index;
1744 const u2 new_cp_index = find_new_index(cp_index);
1745 if (new_cp_index != 0) {
1746 elem[i].name_cp_index = new_cp_index;
1747 }
1748 }
1749 }
1750 } // end rewrite_cp_refs_in_method()
1751
1752
1753 // Rewrite constant pool references in the class_annotations field.
1754 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1755 instanceKlassHandle scratch_class, TRAPS) {
1756
1757 AnnotationArray* class_annotations = scratch_class->class_annotations();
1758 if (class_annotations == NULL || class_annotations->length() == 0) {
1759 // no class_annotations so nothing to do
1760 return true;
1761 }
1762
1763 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1764 ("class_annotations length=%d", class_annotations->length()));
1765
1766 int byte_i = 0; // byte index into class_annotations
1767 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1768 THREAD);
1769 }
1770
1771
1772 // Rewrite constant pool references in an annotations typeArray. This
1773 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1774 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1775 //
1776 // annotations_typeArray {
1777 // u2 num_annotations;
1778 // annotation annotations[num_annotations];
1779 // }
1780 //
1781 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1782 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1783
1784 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1785 // not enough room for num_annotations field
1786 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1787 ("length() is too small for num_annotations field"));
1788 return false;
1789 }
1790
1791 u2 num_annotations = Bytes::get_Java_u2((address)
1792 annotations_typeArray->adr_at(byte_i_ref));
1793 byte_i_ref += 2;
1794
1795 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1796 ("num_annotations=%d", num_annotations));
1797
1798 int calc_num_annotations = 0;
1799 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1800 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1801 byte_i_ref, THREAD)) {
1802 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1803 ("bad annotation_struct at %d", calc_num_annotations));
1804 // propagate failure back to caller
1805 return false;
1806 }
1807 }
1808 assert(num_annotations == calc_num_annotations, "sanity check");
1809
1810 return true;
1811 } // end rewrite_cp_refs_in_annotations_typeArray()
1812
1813
1814 // Rewrite constant pool references in the annotation struct portion of
1815 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1816 // the 2nd-edition of the VM spec:
1817 //
1818 // struct annotation {
1819 // u2 type_index;
1820 // u2 num_element_value_pairs;
1821 // {
1822 // u2 element_name_index;
1823 // element_value value;
1824 // } element_value_pairs[num_element_value_pairs];
1825 // }
1826 //
1827 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1828 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1829 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1830 // not enough room for smallest annotation_struct
1831 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1832 ("length() is too small for annotation_struct"));
1833 return false;
1834 }
1835
1836 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1837 byte_i_ref, "mapped old type_index=%d", THREAD);
1838
1839 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1840 annotations_typeArray->adr_at(byte_i_ref));
1841 byte_i_ref += 2;
1842
1843 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1844 ("type_index=%d num_element_value_pairs=%d", type_index,
1845 num_element_value_pairs));
1846
1847 int calc_num_element_value_pairs = 0;
1848 for (; calc_num_element_value_pairs < num_element_value_pairs;
1849 calc_num_element_value_pairs++) {
1850 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1851 // not enough room for another element_name_index, let alone
1852 // the rest of another component
1853 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1854 ("length() is too small for element_name_index"));
1855 return false;
1856 }
1857
1858 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1859 annotations_typeArray, byte_i_ref,
1860 "mapped old element_name_index=%d", THREAD);
1861
1862 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1863 ("element_name_index=%d", element_name_index));
1864
1865 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1866 byte_i_ref, THREAD)) {
1867 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1868 ("bad element_value at %d", calc_num_element_value_pairs));
1869 // propagate failure back to caller
1870 return false;
1871 }
1872 } // end for each component
1873 assert(num_element_value_pairs == calc_num_element_value_pairs,
1874 "sanity check");
1875
1876 return true;
1877 } // end rewrite_cp_refs_in_annotation_struct()
1878
1879
1880 // Rewrite a constant pool reference at the current position in
1881 // annotations_typeArray if needed. Returns the original constant
1882 // pool reference if a rewrite was not needed or the new constant
1883 // pool reference if a rewrite was needed.
1884 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1885 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1886 const char * trace_mesg, TRAPS) {
1887
1888 address cp_index_addr = (address)
1889 annotations_typeArray->adr_at(byte_i_ref);
1890 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1891 u2 new_cp_index = find_new_index(old_cp_index);
1892 if (new_cp_index != 0) {
1893 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1894 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1895 old_cp_index = new_cp_index;
1896 }
1897 byte_i_ref += 2;
1898 return old_cp_index;
1899 }
1900
1901
1902 // Rewrite constant pool references in the element_value portion of an
1903 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1904 // the 2nd-edition of the VM spec:
1905 //
1906 // struct element_value {
1907 // u1 tag;
1908 // union {
1909 // u2 const_value_index;
1910 // {
1911 // u2 type_name_index;
1912 // u2 const_name_index;
1913 // } enum_const_value;
1914 // u2 class_info_index;
1915 // annotation annotation_value;
1916 // struct {
1917 // u2 num_values;
1918 // element_value values[num_values];
1919 // } array_value;
1920 // } value;
1921 // }
1922 //
1923 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1924 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1925
1926 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1927 // not enough room for a tag let alone the rest of an element_value
1928 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1929 ("length() is too small for a tag"));
1930 return false;
1931 }
1932
1933 u1 tag = annotations_typeArray->at(byte_i_ref);
1934 byte_i_ref++;
1935 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1936
1937 switch (tag) {
1938 // These BaseType tag values are from Table 4.2 in VM spec:
1939 case 'B': // byte
1940 case 'C': // char
1941 case 'D': // double
1942 case 'F': // float
1943 case 'I': // int
1944 case 'J': // long
1945 case 'S': // short
1946 case 'Z': // boolean
1947
1948 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1949 // the VM spec:
1950 case 's':
1951 {
1952 // For the above tag values (including the BaseType values),
1953 // value.const_value_index is right union field.
1954
1955 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1956 // not enough room for a const_value_index
1957 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1958 ("length() is too small for a const_value_index"));
1959 return false;
1960 }
1961
1962 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1963 annotations_typeArray, byte_i_ref,
1964 "mapped old const_value_index=%d", THREAD);
1965
1966 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1967 ("const_value_index=%d", const_value_index));
1968 } break;
1969
1970 case 'e':
1971 {
1972 // for the above tag value, value.enum_const_value is right union field
1973
1974 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1975 // not enough room for a enum_const_value
1976 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1977 ("length() is too small for a enum_const_value"));
1978 return false;
1979 }
1980
1981 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1982 annotations_typeArray, byte_i_ref,
1983 "mapped old type_name_index=%d", THREAD);
1984
1985 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1986 annotations_typeArray, byte_i_ref,
1987 "mapped old const_name_index=%d", THREAD);
1988
1989 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1990 ("type_name_index=%d const_name_index=%d", type_name_index,
1991 const_name_index));
1992 } break;
1993
1994 case 'c':
1995 {
1996 // for the above tag value, value.class_info_index is right union field
1997
1998 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1999 // not enough room for a class_info_index
2000 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2001 ("length() is too small for a class_info_index"));
2002 return false;
2003 }
2004
2005 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2006 annotations_typeArray, byte_i_ref,
2007 "mapped old class_info_index=%d", THREAD);
2008
2009 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2010 ("class_info_index=%d", class_info_index));
2011 } break;
2012
2013 case '@':
2014 // For the above tag value, value.attr_value is the right union
2015 // field. This is a nested annotation.
2016 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2017 byte_i_ref, THREAD)) {
2018 // propagate failure back to caller
2019 return false;
2020 }
2021 break;
2022
2023 case '[':
2024 {
2025 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2026 // not enough room for a num_values field
2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2028 ("length() is too small for a num_values field"));
2029 return false;
2030 }
2031
2032 // For the above tag value, value.array_value is the right union
2033 // field. This is an array of nested element_value.
