1 /*
2 * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/metadataOnStackMark.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/verifier.hpp"
29 #include "code/codeCache.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "interpreter/oopMapCache.hpp"
32 #include "interpreter/rewriter.hpp"
33 #include "memory/gcLocker.hpp"
34 #include "memory/metadataFactory.hpp"
35 #include "memory/metaspaceShared.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/klassVtable.hpp"
39 #include "prims/jvmtiImpl.hpp"
40 #include "prims/jvmtiRedefineClasses.hpp"
41 #include "prims/methodComparator.hpp"
42 #include "runtime/deoptimization.hpp"
43 #include "runtime/relocator.hpp"
44 #include "utilities/bitMap.inline.hpp"
45 #include "utilities/events.hpp"
46
47 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
48
49 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
50 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
51 Method** VM_RedefineClasses::_matching_old_methods = NULL;
52 Method** VM_RedefineClasses::_matching_new_methods = NULL;
53 Method** VM_RedefineClasses::_deleted_methods = NULL;
54 Method** VM_RedefineClasses::_added_methods = NULL;
55 int VM_RedefineClasses::_matching_methods_length = 0;
56 int VM_RedefineClasses::_deleted_methods_length = 0;
57 int VM_RedefineClasses::_added_methods_length = 0;
58 Klass* VM_RedefineClasses::_the_class_oop = NULL;
59
60
61 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
62 const jvmtiClassDefinition *class_defs,
63 JvmtiClassLoadKind class_load_kind) {
64 _class_count = class_count;
65 _class_defs = class_defs;
66 _class_load_kind = class_load_kind;
67 _res = JVMTI_ERROR_NONE;
68 }
69
70 static inline InstanceKlass* get_ik(jclass def) {
71 oop mirror = JNIHandles::resolve_non_null(def);
72 return InstanceKlass::cast(java_lang_Class::as_Klass(mirror));
73 }
74
75 bool VM_RedefineClasses::doit_prologue() {
76 if (_class_count == 0) {
77 _res = JVMTI_ERROR_NONE;
78 return false;
79 }
80 if (_class_defs == NULL) {
81 _res = JVMTI_ERROR_NULL_POINTER;
82 return false;
83 }
84 for (int i = 0; i < _class_count; i++) {
85 if (_class_defs[i].klass == NULL) {
86 _res = JVMTI_ERROR_INVALID_CLASS;
87 return false;
88 }
89 if (_class_defs[i].class_byte_count == 0) {
90 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
91 return false;
92 }
93 if (_class_defs[i].class_bytes == NULL) {
94 _res = JVMTI_ERROR_NULL_POINTER;
95 return false;
96 }
97 }
98
99 // Start timer after all the sanity checks; not quite accurate, but
100 // better than adding a bunch of stop() calls.
101 RC_TIMER_START(_timer_vm_op_prologue);
102
103 // We first load new class versions in the prologue, because somewhere down the
104 // call chain it is required that the current thread is a Java thread.
105 _res = load_new_class_versions(Thread::current());
106 if (_res != JVMTI_ERROR_NONE) {
107 // free any successfully created classes, since none are redefined
108 for (int i = 0; i < _class_count; i++) {
109 if (_scratch_classes[i] != NULL) {
110 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
111 // Free the memory for this class at class unloading time. Not before
112 // because CMS might think this is still live.
113 InstanceKlass* ik = get_ik(_class_defs[i].klass);
114 if (ik->get_cached_class_file() == ((InstanceKlass*)_scratch_classes[i])->get_cached_class_file()) {
115 // Don't double-free cached_class_file copied from the original class if error.
116 ((InstanceKlass*)_scratch_classes[i])->set_cached_class_file(NULL);
117 }
118 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
119 }
120 }
121 // Free os::malloc allocated memory in load_new_class_version.
122 os::free(_scratch_classes);
123 RC_TIMER_STOP(_timer_vm_op_prologue);
124 return false;
125 }
126
127 RC_TIMER_STOP(_timer_vm_op_prologue);
128 return true;
129 }
130
131 void VM_RedefineClasses::doit() {
132 Thread *thread = Thread::current();
133
134 if (UseSharedSpaces) {
135 // Sharing is enabled so we remap the shared readonly space to
136 // shared readwrite, private just in case we need to redefine
137 // a shared class. We do the remap during the doit() phase of
138 // the safepoint to be safer.
139 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
140 RC_TRACE_WITH_THREAD(0x00000001, thread,
141 ("failed to remap shared readonly space to readwrite, private"));
142 _res = JVMTI_ERROR_INTERNAL;
143 return;
144 }
145 }
146
147 // Mark methods seen on stack and everywhere else so old methods are not
148 // cleaned up if they're on the stack.
149 MetadataOnStackMark md_on_stack(true);
150 HandleMark hm(thread); // make sure any handles created are deleted
151 // before the stack walk again.
152
153 for (int i = 0; i < _class_count; i++) {
154 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
155 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
156 // Free the memory for this class at class unloading time. Not before
157 // because CMS might think this is still live.
158 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
159 _scratch_classes[i] = NULL;
160 }
161
162 // Disable any dependent concurrent compilations
163 SystemDictionary::notice_modification();
164
165 // Set flag indicating that some invariants are no longer true.
