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