2034 u2 num_values = Bytes::get_Java_u2((address)
2035 annotations_typeArray->adr_at(byte_i_ref));
2036 byte_i_ref += 2;
2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2038
2039 int calc_num_values = 0;
2040 for (; calc_num_values < num_values; calc_num_values++) {
2041 if (!rewrite_cp_refs_in_element_value(
2042 annotations_typeArray, byte_i_ref, THREAD)) {
2043 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2044 ("bad nested element_value at %d", calc_num_values));
2045 // propagate failure back to caller
2046 return false;
2047 }
2048 }
2049 assert(num_values == calc_num_values, "sanity check");
2050 } break;
2051
2052 default:
2053 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2054 return false;
2055 } // end decode tag field
2056
2057 return true;
2058 } // end rewrite_cp_refs_in_element_value()
2059
2060
2061 // Rewrite constant pool references in a fields_annotations field.
2062 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2063 instanceKlassHandle scratch_class, TRAPS) {
2064
2065 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2066
2067 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2068 // no fields_annotations so nothing to do
2069 return true;
2070 }
2071
2072 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2073 ("fields_annotations length=%d", fields_annotations->length()));
2074
2075 for (int i = 0; i < fields_annotations->length(); i++) {
2076 AnnotationArray* field_annotations = fields_annotations->at(i);
2077 if (field_annotations == NULL || field_annotations->length() == 0) {
2078 // this field does not have any annotations so skip it
2079 continue;
2080 }
2081
2082 int byte_i = 0; // byte index into field_annotations
2083 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2084 THREAD)) {
2085 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2086 ("bad field_annotations at %d", i));
2087 // propagate failure back to caller
2088 return false;
2089 }
2090 }
2091
2092 return true;
2093 } // end rewrite_cp_refs_in_fields_annotations()
2094
2095
2096 // Rewrite constant pool references in a methods_annotations field.
2097 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2098 instanceKlassHandle scratch_class, TRAPS) {
2099
2100 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2101 Method* m = scratch_class->methods()->at(i);
2102 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2103
2104 if (method_annotations == NULL || method_annotations->length() == 0) {
2105 // this method does not have any annotations so skip it
2106 continue;
2107 }
2108
2109 int byte_i = 0; // byte index into method_annotations
2110 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2111 THREAD)) {
2112 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2113 ("bad method_annotations at %d", i));
2114 // propagate failure back to caller
2115 return false;
2116 }
2117 }
2118
2119 return true;
2120 } // end rewrite_cp_refs_in_methods_annotations()
2121
2122
2123 // Rewrite constant pool references in a methods_parameter_annotations
2124 // field. This "structure" is adapted from the
2125 // RuntimeVisibleParameterAnnotations_attribute described in section
2126 // 4.8.17 of the 2nd-edition of the VM spec:
2127 //
2128 // methods_parameter_annotations_typeArray {
2129 // u1 num_parameters;
2130 // {
2131 // u2 num_annotations;
2132 // annotation annotations[num_annotations];
2133 // } parameter_annotations[num_parameters];
2134 // }
2135 //
2136 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2137 instanceKlassHandle scratch_class, TRAPS) {
2138
2139 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2140 Method* m = scratch_class->methods()->at(i);
2141 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2142 if (method_parameter_annotations == NULL
2143 || method_parameter_annotations->length() == 0) {
2144 // this method does not have any parameter annotations so skip it
2145 continue;
2146 }
2147
2148 if (method_parameter_annotations->length() < 1) {
2149 // not enough room for a num_parameters field
2150 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2151 ("length() is too small for a num_parameters field at %d", i));
2152 return false;
2153 }
2154
2155 int byte_i = 0; // byte index into method_parameter_annotations
2156
2157 u1 num_parameters = method_parameter_annotations->at(byte_i);
2158 byte_i++;
2159
2160 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2161 ("num_parameters=%d", num_parameters));
2162
2163 int calc_num_parameters = 0;
2164 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2165 if (!rewrite_cp_refs_in_annotations_typeArray(
2166 method_parameter_annotations, byte_i, THREAD)) {
2167 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2168 ("bad method_parameter_annotations at %d", calc_num_parameters));
2169 // propagate failure back to caller
2170 return false;
2171 }
2172 }
2173 assert(num_parameters == calc_num_parameters, "sanity check");
2174 }
2175
2176 return true;
2177 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2178
2179
2180 // Rewrite constant pool references in a methods_default_annotations
2181 // field. This "structure" is adapted from the AnnotationDefault_attribute
2182 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2183 //
2184 // methods_default_annotations_typeArray {
2185 // element_value default_value;
2186 // }
2187 //
2188 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2189 instanceKlassHandle scratch_class, TRAPS) {
2190
2191 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2192 Method* m = scratch_class->methods()->at(i);
2193 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2194 if (method_default_annotations == NULL
2195 || method_default_annotations->length() == 0) {
2196 // this method does not have any default annotations so skip it
2197 continue;
2198 }
2199
2200 int byte_i = 0; // byte index into method_default_annotations
2201
2202 if (!rewrite_cp_refs_in_element_value(
2203 method_default_annotations, byte_i, THREAD)) {
2204 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2205 ("bad default element_value at %d", i));
2206 // propagate failure back to caller
2207 return false;
2208 }
2209 }
2210
2211 return true;
2212 } // end rewrite_cp_refs_in_methods_default_annotations()
2213
2214
2215 // Rewrite constant pool references in the method's stackmap table.
2216 // These "structures" are adapted from the StackMapTable_attribute that
2217 // is described in section 4.8.4 of the 6.0 version of the VM spec
2218 // (dated 2005.10.26):
2219 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2220 //
2221 // stack_map {
2222 // u2 number_of_entries;
2223 // stack_map_frame entries[number_of_entries];
2224 // }
2225 //
2226 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2227 methodHandle method, TRAPS) {
2228
2229 if (!method->has_stackmap_table()) {
2230 return;
2231 }
2232
2233 AnnotationArray* stackmap_data = method->stackmap_data();
2234 address stackmap_p = (address)stackmap_data->adr_at(0);
2235 address stackmap_end = stackmap_p + stackmap_data->length();
2236
2237 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2238 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2239 stackmap_p += 2;
2240
2241 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2242 ("number_of_entries=%u", number_of_entries));
2243
2244 // walk through each stack_map_frame
2245 u2 calc_number_of_entries = 0;
2246 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2247 // The stack_map_frame structure is a u1 frame_type followed by
2248 // 0 or more bytes of data:
2249 //
2250 // union stack_map_frame {
2251 // same_frame;
2252 // same_locals_1_stack_item_frame;
2253 // same_locals_1_stack_item_frame_extended;
2254 // chop_frame;
2255 // same_frame_extended;
2256 // append_frame;
2257 // full_frame;
2258 // }
2259
2260 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2261 // The Linux compiler does not like frame_type to be u1 or u2. It
2262 // issues the following warning for the first if-statement below:
2263 //
2264 // "warning: comparison is always true due to limited range of data type"
2265 //
2266 u4 frame_type = *stackmap_p;
2267 stackmap_p++;
2268
2269 // same_frame {
2270 // u1 frame_type = SAME; /* 0-63 */
2271 // }
2272 if (frame_type >= 0 && frame_type <= 63) {
2273 // nothing more to do for same_frame
2274 }
2275
2276 // same_locals_1_stack_item_frame {
2277 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2278 // verification_type_info stack[1];
2279 // }
2280 else if (frame_type >= 64 && frame_type <= 127) {
2281 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2282 calc_number_of_entries, frame_type, THREAD);
2283 }
2284
2285 // reserved for future use
2286 else if (frame_type >= 128 && frame_type <= 246) {
2287 // nothing more to do for reserved frame_types
2288 }
2289
2290 // same_locals_1_stack_item_frame_extended {
2291 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2292 // u2 offset_delta;
2293 // verification_type_info stack[1];
2294 // }
2295 else if (frame_type == 247) {
2296 stackmap_p += 2;
2297 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2298 calc_number_of_entries, frame_type, THREAD);
2299 }
2300
2301 // chop_frame {
2302 // u1 frame_type = CHOP; /* 248-250 */
2303 // u2 offset_delta;
2304 // }
2305 else if (frame_type >= 248 && frame_type <= 250) {
2306 stackmap_p += 2;
2307 }
2308
2309 // same_frame_extended {
2310 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2311 // u2 offset_delta;
2312 // }
2313 else if (frame_type == 251) {
2314 stackmap_p += 2;
2315 }
2316
2317 // append_frame {
2318 // u1 frame_type = APPEND; /* 252-254 */
2319 // u2 offset_delta;
2320 // verification_type_info locals[frame_type - 251];
2321 // }
2322 else if (frame_type >= 252 && frame_type <= 254) {
2323 assert(stackmap_p + 2 <= stackmap_end,
2324 "no room for offset_delta");
2325 stackmap_p += 2;
2326 u1 len = frame_type - 251;
2327 for (u1 i = 0; i < len; i++) {
2328 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2329 calc_number_of_entries, frame_type, THREAD);
2330 }
2331 }
2332
2333 // full_frame {
2334 // u1 frame_type = FULL_FRAME; /* 255 */
2335 // u2 offset_delta;
2336 // u2 number_of_locals;
2337 // verification_type_info locals[number_of_locals];
2338 // u2 number_of_stack_items;
2339 // verification_type_info stack[number_of_stack_items];
2340 // }
2341 else if (frame_type == 255) {
2342 assert(stackmap_p + 2 + 2 <= stackmap_end,
2343 "no room for smallest full_frame");
2344 stackmap_p += 2;
2345
2346 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2347 stackmap_p += 2;
2348
2349 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2350 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2351 calc_number_of_entries, frame_type, THREAD);
2352 }
2353
2354 // Use the largest size for the number_of_stack_items, but only get
2355 // the right number of bytes.