166 // See jvmtiExport.hpp for detailed explanation.
167 JvmtiExport::set_has_redefined_a_class();
168
169 // check_class() is optionally called for product bits, but is
170 // always called for non-product bits.
171 #ifdef PRODUCT
172 if (RC_TRACE_ENABLED(0x00004000)) {
173 #endif
174 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
175 CheckClass check_class(thread);
176 ClassLoaderDataGraph::classes_do(&check_class);
177 #ifdef PRODUCT
178 }
179 #endif
180 }
181
182 void VM_RedefineClasses::doit_epilogue() {
183 // Free os::malloc allocated memory.
184 os::free(_scratch_classes);
185
186 // Reset the_class_oop to null for error printing.
187 _the_class_oop = NULL;
188
189 if (RC_TRACE_ENABLED(0x00000004)) {
190 // Used to have separate timers for "doit" and "all", but the timer
191 // overhead skewed the measurements.
192 jlong doit_time = _timer_rsc_phase1.milliseconds() +
193 _timer_rsc_phase2.milliseconds();
194 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
195
196 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
197 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
198 _timer_vm_op_prologue.milliseconds(), doit_time));
199 RC_TRACE(0x00000004,
200 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
201 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
202 }
203 }
204
205 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
206 // classes for primitives cannot be redefined
207 if (java_lang_Class::is_primitive(klass_mirror)) {
208 return false;
209 }
210 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
211 // classes for arrays cannot be redefined
212 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
213 return false;
214 }
215 return true;
216 }
217
218 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
219 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
220 // direct CP entries, there is just the current entry to append. For
221 // indirect and double-indirect CP entries, there are zero or more
222 // referenced CP entries along with the current entry to append.
223 // Indirect and double-indirect CP entries are handled by recursive
224 // calls to append_entry() as needed. The referenced CP entries are
225 // always appended to *merge_cp_p before the referee CP entry. These
226 // referenced CP entries may already exist in *merge_cp_p in which case
227 // there is nothing extra to append and only the current entry is
228 // appended.
229 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
230 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
231 TRAPS) {
232
233 // append is different depending on entry tag type
234 switch (scratch_cp->tag_at(scratch_i).value()) {
235
236 // The old verifier is implemented outside the VM. It loads classes,
237 // but does not resolve constant pool entries directly so we never
238 // see Class entries here with the old verifier. Similarly the old
239 // verifier does not like Class entries in the input constant pool.
240 // The split-verifier is implemented in the VM so it can optionally
241 // and directly resolve constant pool entries to load classes. The
242 // split-verifier can accept either Class entries or UnresolvedClass
243 // entries in the input constant pool. We revert the appended copy
244 // back to UnresolvedClass so that either verifier will be happy
245 // with the constant pool entry.
246 case JVM_CONSTANT_Class:
247 {
248 // revert the copy to JVM_CONSTANT_UnresolvedClass
249 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
250 scratch_cp->klass_name_at(scratch_i));
251
252 if (scratch_i != *merge_cp_length_p) {
253 // The new entry in *merge_cp_p is at a different index than
254 // the new entry in scratch_cp so we need to map the index values.
255 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
256 }
257 (*merge_cp_length_p)++;
258 } break;
259
260 // these are direct CP entries so they can be directly appended,
261 // but double and long take two constant pool entries
262 case JVM_CONSTANT_Double: // fall through
263 case JVM_CONSTANT_Long:
264 {
265 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
266 THREAD);
267
268 if (scratch_i != *merge_cp_length_p) {
269 // The new entry in *merge_cp_p is at a different index than
270 // the new entry in scratch_cp so we need to map the index values.
271 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
272 }
273 (*merge_cp_length_p) += 2;
274 } break;
275
276 // these are direct CP entries so they can be directly appended
277 case JVM_CONSTANT_Float: // fall through
278 case JVM_CONSTANT_Integer: // fall through
279 case JVM_CONSTANT_Utf8: // fall through
280
281 // This was an indirect CP entry, but it has been changed into
282 // Symbol*s so this entry can be directly appended.
283 case JVM_CONSTANT_String: // fall through
284
285 // These were indirect CP entries, but they have been changed into
286 // Symbol*s so these entries can be directly appended.
287 case JVM_CONSTANT_UnresolvedClass: // fall through
288 {
289 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
290 THREAD);
291
292 if (scratch_i != *merge_cp_length_p) {
293 // The new entry in *merge_cp_p is at a different index than
294 // the new entry in scratch_cp so we need to map the index values.
295 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
296 }
297 (*merge_cp_length_p)++;
298 } break;
299
300 // this is an indirect CP entry so it needs special handling
301 case JVM_CONSTANT_NameAndType:
302 {
303 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
304 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
305 merge_cp_length_p, THREAD);
306
307 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
308 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
309 merge_cp_p, merge_cp_length_p,
310 THREAD);
311
312 // If the referenced entries already exist in *merge_cp_p, then
313 // both new_name_ref_i and new_signature_ref_i will both be 0.
314 // In that case, all we are appending is the current entry.
315 if (new_name_ref_i != name_ref_i) {
316 RC_TRACE(0x00080000,
317 ("NameAndType entry@%d name_ref_index change: %d to %d",
318 *merge_cp_length_p, name_ref_i, new_name_ref_i));
319 }
320 if (new_signature_ref_i != signature_ref_i) {
321 RC_TRACE(0x00080000,
322 ("NameAndType entry@%d signature_ref_index change: %d to %d",
323 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
324 }
325
326 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
327 new_name_ref_i, new_signature_ref_i);
328 if (scratch_i != *merge_cp_length_p) {
329 // The new entry in *merge_cp_p is at a different index than
330 // the new entry in scratch_cp so we need to map the index values.
331 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
332 }
333 (*merge_cp_length_p)++;
334 } break;
335
336 // this is a double-indirect CP entry so it needs special handling
337 case JVM_CONSTANT_Fieldref: // fall through
338 case JVM_CONSTANT_InterfaceMethodref: // fall through
339 case JVM_CONSTANT_Methodref:
340 {
341 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
342 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
343 merge_cp_p, merge_cp_length_p, THREAD);
344
345 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
346 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
347 merge_cp_p, merge_cp_length_p, THREAD);
348
349 const char *entry_name = NULL;
350 switch (scratch_cp->tag_at(scratch_i).value()) {
351 case JVM_CONSTANT_Fieldref:
352 entry_name = "Fieldref";
353 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
354 new_name_and_type_ref_i);
355 break;
356 case JVM_CONSTANT_InterfaceMethodref:
357 entry_name = "IFMethodref";
358 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
359 new_klass_ref_i, new_name_and_type_ref_i);
360 break;
361 case JVM_CONSTANT_Methodref:
362 entry_name = "Methodref";
363 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
364 new_name_and_type_ref_i);
365 break;
366 default:
367 guarantee(false, "bad switch");
368 break;
369 }
370
371 if (klass_ref_i != new_klass_ref_i) {
372 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
373 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
374 }
375 if (name_and_type_ref_i != new_name_and_type_ref_i) {
376 RC_TRACE(0x00080000,
377 ("%s entry@%d name_and_type_index changed: %d to %d",
378 entry_name, *merge_cp_length_p, name_and_type_ref_i,
379 new_name_and_type_ref_i));
380 }
381
382 if (scratch_i != *merge_cp_length_p) {
383 // The new entry in *merge_cp_p is at a different index than
384 // the new entry in scratch_cp so we need to map the index values.
385 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
386 }
387 (*merge_cp_length_p)++;
388 } break;
389
390 // this is an indirect CP entry so it needs special handling
391 case JVM_CONSTANT_MethodType:
392 {
393 int ref_i = scratch_cp->method_type_index_at(scratch_i);
394 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
395 merge_cp_length_p, THREAD);
396 if (new_ref_i != ref_i) {
397 RC_TRACE(0x00080000,
398 ("MethodType entry@%d ref_index change: %d to %d",
399 *merge_cp_length_p, ref_i, new_ref_i));
400 }
401 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
402 if (scratch_i != *merge_cp_length_p) {
403 // The new entry in *merge_cp_p is at a different index than
404 // the new entry in scratch_cp so we need to map the index values.
405 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
406 }
407 (*merge_cp_length_p)++;
408 } break;
409
410 // this is an indirect CP entry so it needs special handling
411 case JVM_CONSTANT_MethodHandle:
412 {
413 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
414 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
415 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
416 merge_cp_length_p, THREAD);
417 if (new_ref_i != ref_i) {
418 RC_TRACE(0x00080000,
419 ("MethodHandle entry@%d ref_index change: %d to %d",
420 *merge_cp_length_p, ref_i, new_ref_i));
421 }
422 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
423 if (scratch_i != *merge_cp_length_p) {
424 // The new entry in *merge_cp_p is at a different index than
425 // the new entry in scratch_cp so we need to map the index values.
426 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
427 }
428 (*merge_cp_length_p)++;
429 } break;
430
431 // this is an indirect CP entry so it needs special handling
432 case JVM_CONSTANT_InvokeDynamic:
433 {
434 // Index of the bootstrap specifier in the operands array
435 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
436 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
437 merge_cp_length_p, THREAD);
438 // The bootstrap method NameAndType_info index
439 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
440 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
441 merge_cp_length_p, THREAD);
442 if (new_bs_i != old_bs_i) {
443 RC_TRACE(0x00080000,
444 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
445 *merge_cp_length_p, old_bs_i, new_bs_i));
446 }
447 if (new_ref_i != old_ref_i) {
448 RC_TRACE(0x00080000,
449 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
450 *merge_cp_length_p, old_ref_i, new_ref_i));
451 }
452
453 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
454 if (scratch_i != *merge_cp_length_p) {
455 // The new entry in *merge_cp_p is at a different index than
456 // the new entry in scratch_cp so we need to map the index values.
457 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
458 }
459 (*merge_cp_length_p)++;
460 } break;
461
462 // At this stage, Class or UnresolvedClass could be here, but not
463 // ClassIndex
464 case JVM_CONSTANT_ClassIndex: // fall through
465
466 // Invalid is used as the tag for the second constant pool entry
467 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
468 // not be seen by itself.