2356 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2357 stackmap_p += 2;
2358
2359 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2360 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2361 calc_number_of_entries, frame_type, THREAD);
2362 }
2363 }
2364 } // end while there is a stack_map_frame
2365 assert(number_of_entries == calc_number_of_entries, "sanity check");
2366 } // end rewrite_cp_refs_in_stack_map_table()
2367
2368
2369 // Rewrite constant pool references in the verification type info
2370 // portion of the method's stackmap table. These "structures" are
2371 // adapted from the StackMapTable_attribute that is described in
2372 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2373 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2374 //
2375 // The verification_type_info structure is a u1 tag followed by 0 or
2376 // more bytes of data:
2377 //
2378 // union verification_type_info {
2379 // Top_variable_info;
2380 // Integer_variable_info;
2381 // Float_variable_info;
2382 // Long_variable_info;
2383 // Double_variable_info;
2384 // Null_variable_info;
2385 // UninitializedThis_variable_info;
2386 // Object_variable_info;
2387 // Uninitialized_variable_info;
2388 // }
2389 //
2390 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2391 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2392 u1 frame_type, TRAPS) {
2393
2394 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2395 u1 tag = *stackmap_p_ref;
2396 stackmap_p_ref++;
2397
2398 switch (tag) {
2399 // Top_variable_info {
2400 // u1 tag = ITEM_Top; /* 0 */
2401 // }
2402 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2403 case 0: // fall through
2404
2405 // Integer_variable_info {
2406 // u1 tag = ITEM_Integer; /* 1 */
2407 // }
2408 case ITEM_Integer: // fall through
2409
2410 // Float_variable_info {
2411 // u1 tag = ITEM_Float; /* 2 */
2412 // }
2413 case ITEM_Float: // fall through
2414
2415 // Double_variable_info {
2416 // u1 tag = ITEM_Double; /* 3 */
2417 // }
2418 case ITEM_Double: // fall through
2419
2420 // Long_variable_info {
2421 // u1 tag = ITEM_Long; /* 4 */
2422 // }
2423 case ITEM_Long: // fall through
2424
2425 // Null_variable_info {
2426 // u1 tag = ITEM_Null; /* 5 */
2427 // }
2428 case ITEM_Null: // fall through
2429
2430 // UninitializedThis_variable_info {
2431 // u1 tag = ITEM_UninitializedThis; /* 6 */
2432 // }
2433 case ITEM_UninitializedThis:
2434 // nothing more to do for the above tag types
2435 break;
2436
2437 // Object_variable_info {
2438 // u1 tag = ITEM_Object; /* 7 */
2439 // u2 cpool_index;
2440 // }
2441 case ITEM_Object:
2442 {
2443 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2444 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2445 u2 new_cp_index = find_new_index(cpool_index);
2446 if (new_cp_index != 0) {
2447 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2448 ("mapped old cpool_index=%d", cpool_index));
2449 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2450 cpool_index = new_cp_index;
2451 }
2452 stackmap_p_ref += 2;
2453
2454 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2455 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2456 frame_type, cpool_index));
2457 } break;
2458
2459 // Uninitialized_variable_info {
2460 // u1 tag = ITEM_Uninitialized; /* 8 */
2461 // u2 offset;
2462 // }
2463 case ITEM_Uninitialized:
2464 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2465 stackmap_p_ref += 2;
2466 break;
2467
2468 default:
2469 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2470 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2471 ShouldNotReachHere();
2472 break;
2473 } // end switch (tag)
2474 } // end rewrite_cp_refs_in_verification_type_info()
2475
2476
2477 // Change the constant pool associated with klass scratch_class to
2478 // scratch_cp. If shrink is true, then scratch_cp_length elements
2479 // are copied from scratch_cp to a smaller constant pool and the
2480 // smaller constant pool is associated with scratch_class.
2481 void VM_RedefineClasses::set_new_constant_pool(
2482 ClassLoaderData* loader_data,
2483 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2484 int scratch_cp_length, TRAPS) {
2485 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2486
2487 // scratch_cp is a merged constant pool and has enough space for a
2488 // worst case merge situation. We want to associate the minimum
2489 // sized constant pool with the klass to save space.
2490 constantPoolHandle smaller_cp(THREAD,
2491 ConstantPool::allocate(loader_data, scratch_cp_length, THREAD));
2492
2493 // preserve version() value in the smaller copy
2494 int version = scratch_cp->version();
2495 assert(version != 0, "sanity check");
2496 smaller_cp->set_version(version);
2497
2498 // attach klass to new constant pool
2499 // reference to the cp holder is needed for copy_operands()
2500 smaller_cp->set_pool_holder(scratch_class());
2501
2502 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2503 scratch_cp = smaller_cp;
2504
2505 // attach new constant pool to klass
2506 scratch_class->set_constants(scratch_cp());
2507
2508 int i; // for portability
2509
2510 // update each field in klass to use new constant pool indices as needed
2511 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2512 jshort cur_index = fs.name_index();
2513 jshort new_index = find_new_index(cur_index);
2514 if (new_index != 0) {
2515 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2516 ("field-name_index change: %d to %d", cur_index, new_index));
2517 fs.set_name_index(new_index);
2518 }
2519 cur_index = fs.signature_index();
2520 new_index = find_new_index(cur_index);
2521 if (new_index != 0) {
2522 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2523 ("field-signature_index change: %d to %d", cur_index, new_index));
2524 fs.set_signature_index(new_index);
2525 }
2526 cur_index = fs.initval_index();
2527 new_index = find_new_index(cur_index);
2528 if (new_index != 0) {
2529 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2530 ("field-initval_index change: %d to %d", cur_index, new_index));
2531 fs.set_initval_index(new_index);
2532 }
2533 cur_index = fs.generic_signature_index();
2534 new_index = find_new_index(cur_index);
2535 if (new_index != 0) {
2536 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2537 ("field-generic_signature change: %d to %d", cur_index, new_index));
2538 fs.set_generic_signature_index(new_index);
2539 }
2540 } // end for each field
2541
2542 // Update constant pool indices in the inner classes info to use
2543 // new constant indices as needed. The inner classes info is a
2544 // quadruple:
2545 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2546 InnerClassesIterator iter(scratch_class);
2547 for (; !iter.done(); iter.next()) {
2548 int cur_index = iter.inner_class_info_index();
2549 if (cur_index == 0) {
2550 continue; // JVM spec. allows null inner class refs so skip it
2551 }
2552 int new_index = find_new_index(cur_index);
2553 if (new_index != 0) {
2554 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2555 ("inner_class_info change: %d to %d", cur_index, new_index));
2556 iter.set_inner_class_info_index(new_index);
2557 }
2558 cur_index = iter.outer_class_info_index();
2559 new_index = find_new_index(cur_index);
2560 if (new_index != 0) {
2561 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2562 ("outer_class_info change: %d to %d", cur_index, new_index));
2563 iter.set_outer_class_info_index(new_index);
2564 }
2565 cur_index = iter.inner_name_index();
2566 new_index = find_new_index(cur_index);
2567 if (new_index != 0) {
2568 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2569 ("inner_name change: %d to %d", cur_index, new_index));
2570 iter.set_inner_name_index(new_index);
2571 }
2572 } // end for each inner class
2573
2574 // Attach each method in klass to the new constant pool and update
2575 // to use new constant pool indices as needed:
2576 Array<Method*>* methods = scratch_class->methods();
2577 for (i = methods->length() - 1; i >= 0; i--) {
2578 methodHandle method(THREAD, methods->at(i));
2579 method->set_constants(scratch_cp());
2580
2581 int new_index = find_new_index(method->name_index());
2582 if (new_index != 0) {
2583 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2584 ("method-name_index change: %d to %d", method->name_index(),
2585 new_index));
2586 method->set_name_index(new_index);
2587 }
2588 new_index = find_new_index(method->signature_index());
2589 if (new_index != 0) {
2590 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2591 ("method-signature_index change: %d to %d",
2592 method->signature_index(), new_index));
2593 method->set_signature_index(new_index);
2594 }
2595 new_index = find_new_index(method->generic_signature_index());
2596 if (new_index != 0) {
2597 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2598 ("method-generic_signature_index change: %d to %d",
2599 method->generic_signature_index(), new_index));
2600 method->set_generic_signature_index(new_index);
2601 }
2602
2603 // Update constant pool indices in the method's checked exception
2604 // table to use new constant indices as needed.