469 case JVM_CONSTANT_Invalid: // fall through
470
471 // At this stage, String could be here, but not StringIndex
472 case JVM_CONSTANT_StringIndex: // fall through
473
474 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
475 // here
476 case JVM_CONSTANT_UnresolvedClassInError: // fall through
477
478 default:
479 {
480 // leave a breadcrumb
481 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
482 ShouldNotReachHere();
483 } break;
484 } // end switch tag value
485 } // end append_entry()
486
487
488 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
489 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
490
491 int new_ref_i = ref_i;
492 bool match = (ref_i < *merge_cp_length_p) &&
493 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
494
495 if (!match) {
496 // forward reference in *merge_cp_p or not a direct match
497 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
498 if (found_i != 0) {
499 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
500 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
501 new_ref_i = found_i;
502 map_index(scratch_cp, ref_i, found_i);
503 } else {
504 // no match found so we have to append this entry to *merge_cp_p
505 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
506 // The above call to append_entry() can only append one entry
507 // so the post call query of *merge_cp_length_p is only for
508 // the sake of consistency.
509 new_ref_i = *merge_cp_length_p - 1;
510 }
511 }
512
513 return new_ref_i;
514 } // end find_or_append_indirect_entry()
515
516
517 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
518 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
519 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
520 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
521 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
522
523 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
524 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
525 merge_cp_length_p, THREAD);
526 if (new_ref_i != old_ref_i) {
527 RC_TRACE(0x00080000,
528 ("operands entry@%d bootstrap method ref_index change: %d to %d",
529 _operands_cur_length, old_ref_i, new_ref_i));
530 }
531
532 Array<u2>* merge_ops = (*merge_cp_p)->operands();
533 int new_bs_i = _operands_cur_length;
534 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
535 // However, the operand_offset_at(0) was set in the extend_operands() call.
536 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
537 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
538 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
539
540 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
541 merge_ops->at_put(new_base++, new_ref_i);
542 merge_ops->at_put(new_base++, argc);
543
544 for (int i = 0; i < argc; i++) {
545 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
546 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
547 merge_cp_length_p, THREAD);
548 merge_ops->at_put(new_base++, new_arg_ref_i);
549 if (new_arg_ref_i != old_arg_ref_i) {
550 RC_TRACE(0x00080000,
551 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
552 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
553 }
554 }
555 if (old_bs_i != _operands_cur_length) {
556 // The bootstrap specifier in *merge_cp_p is at a different index than
557 // that in scratch_cp so we need to map the index values.
558 map_operand_index(old_bs_i, new_bs_i);
559 }
560 _operands_cur_length++;
561 } // end append_operand()
562
563
564 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
565 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
566
567 int new_bs_i = old_bs_i; // bootstrap specifier index
568 bool match = (old_bs_i < _operands_cur_length) &&
569 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
570
571 if (!match) {
572 // forward reference in *merge_cp_p or not a direct match
573 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
574 _operands_cur_length, THREAD);
575 if (found_i != -1) {
576 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
577 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
578 new_bs_i = found_i;
579 map_operand_index(old_bs_i, found_i);
580 } else {
581 // no match found so we have to append this bootstrap specifier to *merge_cp_p
582 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
583 new_bs_i = _operands_cur_length - 1;
584 }
585 }
586 return new_bs_i;
587 } // end find_or_append_operand()
588
589
590 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
591 if (merge_cp->operands() == NULL) {
592 return;
593 }
594 // Shrink the merge_cp operands
595 merge_cp->shrink_operands(_operands_cur_length, CHECK);
596
597 if (RC_TRACE_ENABLED(0x00040000)) {
598 // don't want to loop unless we are tracing
599 int count = 0;
600 for (int i = 1; i < _operands_index_map_p->length(); i++) {
601 int value = _operands_index_map_p->at(i);
602 if (value != -1) {
603 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
604 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
605 count++;
606 }
607 }
608 }
609 // Clean-up
610 _operands_index_map_p = NULL;
611 _operands_cur_length = 0;
612 _operands_index_map_count = 0;
613 } // end finalize_operands_merge()
614
615
616 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
617 instanceKlassHandle the_class,
618 instanceKlassHandle scratch_class) {
619 int i;
620
621 // Check superclasses, or rather their names, since superclasses themselves can be
622 // requested to replace.
623 // Check for NULL superclass first since this might be java.lang.Object
624 if (the_class->super() != scratch_class->super() &&
625 (the_class->super() == NULL || scratch_class->super() == NULL ||
626 the_class->super()->name() !=
627 scratch_class->super()->name())) {
628 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
629 }
630
631 // Check if the number, names and order of directly implemented interfaces are the same.
632 // I think in principle we should just check if the sets of names of directly implemented
633 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
634 // .java file, also changes in .class file) should not matter. However, comparing sets is
635 // technically a bit more difficult, and, more importantly, I am not sure at present that the
636 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
637 // rely on it somewhere.
638 Array<Klass*>* k_interfaces = the_class->local_interfaces();
639 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
640 int n_intfs = k_interfaces->length();
641 if (n_intfs != k_new_interfaces->length()) {
642 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
643 }
644 for (i = 0; i < n_intfs; i++) {
645 if (k_interfaces->at(i)->name() !=
646 k_new_interfaces->at(i)->name()) {
647 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
648 }
649 }
650
651 // Check whether class is in the error init state.
652 if (the_class->is_in_error_state()) {
653 // TBD #5057930: special error code is needed in 1.6
654 return JVMTI_ERROR_INVALID_CLASS;
655 }
656
657 // Check whether class modifiers are the same.
658 jushort old_flags = (jushort) the_class->access_flags().get_flags();
659 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
660 if (old_flags != new_flags) {
661 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
662 }
663
664 // Check if the number, names, types and order of fields declared in these classes
665 // are the same.
666 JavaFieldStream old_fs(the_class);
667 JavaFieldStream new_fs(scratch_class);
668 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
669 // access
670 old_flags = old_fs.access_flags().as_short();
671 new_flags = new_fs.access_flags().as_short();
672 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
673 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
674 }
675 // offset
676 if (old_fs.offset() != new_fs.offset()) {
677 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
678 }
679 // name and signature
680 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
681 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
682 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
683 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
684 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
685 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
686 }
687 }
688
689 // If both streams aren't done then we have a differing number of
690 // fields.
691 if (!old_fs.done() || !new_fs.done()) {
692 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
693 }
694
695 // Do a parallel walk through the old and new methods. Detect
696 // cases where they match (exist in both), have been added in
697 // the new methods, or have been deleted (exist only in the
698 // old methods). The class file parser places methods in order
699 // by method name, but does not order overloaded methods by
700 // signature. In order to determine what fate befell the methods,
701 // this code places the overloaded new methods that have matching
702 // old methods in the same order as the old methods and places
703 // new overloaded methods at the end of overloaded methods of
704 // that name. The code for this order normalization is adapted
705 // from the algorithm used in InstanceKlass::find_method().
706 // Since we are swapping out of order entries as we find them,
707 // we only have to search forward through the overloaded methods.
708 // Methods which are added and have the same name as an existing
709 // method (but different signature) will be put at the end of
710 // the methods with that name, and the name mismatch code will
711 // handle them.
712 Array<Method*>* k_old_methods(the_class->methods());
713 Array<Method*>* k_new_methods(scratch_class->methods());
714 int n_old_methods = k_old_methods->length();
715 int n_new_methods = k_new_methods->length();
716 Thread* thread = Thread::current();
717
718 int ni = 0;
719 int oi = 0;
720 while (true) {
721 Method* k_old_method;
722 Method* k_new_method;
723 enum { matched, added, deleted, undetermined } method_was = undetermined;
724
725 if (oi >= n_old_methods) {
726 if (ni >= n_new_methods) {
727 break; // we've looked at everything, done
728 }
729 // New method at the end
730 k_new_method = k_new_methods->at(ni);
731 method_was = added;
732 } else if (ni >= n_new_methods) {
733 // Old method, at the end, is deleted
734 k_old_method = k_old_methods->at(oi);
735 method_was = deleted;
736 } else {
737 // There are more methods in both the old and new lists
738 k_old_method = k_old_methods->at(oi);
739 k_new_method = k_new_methods->at(ni);
740 if (k_old_method->name() != k_new_method->name()) {
741 // Methods are sorted by method name, so a mismatch means added
742 // or deleted
743 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
744 method_was = added;
745 } else {
746 method_was = deleted;
747 }
748 } else if (k_old_method->signature() == k_new_method->signature()) {
749 // Both the name and signature match
750 method_was = matched;
751 } else {
752 // The name matches, but the signature doesn't, which means we have to
753 // search forward through the new overloaded methods.