2605 int cext_length = method->checked_exceptions_length();
2606 if (cext_length > 0) {
2607 CheckedExceptionElement * cext_table =
2608 method->checked_exceptions_start();
2609 for (int j = 0; j < cext_length; j++) {
2610 int cur_index = cext_table[j].class_cp_index;
2611 int new_index = find_new_index(cur_index);
2612 if (new_index != 0) {
2613 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2614 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2615 cext_table[j].class_cp_index = (u2)new_index;
2616 }
2617 } // end for each checked exception table entry
2618 } // end if there are checked exception table entries
2619
2620 // Update each catch type index in the method's exception table
2621 // to use new constant pool indices as needed. The exception table
2622 // holds quadruple entries of the form:
2623 // (beg_bci, end_bci, handler_bci, klass_index)
2624
2625 ExceptionTable ex_table(method());
2626 int ext_length = ex_table.length();
2627
2628 for (int j = 0; j < ext_length; j ++) {
2629 int cur_index = ex_table.catch_type_index(j);
2630 int new_index = find_new_index(cur_index);
2631 if (new_index != 0) {
2632 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2633 ("ext-klass_index change: %d to %d", cur_index, new_index));
2634 ex_table.set_catch_type_index(j, new_index);
2635 }
2636 } // end for each exception table entry
2637
2638 // Update constant pool indices in the method's local variable
2639 // table to use new constant indices as needed. The local variable
2640 // table hold sextuple entries of the form:
2641 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2642 int lvt_length = method->localvariable_table_length();
2643 if (lvt_length > 0) {
2644 LocalVariableTableElement * lv_table =
2645 method->localvariable_table_start();
2646 for (int j = 0; j < lvt_length; j++) {
2647 int cur_index = lv_table[j].name_cp_index;
2648 int new_index = find_new_index(cur_index);
2649 if (new_index != 0) {
2650 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2651 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2652 lv_table[j].name_cp_index = (u2)new_index;
2653 }
2654 cur_index = lv_table[j].descriptor_cp_index;
2655 new_index = find_new_index(cur_index);
2656 if (new_index != 0) {
2657 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2658 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2659 new_index));
2660 lv_table[j].descriptor_cp_index = (u2)new_index;
2661 }
2662 cur_index = lv_table[j].signature_cp_index;
2663 new_index = find_new_index(cur_index);
2664 if (new_index != 0) {
2665 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2666 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2667 lv_table[j].signature_cp_index = (u2)new_index;
2668 }
2669 } // end for each local variable table entry
2670 } // end if there are local variable table entries
2671
2672 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2673 } // end for each method
2674 } // end set_new_constant_pool()
2675
2676
2677 // Unevolving classes may point to methods of the_class directly
2678 // from their constant pool caches, itables, and/or vtables. We
2679 // use the ClassLoaderDataGraph::classes_do() facility and this helper
2680 // to fix up these pointers.
2681
2682 // Adjust cpools and vtables closure
2683 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
2684
2685 // This is a very busy routine. We don't want too much tracing
2686 // printed out.
2687 bool trace_name_printed = false;
2688
2689 // Very noisy: only enable this call if you are trying to determine
2690 // that a specific class gets found by this routine.
2691 // RC_TRACE macro has an embedded ResourceMark
2692 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2693 // ("adjust check: name=%s", k->external_name()));
2694 // trace_name_printed = true;
2695
2696 // If the class being redefined is java.lang.Object, we need to fix all
2697 // array class vtables also
2698 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
2699 k->vtable()->adjust_method_entries(_matching_old_methods,
2700 _matching_new_methods,
2701 _matching_methods_length,
2702 &trace_name_printed);
2703 } else if (k->oop_is_instance()) {
2704 HandleMark hm(_thread);
2705 InstanceKlass *ik = InstanceKlass::cast(k);
2706
2707 // HotSpot specific optimization! HotSpot does not currently
2708 // support delegation from the bootstrap class loader to a
2709 // user-defined class loader. This means that if the bootstrap
2710 // class loader is the initiating class loader, then it will also
2711 // be the defining class loader. This also means that classes
2712 // loaded by the bootstrap class loader cannot refer to classes
2713 // loaded by a user-defined class loader. Note: a user-defined
2714 // class loader can delegate to the bootstrap class loader.
2715 //
2716 // If the current class being redefined has a user-defined class
2717 // loader as its defining class loader, then we can skip all
2718 // classes loaded by the bootstrap class loader.
2719 bool is_user_defined =
2720 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2721 if (is_user_defined && ik->class_loader() == NULL) {
2722 return;
2723 }
2724
2725 // Fix the vtable embedded in the_class and subclasses of the_class,
2726 // if one exists. We discard scratch_class and we don't keep an
2727 // InstanceKlass around to hold obsolete methods so we don't have
2728 // any other InstanceKlass embedded vtables to update. The vtable
2729 // holds the Method*s for virtual (but not final) methods.
2730 if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
2731 // ik->vtable() creates a wrapper object; rm cleans it up
2732 ResourceMark rm(_thread);
2733 ik->vtable()->adjust_method_entries(_matching_old_methods,
2734 _matching_new_methods,
2735 _matching_methods_length,
2736 &trace_name_printed);
2737 }
2738
2739 // If the current class has an itable and we are either redefining an
2740 // interface or if the current class is a subclass of the_class, then
2741 // we potentially have to fix the itable. If we are redefining an
2742 // interface, then we have to call adjust_method_entries() for
2743 // every InstanceKlass that has an itable since there isn't a
2744 // subclass relationship between an interface and an InstanceKlass.
2745 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2746 || ik->is_subclass_of(_the_class_oop))) {
2747 // ik->itable() creates a wrapper object; rm cleans it up
2748 ResourceMark rm(_thread);
2749 ik->itable()->adjust_method_entries(_matching_old_methods,
2750 _matching_new_methods,
2751 _matching_methods_length,
2752 &trace_name_printed);
2753 }
2754
2755 // The constant pools in other classes (other_cp) can refer to
2756 // methods in the_class. We have to update method information in
2757 // other_cp's cache. If other_cp has a previous version, then we
2758 // have to repeat the process for each previous version. The
2759 // constant pool cache holds the Method*s for non-virtual
2760 // methods and for virtual, final methods.