754 int nj; // outside the loop for post-loop check
755 for (nj = ni + 1; nj < n_new_methods; nj++) {
756 Method* m = k_new_methods->at(nj);
757 if (k_old_method->name() != m->name()) {
758 // reached another method name so no more overloaded methods
759 method_was = deleted;
760 break;
761 }
762 if (k_old_method->signature() == m->signature()) {
763 // found a match so swap the methods
764 k_new_methods->at_put(ni, m);
765 k_new_methods->at_put(nj, k_new_method);
766 k_new_method = m;
767 method_was = matched;
768 break;
769 }
770 }
771
772 if (nj >= n_new_methods) {
773 // reached the end without a match; so method was deleted
774 method_was = deleted;
775 }
776 }
777 }
778
779 switch (method_was) {
780 case matched:
781 // methods match, be sure modifiers do too
782 old_flags = (jushort) k_old_method->access_flags().get_flags();
783 new_flags = (jushort) k_new_method->access_flags().get_flags();
784 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
785 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
786 }
787 {
788 u2 new_num = k_new_method->method_idnum();
789 u2 old_num = k_old_method->method_idnum();
790 if (new_num != old_num) {
791 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
792 if (idnum_owner != NULL) {
793 // There is already a method assigned this idnum -- switch them
794 // Take current and original idnum from the new_method
795 idnum_owner->set_method_idnum(new_num);
796 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
797 }
798 // Take current and original idnum from the old_method
799 k_new_method->set_method_idnum(old_num);
800 k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum());
801 if (thread->has_pending_exception()) {
802 return JVMTI_ERROR_OUT_OF_MEMORY;
803 }
804 }
805 }
806 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
807 k_new_method->name_and_sig_as_C_string(), ni,
808 k_old_method->name_and_sig_as_C_string(), oi));
809 // advance to next pair of methods
810 ++oi;
811 ++ni;
812 break;
813 case added:
814 // method added, see if it is OK
815 new_flags = (jushort) k_new_method->access_flags().get_flags();
816 if ((new_flags & JVM_ACC_PRIVATE) == 0
817 // hack: private should be treated as final, but alas
818 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
819 ) {
820 // new methods must be private
821 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
822 }
823 {
824 u2 num = the_class->next_method_idnum();
825 if (num == ConstMethod::UNSET_IDNUM) {
826 // cannot add any more methods
827 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
828 }
829 u2 new_num = k_new_method->method_idnum();
830 Method* idnum_owner = scratch_class->method_with_idnum(num);
831 if (idnum_owner != NULL) {
832 // There is already a method assigned this idnum -- switch them
833 // Take current and original idnum from the new_method
834 idnum_owner->set_method_idnum(new_num);
835 idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum());
836 }
837 k_new_method->set_method_idnum(num);
838 k_new_method->set_orig_method_idnum(num);
839 if (thread->has_pending_exception()) {
840 return JVMTI_ERROR_OUT_OF_MEMORY;
841 }
842 }
843 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
844 k_new_method->name_and_sig_as_C_string(), ni));
845 ++ni; // advance to next new method
846 break;
847 case deleted:
848 // method deleted, see if it is OK
849 old_flags = (jushort) k_old_method->access_flags().get_flags();
850 if ((old_flags & JVM_ACC_PRIVATE) == 0
851 // hack: private should be treated as final, but alas
852 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
853 ) {
854 // deleted methods must be private
855 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
856 }
857 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
858 k_old_method->name_and_sig_as_C_string(), oi));
859 ++oi; // advance to next old method
860 break;
861 default:
862 ShouldNotReachHere();
863 }
864 }
865
866 return JVMTI_ERROR_NONE;
867 }
868
869
870 // Find new constant pool index value for old constant pool index value
871 // by seaching the index map. Returns zero (0) if there is no mapped
872 // value for the old constant pool index.
873 int VM_RedefineClasses::find_new_index(int old_index) {
874 if (_index_map_count == 0) {
875 // map is empty so nothing can be found
876 return 0;
877 }
878
879 if (old_index < 1 || old_index >= _index_map_p->length()) {
880 // The old_index is out of range so it is not mapped. This should
881 // not happen in regular constant pool merging use, but it can
882 // happen if a corrupt annotation is processed.
883 return 0;
884 }
885
886 int value = _index_map_p->at(old_index);
887 if (value == -1) {
888 // the old_index is not mapped
889 return 0;
890 }
891
892 return value;
893 } // end find_new_index()
894
895
896 // Find new bootstrap specifier index value for old bootstrap specifier index
897 // value by seaching the index map. Returns unused index (-1) if there is
898 // no mapped value for the old bootstrap specifier index.
899 int VM_RedefineClasses::find_new_operand_index(int old_index) {
900 if (_operands_index_map_count == 0) {
901 // map is empty so nothing can be found
902 return -1;
903 }
904
905 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
906 // The old_index is out of range so it is not mapped.
907 // This should not happen in regular constant pool merging use.
908 return -1;
909 }
910
911 int value = _operands_index_map_p->at(old_index);
912 if (value == -1) {
913 // the old_index is not mapped
914 return -1;
915 }
916
917 return value;
918 } // end find_new_operand_index()
919
920
921 // Returns true if the current mismatch is due to a resolved/unresolved
922 // class pair. Otherwise, returns false.
923 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
924 int index1, constantPoolHandle cp2, int index2) {
925
926 jbyte t1 = cp1->tag_at(index1).value();
927 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
928 return false; // wrong entry type; not our special case
929 }
930
931 jbyte t2 = cp2->tag_at(index2).value();
932 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
933 return false; // wrong entry type; not our special case
934 }
935
936 if (t1 == t2) {
937 return false; // not a mismatch; not our special case
938 }
939
940 char *s1 = cp1->klass_name_at(index1)->as_C_string();
941 char *s2 = cp2->klass_name_at(index2)->as_C_string();
942 if (strcmp(s1, s2) != 0) {
943 return false; // strings don't match; not our special case
944 }
945
946 return true; // made it through the gauntlet; this is our special case
947 } // end is_unresolved_class_mismatch()
948
949
950 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
951
952 // For consistency allocate memory using os::malloc wrapper.
953 _scratch_classes = (Klass**)
954 os::malloc(sizeof(Klass*) * _class_count, mtClass);
955 if (_scratch_classes == NULL) {
956 return JVMTI_ERROR_OUT_OF_MEMORY;
957 }
958 // Zero initialize the _scratch_classes array.
959 for (int i = 0; i < _class_count; i++) {
960 _scratch_classes[i] = NULL;
961 }
962
963 ResourceMark rm(THREAD);
964
965 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
966 // state can only be NULL if the current thread is exiting which
967 // should not happen since we're trying to do a RedefineClasses
968 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
969 for (int i = 0; i < _class_count; i++) {
970 // Create HandleMark so that any handles created while loading new class
971 // versions are deleted. Constant pools are deallocated while merging
972 // constant pools
973 HandleMark hm(THREAD);
974
975 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
976 // classes for primitives cannot be redefined
977 if (!is_modifiable_class(mirror)) {
978 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
979 }
980 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
981 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
982 Symbol* the_class_sym = the_class->name();
983
984 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
985 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
986 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
987 the_class->external_name(), _class_load_kind,
988 os::available_memory() >> 10));
989
990 ClassFileStream st((u1*) _class_defs[i].class_bytes,
991 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
992
993 // Parse the stream.
994 Handle the_class_loader(THREAD, the_class->class_loader());
995 Handle protection_domain(THREAD, the_class->protection_domain());
996 // Set redefined class handle in JvmtiThreadState class.
997 // This redefined class is sent to agent event handler for class file
998 // load hook event.
999 state->set_class_being_redefined(&the_class, _class_load_kind);
1000
1001 Klass* k = SystemDictionary::parse_stream(the_class_sym,
1002 the_class_loader,
1003 protection_domain,
1004 &st,
1005 THREAD);
1006 // Clear class_being_redefined just to be sure.
1007 state->clear_class_being_redefined();
1008
1009 // TODO: if this is retransform, and nothing changed we can skip it
1010
1011 instanceKlassHandle scratch_class (THREAD, k);
1012
1013 // Need to clean up allocated InstanceKlass if there's an error so assign
1014 // the result here. Caller deallocates all the scratch classes in case of
1015 // an error.
1016 _scratch_classes[i] = k;
1017
1018 if (HAS_PENDING_EXCEPTION) {
1019 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1020 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1021 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1022 ex_name->as_C_string()));
1023 CLEAR_PENDING_EXCEPTION;
1024
1025 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1026 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1027 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1028 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1029 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1030 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1031 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1032 // The message will be "XXX (wrong name: YYY)"
1033 return JVMTI_ERROR_NAMES_DONT_MATCH;
1034 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1035 return JVMTI_ERROR_OUT_OF_MEMORY;
1036 } else { // Just in case more exceptions can be thrown..
1037 return JVMTI_ERROR_FAILS_VERIFICATION;
1038 }
1039 }
1040
1041 // Ensure class is linked before redefine
1042 if (!the_class->is_linked()) {
1043 the_class->link_class(THREAD);
1044 if (HAS_PENDING_EXCEPTION) {
1045 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1046 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1047 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1048 ex_name->as_C_string()));
1049 CLEAR_PENDING_EXCEPTION;
1050 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1051 return JVMTI_ERROR_OUT_OF_MEMORY;
1052 } else {
1053 return JVMTI_ERROR_INTERNAL;
1054 }
1055 }
1056 }
1057
1058 // Do the validity checks in compare_and_normalize_class_versions()
1059 // before verifying the byte codes. By doing these checks first, we
1060 // limit the number of functions that require redirection from
1061 // the_class to scratch_class. In particular, we don't have to
1062 // modify JNI GetSuperclass() and thus won't change its performance.
1063 jvmtiError res = compare_and_normalize_class_versions(the_class,
1064 scratch_class);
1065 if (res != JVMTI_ERROR_NONE) {
1066 return res;
1067 }
1068
1069 // verify what the caller passed us
1070 {
1071 // The bug 6214132 caused the verification to fail.
1072 // Information about the_class and scratch_class is temporarily
1073 // recorded into jvmtiThreadState. This data is used to redirect
1074 // the_class to scratch_class in the JVM_* functions called by the
1075 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1076 // description.
1077 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1078 Verifier::verify(
1079 scratch_class, Verifier::ThrowException, true, THREAD);
1080 }
1081
1082 if (HAS_PENDING_EXCEPTION) {
1083 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1084 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1085 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1086 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1087 CLEAR_PENDING_EXCEPTION;
1088 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1089 return JVMTI_ERROR_OUT_OF_MEMORY;
1090 } else {
1091 // tell the caller the bytecodes are bad
1092 return JVMTI_ERROR_FAILS_VERIFICATION;
1093 }
1094 }
1095
1096 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1097 if (HAS_PENDING_EXCEPTION) {
1098 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1099 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1100 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1101 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1102 CLEAR_PENDING_EXCEPTION;
1103 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1104 return JVMTI_ERROR_OUT_OF_MEMORY;
1105 } else {
1106 return JVMTI_ERROR_INTERNAL;
1107 }
1108 }
1109
1110 if (VerifyMergedCPBytecodes) {
1111 // verify what we have done during constant pool merging
1112 {
1113 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1114 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1115 }
1116
1117 if (HAS_PENDING_EXCEPTION) {
1118 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1119 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1120 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1121 ("verify_byte_codes post merge-CP exception: '%s'",
1122 ex_name->as_C_string()));
1123 CLEAR_PENDING_EXCEPTION;
1124 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1125 return JVMTI_ERROR_OUT_OF_MEMORY;
1126 } else {
1127 // tell the caller that constant pool merging screwed up
1128 return JVMTI_ERROR_INTERNAL;
1129 }
1130 }
1131 }
1132
1133 Rewriter::rewrite(scratch_class, THREAD);
1134 if (!HAS_PENDING_EXCEPTION) {
1135 scratch_class->link_methods(THREAD);
1136 }
1137 if (HAS_PENDING_EXCEPTION) {
1138 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1139 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1140 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1141 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1142 CLEAR_PENDING_EXCEPTION;
1143 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1144 return JVMTI_ERROR_OUT_OF_MEMORY;
1145 } else {
1146 return JVMTI_ERROR_INTERNAL;
1147 }
1148 }
1149
1150 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1151 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1152 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1153 the_class->external_name(), os::available_memory() >> 10));
1154 }
1155
1156 return JVMTI_ERROR_NONE;
1157 }
1158
1159
1160 // Map old_index to new_index as needed. scratch_cp is only needed
1161 // for RC_TRACE() calls.