2761 //
2762 // Special case: if the current class is the_class, then new_cp
2763 // has already been attached to the_class and old_cp has already
2764 // been added as a previous version. The new_cp doesn't have any
2765 // cached references to old methods so it doesn't need to be
2766 // updated. We can simply start with the previous version(s) in
2767 // that case.
2768 constantPoolHandle other_cp;
2769 ConstantPoolCache* cp_cache;
2770
2771 if (ik != _the_class_oop) {
2772 // this klass' constant pool cache may need adjustment
2773 other_cp = constantPoolHandle(ik->constants());
2774 cp_cache = other_cp->cache();
2775 if (cp_cache != NULL) {
2776 cp_cache->adjust_method_entries(_matching_old_methods,
2777 _matching_new_methods,
2778 _matching_methods_length,
2779 &trace_name_printed);
2780 }
2781 }
2782 {
2783 ResourceMark rm(_thread);
2784 // PreviousVersionInfo objects returned via PreviousVersionWalker
2785 // contain a GrowableArray of handles. We have to clean up the
2786 // GrowableArray _after_ the PreviousVersionWalker destructor
2787 // has destroyed the handles.
2788 {
2789 // the previous versions' constant pool caches may need adjustment
2790 PreviousVersionWalker pvw(ik);
2791 for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
2792 pv_info != NULL; pv_info = pvw.next_previous_version()) {
2793 other_cp = pv_info->prev_constant_pool_handle();
2794 cp_cache = other_cp->cache();
2795 if (cp_cache != NULL) {
2796 cp_cache->adjust_method_entries(_matching_old_methods,
2797 _matching_new_methods,
2798 _matching_methods_length,
2799 &trace_name_printed);
2800 }
2801 }
2802 } // pvw is cleaned up
2803 } // rm is cleaned up
2804 }
2805 }
2806
2807 void VM_RedefineClasses::update_jmethod_ids() {
2808 for (int j = 0; j < _matching_methods_length; ++j) {
2809 Method* old_method = _matching_old_methods[j];
2810 jmethodID jmid = old_method->find_jmethod_id_or_null();
2811 if (jmid != NULL) {
2812 // There is a jmethodID, change it to point to the new method
2813 methodHandle new_method_h(_matching_new_methods[j]);
2814 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2815 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2816 "should be replaced");
2817 }
2818 }
2819 }
2820
2821 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2822 BitMap *emcp_methods, int * emcp_method_count_p) {
2823 *emcp_method_count_p = 0;
2824 int obsolete_count = 0;
2825 int old_index = 0;
2826 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2827 Method* old_method = _matching_old_methods[j];
2828 Method* new_method = _matching_new_methods[j];
2829 Method* old_array_method;
2830
2831 // Maintain an old_index into the _old_methods array by skipping
2832 // deleted methods
2833 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2834 ++old_index;
2835 }
2836
2837 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2838 // The EMCP definition from JSR-163 requires the bytecodes to be
2839 // the same with the exception of constant pool indices which may
2840 // differ. However, the constants referred to by those indices
2841 // must be the same.
2842 //
2843 // We use methods_EMCP() for comparison since constant pool
2844 // merging can remove duplicate constant pool entries that were
2845 // present in the old method and removed from the rewritten new
2846 // method. A faster binary comparison function would consider the
2847 // old and new methods to be different when they are actually
2848 // EMCP.
2849 //
2850 // The old and new methods are EMCP and you would think that we
2851 // could get rid of one of them here and now and save some space.
2852 // However, the concept of EMCP only considers the bytecodes and
2853 // the constant pool entries in the comparison. Other things,
2854 // e.g., the line number table (LNT) or the local variable table
2855 // (LVT) don't count in the comparison. So the new (and EMCP)
2856 // method can have a new LNT that we need so we can't just
2857 // overwrite the new method with the old method.
2858 //
2859 // When this routine is called, we have already attached the new
2860 // methods to the_class so the old methods are effectively
2861 // overwritten. However, if an old method is still executing,
2862 // then the old method cannot be collected until sometime after
2863 // the old method call has returned. So the overwriting of old
2864 // methods by new methods will save us space except for those
2865 // (hopefully few) old methods that are still executing.
2866 //
2867 // A method refers to a ConstMethod* and this presents another
2868 // possible avenue to space savings. The ConstMethod* in the
2869 // new method contains possibly new attributes (LNT, LVT, etc).
2870 // At first glance, it seems possible to save space by replacing
2871 // the ConstMethod* in the old method with the ConstMethod*
2872 // from the new method. The old and new methods would share the
2873 // same ConstMethod* and we would save the space occupied by
2874 // the old ConstMethod*. However, the ConstMethod* contains
2875 // a back reference to the containing method. Sharing the
2876 // ConstMethod* between two methods could lead to confusion in
2877 // the code that uses the back reference. This would lead to
2878 // brittle code that could be broken in non-obvious ways now or
2879 // in the future.
2880 //
2881 // Another possibility is to copy the ConstMethod* from the new
2882 // method to the old method and then overwrite the new method with
2883 // the old method. Since the ConstMethod* contains the bytecodes
2884 // for the method embedded in the oop, this option would change
2885 // the bytecodes out from under any threads executing the old
2886 // method and make the thread's bcp invalid. Since EMCP requires
2887 // that the bytecodes be the same modulo constant pool indices, it
2888 // is straight forward to compute the correct new bcp in the new
2889 // ConstMethod* from the old bcp in the old ConstMethod*. The
2890 // time consuming part would be searching all the frames in all
2891 // of the threads to find all of the calls to the old method.
2892 //
2893 // It looks like we will have to live with the limited savings
2894 // that we get from effectively overwriting the old methods
2895 // when the new methods are attached to the_class.
2896
2897 // track which methods are EMCP for add_previous_version() call
2898 emcp_methods->set_bit(old_index);
2899 (*emcp_method_count_p)++;
2900
2901 // An EMCP method is _not_ obsolete. An obsolete method has a
2902 // different jmethodID than the current method. An EMCP method
2903 // has the same jmethodID as the current method. Having the
2904 // same jmethodID for all EMCP versions of a method allows for
2905 // a consistent view of the EMCP methods regardless of which
2906 // EMCP method you happen to have in hand. For example, a
2907 // breakpoint set in one EMCP method will work for all EMCP
2908 // versions of the method including the current one.
2909 } else {
2910 // mark obsolete methods as such
2911 old_method->set_is_obsolete();
2912 obsolete_count++;
2913
2914 // obsolete methods need a unique idnum
2915 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2916 if (num != ConstMethod::UNSET_IDNUM) {
2917 // u2 old_num = old_method->method_idnum();
2918 old_method->set_method_idnum(num);
2919 // TO DO: attach obsolete annotations to obsolete method's new idnum
2920 }
2921 // With tracing we try not to "yack" too much. The position of
2922 // this trace assumes there are fewer obsolete methods than
2923 // EMCP methods.
2924 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2925 old_method->name()->as_C_string(),
2926 old_method->signature()->as_C_string()));
2927 }
2928 old_method->set_is_old();
2929 }
2930 for (int i = 0; i < _deleted_methods_length; ++i) {
2931 Method* old_method = _deleted_methods[i];
2932
2933 assert(old_method->vtable_index() < 0,
2934 "cannot delete methods with vtable entries");;
2935
2936 // Mark all deleted methods as old and obsolete
2937 old_method->set_is_old();
2938 old_method->set_is_obsolete();
2939 ++obsolete_count;
2940 // With tracing we try not to "yack" too much. The position of
2941 // this trace assumes there are fewer obsolete methods than
2942 // EMCP methods.
2943 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2944 old_method->name()->as_C_string(),
2945 old_method->signature()->as_C_string()));
2946 }
2947 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2948 "sanity check");
2949 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2950 obsolete_count));
2951 }
2952
2953 // This internal class transfers the native function registration from old methods
2954 // to new methods. It is designed to handle both the simple case of unchanged
2955 // native methods and the complex cases of native method prefixes being added and/or
2956 // removed.
2957 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2958 //
2959 // This class is used after the new methods have been installed in "the_class".
2960 //
2961 // So, for example, the following must be handled. Where 'm' is a method and
2962 // a number followed by an underscore is a prefix.
2963 //
2964 // Old Name New Name
2965 // Simple transfer to new method m -> m
2966 // Add prefix m -> 1_m
2967 // Remove prefix 1_m -> m
2968 // Simultaneous add of prefixes m -> 3_2_1_m
2969 // Simultaneous removal of prefixes 3_2_1_m -> m
2970 // Simultaneous add and remove 1_m -> 2_m
2971 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
2972 //
2973 class TransferNativeFunctionRegistration {
2974 private:
2975 instanceKlassHandle the_class;
2976 int prefix_count;
2977 char** prefixes;
2978
2979 // Recursively search the binary tree of possibly prefixed method names.
2980 // Iteration could be used if all agents were well behaved. Full tree walk is
2981 // more resilent to agents not cleaning up intermediate methods.
2982 // Branch at each depth in the binary tree is:
2983 // (1) without the prefix.
2984 // (2) with the prefix.
2985 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
2986 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
2987 Symbol* signature) {
2988 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
2989 if (name_symbol != NULL) {
2990 Method* method = the_class()->lookup_method(name_symbol, signature);
2991 if (method != NULL) {
2992 // Even if prefixed, intermediate methods must exist.
2993 if (method->is_native()) {
2994 // Wahoo, we found a (possibly prefixed) version of the method, return it.
2995 return method;
2996 }
2997 if (depth < prefix_count) {
2998 // Try applying further prefixes (other than this one).
2999 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3000 if (method != NULL) {
3001 return method; // found
3002 }
3003
3004 // Try adding this prefix to the method name and see if it matches
3005 // another method name.
3006 char* prefix = prefixes[depth];
3007 size_t prefix_len = strlen(prefix);
3008 size_t trial_len = name_len + prefix_len;
3009 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3010 strcpy(trial_name_str, prefix);
3011 strcat(trial_name_str, name_str);
3012 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3013 signature);
3014 if (method != NULL) {
3015 // If found along this branch, it was prefixed, mark as such
3016 method->set_is_prefixed_native();
3017 return method; // found
3018 }
3019 }
3020 }
3021 }
3022 return NULL; // This whole branch bore nothing
3023 }
3024
3025 // Return the method name with old prefixes stripped away.
3026 char* method_name_without_prefixes(Method* method) {
3027 Symbol* name = method->name();
3028 char* name_str = name->as_utf8();
3029
3030 // Old prefixing may be defunct, strip prefixes, if any.
3031 for (int i = prefix_count-1; i >= 0; i--) {
3032 char* prefix = prefixes[i];
3033 size_t prefix_len = strlen(prefix);
3034 if (strncmp(prefix, name_str, prefix_len) == 0) {
3035 name_str += prefix_len;
3036 }
3037 }
3038 return name_str;
3039 }
3040
3041 // Strip any prefixes off the old native method, then try to find a
3042 // (possibly prefixed) new native that matches it.
3043 Method* strip_and_search_for_new_native(Method* method) {
3044 ResourceMark rm;
3045 char* name_str = method_name_without_prefixes(method);
3046 return search_prefix_name_space(0, name_str, strlen(name_str),
3047 method->signature());
3048 }
3049
3050 public:
3051
3052 // Construct a native method transfer processor for this class.
3053 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3054 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3055
3056 the_class = _the_class;
3057 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3058 }
3059
3060 // Attempt to transfer any of the old or deleted methods that are native
3061 void transfer_registrations(Method** old_methods, int methods_length) {
3062 for (int j = 0; j < methods_length; j++) {
3063 Method* old_method = old_methods[j];
3064
3065 if (old_method->is_native() && old_method->has_native_function()) {
3066 Method* new_method = strip_and_search_for_new_native(old_method);
3067 if (new_method != NULL) {
3068 // Actually set the native function in the new method.
3069 // Redefine does not send events (except CFLH), certainly not this
3070 // behind the scenes re-registration.
3071 new_method->set_native_function(old_method->native_function(),
3072 !Method::native_bind_event_is_interesting);
3073 }
3074 }
3075 }
3076 }
3077 };
3078
3079 // Don't lose the association between a native method and its JNI function.
3080 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3081 TransferNativeFunctionRegistration transfer(the_class);
3082 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3083 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3084 }
3085
3086 // Deoptimize all compiled code that depends on this class.
3087 //
3088 // If the can_redefine_classes capability is obtained in the onload
3089 // phase then the compiler has recorded all dependencies from startup.
3090 // In that case we need only deoptimize and throw away all compiled code
3091 // that depends on the class.
3092 //
3093 // If can_redefine_classes is obtained sometime after the onload
3094 // phase then the dependency information may be incomplete. In that case
3095 // the first call to RedefineClasses causes all compiled code to be
3096 // thrown away. As can_redefine_classes has been obtained then
3097 // all future compilations will record dependencies so second and
3098 // subsequent calls to RedefineClasses need only throw away code
3099 // that depends on the class.
3100 //
3101 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3102 assert_locked_or_safepoint(Compile_lock);
3103
3104 // All dependencies have been recorded from startup or this is a second or
3105 // subsequent use of RedefineClasses
3106 if (JvmtiExport::all_dependencies_are_recorded()) {
3107 Universe::flush_evol_dependents_on(k_h);
3108 } else {
3109 CodeCache::mark_all_nmethods_for_deoptimization();
3110
3111 ResourceMark rm(THREAD);
3112 DeoptimizationMarker dm;
3113
3114 // Deoptimize all activations depending on marked nmethods
3115 Deoptimization::deoptimize_dependents();
3116
3117 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3118 CodeCache::make_marked_nmethods_not_entrant();
3119
3120 // From now on we know that the dependency information is complete
3121 JvmtiExport::set_all_dependencies_are_recorded(true);
3122 }
3123 }
3124
3125 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3126 Method* old_method;
3127 Method* new_method;
3128
3129 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3130 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3131 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3132 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3133
3134 _matching_methods_length = 0;
3135 _deleted_methods_length = 0;
3136 _added_methods_length = 0;
3137
3138 int nj = 0;
3139 int oj = 0;
3140 while (true) {
3141 if (oj >= _old_methods->length()) {
3142 if (nj >= _new_methods->length()) {
3143 break; // we've looked at everything, done
3144 }
3145 // New method at the end
3146 new_method = _new_methods->at(nj);
3147 _added_methods[_added_methods_length++] = new_method;
3148 ++nj;
3149 } else if (nj >= _new_methods->length()) {
3150 // Old method, at the end, is deleted
3151 old_method = _old_methods->at(oj);
3152 _deleted_methods[_deleted_methods_length++] = old_method;
3153 ++oj;
3154 } else {
3155 old_method = _old_methods->at(oj);
3156 new_method = _new_methods->at(nj);
3157 if (old_method->name() == new_method->name()) {
3158 if (old_method->signature() == new_method->signature()) {
3159 _matching_old_methods[_matching_methods_length ] = old_method;
3160 _matching_new_methods[_matching_methods_length++] = new_method;
3161 ++nj;
3162 ++oj;
3163 } else {
3164 // added overloaded have already been moved to the end,
3165 // so this is a deleted overloaded method
3166 _deleted_methods[_deleted_methods_length++] = old_method;
3167 ++oj;
3168 }
3169 } else { // names don't match
3170 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3171 // new method
3172 _added_methods[_added_methods_length++] = new_method;
3173 ++nj;
3174 } else {
3175 // deleted method
3176 _deleted_methods[_deleted_methods_length++] = old_method;
3177 ++oj;
3178 }
3179 }
3180 }
3181 }
3182 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3183 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3184 }
3185
3186
3187 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3188 instanceKlassHandle scratch_class) {
3189 // Since there is currently no rewriting of type annotations indexes
3190 // into the CP, we null out type annotations on scratch_class before
3191 // we swap annotations with the_class rather than facing the
3192 // possibility of shipping annotations with broken indexes to
3193 // Java-land.
3194 ClassLoaderData* loader_data = scratch_class->class_loader_data();
3195 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
3196 if (new_class_type_annotations != NULL) {
3197 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
3198 scratch_class->annotations()->set_class_type_annotations(NULL);
3199 }
3200 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
3201 if (new_field_type_annotations != NULL) {
3202 Annotations::free_contents(loader_data, new_field_type_annotations);
3203 scratch_class->annotations()->set_fields_type_annotations(NULL);
3204 }
3205
3206 // Swap annotation fields values
3207 Annotations* old_annotations = the_class->annotations();
3208 the_class->set_annotations(scratch_class->annotations());
3209 scratch_class->set_annotations(old_annotations);
3210 }
3211
3212
3213 // Install the redefinition of a class:
3214 // - house keeping (flushing breakpoints and caches, deoptimizing
3215 // dependent compiled code)
3216 // - replacing parts in the_class with parts from scratch_class
3217 // - adding a weak reference to track the obsolete but interesting
3218 // parts of the_class
3219 // - adjusting constant pool caches and vtables in other classes
3220 // that refer to methods in the_class. These adjustments use the
3221 // ClassLoaderDataGraph::classes_do() facility which only allows
3222 // a helper method to be specified. The interesting parameters
3223 // that we would like to pass to the helper method are saved in
3224 // static global fields in the VM operation.
3225 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3226 Klass* scratch_class_oop, TRAPS) {
3227
3228 HandleMark hm(THREAD); // make sure handles from this call are freed
3229 RC_TIMER_START(_timer_rsc_phase1);
3230
3231 instanceKlassHandle scratch_class(scratch_class_oop);
3232
3233 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3234 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3235 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3236
3237 // Remove all breakpoints in methods of this class
3238 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3239 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3240
3241 // Deoptimize all compiled code that depends on this class
3242 flush_dependent_code(the_class, THREAD);
3243
3244 _old_methods = the_class->methods();
3245 _new_methods = scratch_class->methods();
3246 _the_class_oop = the_class_oop;
3247 compute_added_deleted_matching_methods();
3248 update_jmethod_ids();
3249
3250 // Attach new constant pool to the original klass. The original
3251 // klass still refers to the old constant pool (for now).
3252 scratch_class->constants()->set_pool_holder(the_class());
3253
3254 #if 0
3255 // In theory, with constant pool merging in place we should be able
3256 // to save space by using the new, merged constant pool in place of
3257 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3258 // the klass version we are replacing now and any constant pool(s) in
3259 // previous versions of klass. Nice theory, doesn't work in practice.
3260 // When this code is enabled, even simple programs throw NullPointer
3261 // exceptions. I'm guessing that this is caused by some constant pool
3262 // cache difference between the new, merged constant pool and the
3263 // constant pool that was just being used by the klass. I'm keeping
3264 // this code around to archive the idea, but the code has to remain
3265 // disabled for now.
3266
3267 // Attach each old method to the new constant pool. This can be
3268 // done here since we are past the bytecode verification and
3269 // constant pool optimization phases.
3270 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3271 Method* method = _old_methods->at(i);
3272 method->set_constants(scratch_class->constants());
3273 }
3274
3275 {
3276 // walk all previous versions of the klass
3277 InstanceKlass *ik = (InstanceKlass *)the_class();
3278 PreviousVersionWalker pvw(ik);
3279 instanceKlassHandle ikh;
3280 do {
3281 ikh = pvw.next_previous_version();
3282 if (!ikh.is_null()) {
3283 ik = ikh();
3284
3285 // attach previous version of klass to the new constant pool
3286 ik->set_constants(scratch_class->constants());
3287
3288 // Attach each method in the previous version of klass to the
3289 // new constant pool
3290 Array<Method*>* prev_methods = ik->methods();
3291 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3292 Method* method = prev_methods->at(i);
3293 method->set_constants(scratch_class->constants());
3294 }
3295 }
3296 } while (!ikh.is_null());
3297 }
3298 #endif
3299
3300 // Replace methods and constantpool
3301 the_class->set_methods(_new_methods);
3302 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3303 // and to be able to undo operation easily.
3304
3305 ConstantPool* old_constants = the_class->constants();
3306 the_class->set_constants(scratch_class->constants());
3307 scratch_class->set_constants(old_constants); // See the previous comment.
3308 #if 0
3309 // We are swapping the guts of "the new class" with the guts of "the
3310 // class". Since the old constant pool has just been attached to "the
3311 // new class", it seems logical to set the pool holder in the old
3312 // constant pool also. However, doing this will change the observable
3313 // class hierarchy for any old methods that are still executing. A
3314 // method can query the identity of its "holder" and this query uses
3315 // the method's constant pool link to find the holder. The change in
3316 // holding class from "the class" to "the new class" can confuse
3317 // things.
3318 //
3319 // Setting the old constant pool's holder will also cause
3320 // verification done during vtable initialization below to fail.
3321 // During vtable initialization, the vtable's class is verified to be
3322 // a subtype of the method's holder. The vtable's class is "the
3323 // class" and the method's holder is gotten from the constant pool
3324 // link in the method itself. For "the class"'s directly implemented
3325 // methods, the method holder is "the class" itself (as gotten from
3326 // the new constant pool). The check works fine in this case. The
3327 // check also works fine for methods inherited from super classes.
3328 //
3329 // Miranda methods are a little more complicated. A miranda method is
3330 // provided by an interface when the class implementing the interface
3331 // does not provide its own method. These interfaces are implemented
3332 // internally as an InstanceKlass. These special instanceKlasses
3333 // share the constant pool of the class that "implements" the
3334 // interface. By sharing the constant pool, the method holder of a
3335 // miranda method is the class that "implements" the interface. In a
3336 // non-redefine situation, the subtype check works fine. However, if
3337 // the old constant pool's pool holder is modified, then the check
3338 // fails because there is no class hierarchy relationship between the
3339 // vtable's class and "the new class".
3340
3341 old_constants->set_pool_holder(scratch_class());
3342 #endif
3343
3344 // track which methods are EMCP for add_previous_version() call below
3345 BitMap emcp_methods(_old_methods->length());
3346 int emcp_method_count = 0;
3347 emcp_methods.clear(); // clears 0..(length() - 1)
3348 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3349 transfer_old_native_function_registrations(the_class);
3350
3351 // The class file bytes from before any retransformable agents mucked
3352 // with them was cached on the scratch class, move to the_class.
3353 // Note: we still want to do this if nothing needed caching since it
3354 // should get cleared in the_class too.
3355 if (the_class->get_cached_class_file_bytes() == 0) {
3356 // the_class doesn't have a cache yet so copy it
3357 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3358 }
3359 #ifndef PRODUCT
3360 else {
3361 assert(the_class->get_cached_class_file_bytes() ==
3362 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3363 assert(the_class->get_cached_class_file_len() ==
3364 scratch_class->get_cached_class_file_len(), "cache lens must match");
3365 }
3366 #endif
3367
3368 // NULL out in scratch class to not delete twice. The class to be redefined
3369 // always owns these bytes.
3370 scratch_class->set_cached_class_file(NULL);
3371
3372 // Replace inner_classes
3373 Array<u2>* old_inner_classes = the_class->inner_classes();
3374 the_class->set_inner_classes(scratch_class->inner_classes());
3375 scratch_class->set_inner_classes(old_inner_classes);
3376
3377 // Initialize the vtable and interface table after
3378 // methods have been rewritten
3379 {
3380 ResourceMark rm(THREAD);
3381 // no exception should happen here since we explicitly
3382 // do not check loader constraints.
3383 // compare_and_normalize_class_versions has already checked:
3384 // - classloaders unchanged, signatures unchanged
3385 // - all instanceKlasses for redefined classes reused & contents updated
3386 the_class->vtable()->initialize_vtable(false, THREAD);
3387 the_class->itable()->initialize_itable(false, THREAD);
3388 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3389 }
3390
3391 // Leave arrays of jmethodIDs and itable index cache unchanged
3392
3393 // Copy the "source file name" attribute from new class version
3394 the_class->set_source_file_name_index(
3395 scratch_class->source_file_name_index());
3396
3397 // Copy the "source debug extension" attribute from new class version
3398 the_class->set_source_debug_extension(
3399 scratch_class->source_debug_extension(),
3400 scratch_class->source_debug_extension() == NULL ? 0 :
3401 (int)strlen(scratch_class->source_debug_extension()));
3402
3403 // Use of javac -g could be different in the old and the new
3404 if (scratch_class->access_flags().has_localvariable_table() !=
3405 the_class->access_flags().has_localvariable_table()) {
3406
3407 AccessFlags flags = the_class->access_flags();
3408 if (scratch_class->access_flags().has_localvariable_table()) {
3409 flags.set_has_localvariable_table();
3410 } else {
3411 flags.clear_has_localvariable_table();
3412 }
3413 the_class->set_access_flags(flags);
3414 }
3415
3416 swap_annotations(the_class, scratch_class);
3417
3418 // Replace minor version number of class file
3419 u2 old_minor_version = the_class->minor_version();
3420 the_class->set_minor_version(scratch_class->minor_version());
3421 scratch_class->set_minor_version(old_minor_version);
3422
3423 // Replace major version number of class file
3424 u2 old_major_version = the_class->major_version();
3425 the_class->set_major_version(scratch_class->major_version());
3426 scratch_class->set_major_version(old_major_version);
3427
3428 // Replace CP indexes for class and name+type of enclosing method
3429 u2 old_class_idx = the_class->enclosing_method_class_index();
3430 u2 old_method_idx = the_class->enclosing_method_method_index();
3431 the_class->set_enclosing_method_indices(
3432 scratch_class->enclosing_method_class_index(),
3433 scratch_class->enclosing_method_method_index());
3434 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3435
3436 // keep track of previous versions of this class
3437 the_class->add_previous_version(scratch_class, &emcp_methods,
3438 emcp_method_count);
3439
3440 RC_TIMER_STOP(_timer_rsc_phase1);
3441 RC_TIMER_START(_timer_rsc_phase2);
3442
3443 // Adjust constantpool caches and vtables for all classes
3444 // that reference methods of the evolved class.
3445 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
3446 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
3447
3448 // JSR-292 support
3449 MemberNameTable* mnt = the_class->member_names();
3450 if (mnt != NULL) {
3451 bool trace_name_printed = false;
3452 mnt->adjust_method_entries(_matching_old_methods,
3453 _matching_new_methods,
3454 _matching_methods_length,
3455 &trace_name_printed);
3456 }
3457
3458 // Fix Resolution Error table also to remove old constant pools
3459 SystemDictionary::delete_resolution_error(old_constants);
3460
3461 if (the_class->oop_map_cache() != NULL) {
3462 // Flush references to any obsolete methods from the oop map cache
3463 // so that obsolete methods are not pinned.
3464 the_class->oop_map_cache()->flush_obsolete_entries();
3465 }
3466
3467 // increment the classRedefinedCount field in the_class and in any
3468 // direct and indirect subclasses of the_class
3469 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3470
3471 // RC_TRACE macro has an embedded ResourceMark
3472 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3473 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3474 the_class->external_name(),
3475 java_lang_Class::classRedefinedCount(the_class_mirror),
3476 os::available_memory() >> 10));
3477
3478 RC_TIMER_STOP(_timer_rsc_phase2);
3479 } // end redefine_single_class()
3480
3481
3482 // Increment the classRedefinedCount field in the specific InstanceKlass
3483 // and in all direct and indirect subclasses.
3484 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3485 oop class_mirror = ik->java_mirror();
3486 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3487 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3488 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3489
3490 if (class_oop != _the_class_oop) {
3491 // _the_class_oop count is printed at end of redefine_single_class()
3492 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3493 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3494 }
3495
3496 for (Klass *subk = ik->subklass(); subk != NULL;
3497 subk = subk->next_sibling()) {
3498 if (subk->oop_is_instance()) {
3499 // Only update instanceKlasses
3500 InstanceKlass *subik = (InstanceKlass*)subk;
3501 // recursively do subclasses of the current subclass
3502 increment_class_counter(subik, THREAD);
3503 }
3504 }
3505 }
3506
3507 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
3508 bool no_old_methods = true; // be optimistic
3509
3510 // Both array and instance classes have vtables.
3511 // a vtable should never contain old or obsolete methods
3512 ResourceMark rm(_thread);
3513 if (k->vtable_length() > 0 &&
3514 !k->vtable()->check_no_old_or_obsolete_entries()) {
3515 if (RC_TRACE_ENABLED(0x00004000)) {
3516 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3517 ("klassVtable::check_no_old_or_obsolete_entries failure"
3518 " -- OLD or OBSOLETE method found -- class: %s",
3519 k->signature_name()));
3520 k->vtable()->dump_vtable();
3521 }
3522 no_old_methods = false;
3523 }
3524
3525 if (k->oop_is_instance()) {
3526 HandleMark hm(_thread);
3527 InstanceKlass *ik = InstanceKlass::cast(k);
3528
3529 // an itable should never contain old or obsolete methods
3530 if (ik->itable_length() > 0 &&
3531 !ik->itable()->check_no_old_or_obsolete_entries()) {
3532 if (RC_TRACE_ENABLED(0x00004000)) {
3533 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3534 ("klassItable::check_no_old_or_obsolete_entries failure"
3535 " -- OLD or OBSOLETE method found -- class: %s",
3536 ik->signature_name()));
3537 ik->itable()->dump_itable();
3538 }
3539 no_old_methods = false;
3540 }
3541
3542 // the constant pool cache should never contain old or obsolete methods
3543 if (ik->constants() != NULL &&
3544 ik->constants()->cache() != NULL &&
3545 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
3546 if (RC_TRACE_ENABLED(0x00004000)) {
3547 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3548 ("cp-cache::check_no_old_or_obsolete_entries failure"
3549 " -- OLD or OBSOLETE method found -- class: %s",
3550 ik->signature_name()));
3551 ik->constants()->cache()->dump_cache();
3552 }
3553 no_old_methods = false;
3554 }
3555 }
3556
3557 // print and fail guarantee if old methods are found.
3558 if (!no_old_methods) {
3559 if (RC_TRACE_ENABLED(0x00004000)) {
3560 dump_methods();
3561 } else {
3562 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
3563 "to see more info about the following guarantee() failure.");
3564 }
3565 guarantee(false, "OLD and/or OBSOLETE method(s) found");
3566 }
3567 }
3568
3569
3570 void VM_RedefineClasses::dump_methods() {
3571 int j;
3572 RC_TRACE(0x00004000, ("_old_methods --"));
3573 for (j = 0; j < _old_methods->length(); ++j) {
3574 Method* m = _old_methods->at(j);
3575 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3576 m->access_flags().print_on(tty);
3577 tty->print(" -- ");
3578 m->print_name(tty);
3579 tty->cr();
3580 }
3581 RC_TRACE(0x00004000, ("_new_methods --"));
3582 for (j = 0; j < _new_methods->length(); ++j) {
3583 Method* m = _new_methods->at(j);
3584 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3585 m->access_flags().print_on(tty);
3586 tty->print(" -- ");
3587 m->print_name(tty);
3588 tty->cr();
3589 }
3590 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
3591 for (j = 0; j < _matching_methods_length; ++j) {
3592 Method* m = _matching_old_methods[j];
3593 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3594 m->access_flags().print_on(tty);
3595 tty->print(" -- ");
3596 m->print_name(tty);
3597 tty->cr();
3598 m = _matching_new_methods[j];
3599 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
3600 m->access_flags().print_on(tty);
3601 tty->cr();
3602 }
3603 RC_TRACE(0x00004000, ("_deleted_methods --"));
3604 for (j = 0; j < _deleted_methods_length; ++j) {
3605 Method* m = _deleted_methods[j];
3606 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3607 m->access_flags().print_on(tty);
3608 tty->print(" -- ");
3609 m->print_name(tty);
3610 tty->cr();
3611 }
3612 RC_TRACE(0x00004000, ("_added_methods --"));
3613 for (j = 0; j < _added_methods_length; ++j) {
3614 Method* m = _added_methods[j];
3615 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3616 m->access_flags().print_on(tty);
3617 tty->print(" -- ");
3618 m->print_name(tty);
3619 tty->cr();
3620 }
3621 }