1162 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1163 int old_index, int new_index) {
1164 if (find_new_index(old_index) != 0) {
1165 // old_index is already mapped
1166 return;
1167 }
1168
1169 if (old_index == new_index) {
1170 // no mapping is needed
1171 return;
1172 }
1173
1174 _index_map_p->at_put(old_index, new_index);
1175 _index_map_count++;
1176
1177 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1178 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1179 } // end map_index()
1180
1181
1182 // Map old_index to new_index as needed.
1183 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1184 if (find_new_operand_index(old_index) != -1) {
1185 // old_index is already mapped
1186 return;
1187 }
1188
1189 if (old_index == new_index) {
1190 // no mapping is needed
1191 return;
1192 }
1193
1194 _operands_index_map_p->at_put(old_index, new_index);
1195 _operands_index_map_count++;
1196
1197 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1198 } // end map_index()
1199
1200
1201 // Merge old_cp and scratch_cp and return the results of the merge via
1202 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1203 // merge_cp_length_p. The entries in old_cp occupy the same locations
1204 // in *merge_cp_p. Also creates a map of indices from entries in
1205 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1206 // entries are only created for entries in scratch_cp that occupy a
1207 // different location in *merged_cp_p.
1208 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1209 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1210 int *merge_cp_length_p, TRAPS) {
1211
1212 if (merge_cp_p == NULL) {
1213 assert(false, "caller must provide scratch constantPool");
1214 return false; // robustness
1215 }
1216 if (merge_cp_length_p == NULL) {
1217 assert(false, "caller must provide scratch CP length");
1218 return false; // robustness
1219 }
1220 // Worst case we need old_cp->length() + scratch_cp()->length(),
1221 // but the caller might be smart so make sure we have at least
1222 // the minimum.
1223 if ((*merge_cp_p)->length() < old_cp->length()) {
1224 assert(false, "merge area too small");
1225 return false; // robustness
1226 }
1227
1228 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1229 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1230 scratch_cp->length()));
1231
1232 {
1233 // Pass 0:
1234 // The old_cp is copied to *merge_cp_p; this means that any code
1235 // using old_cp does not have to change. This work looks like a
1236 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1237 // handle one special case:
1238 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1239 // This will make verification happy.
1240
1241 int old_i; // index into old_cp
1242
1243 // index zero (0) is not used in constantPools
1244 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1245 // leave debugging crumb
1246 jbyte old_tag = old_cp->tag_at(old_i).value();
1247 switch (old_tag) {
1248 case JVM_CONSTANT_Class:
1249 case JVM_CONSTANT_UnresolvedClass:
1250 // revert the copy to JVM_CONSTANT_UnresolvedClass
1251 // May be resolving while calling this so do the same for
1252 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1253 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1254 old_cp->klass_name_at(old_i));
1255 break;
1256
1257 case JVM_CONSTANT_Double:
1258 case JVM_CONSTANT_Long:
1259 // just copy the entry to *merge_cp_p, but double and long take
1260 // two constant pool entries
1261 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1262 old_i++;
1263 break;
1264
1265 default:
1266 // just copy the entry to *merge_cp_p
1267 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1268 break;
1269 }
1270 } // end for each old_cp entry
1271
1272 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1273 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1274
1275 // We don't need to sanity check that *merge_cp_length_p is within
1276 // *merge_cp_p bounds since we have the minimum on-entry check above.
1277 (*merge_cp_length_p) = old_i;
1278 }
1279
1280 // merge_cp_len should be the same as old_cp->length() at this point
1281 // so this trace message is really a "warm-and-breathing" message.
1282 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1283 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1284
1285 int scratch_i; // index into scratch_cp
1286 {
1287 // Pass 1a:
1288 // Compare scratch_cp entries to the old_cp entries that we have
1289 // already copied to *merge_cp_p. In this pass, we are eliminating
1290 // exact duplicates (matching entry at same index) so we only
1291 // compare entries in the common indice range.
1292 int increment = 1;
1293 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1294 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1295 switch (scratch_cp->tag_at(scratch_i).value()) {
1296 case JVM_CONSTANT_Double:
1297 case JVM_CONSTANT_Long:
1298 // double and long take two constant pool entries
1299 increment = 2;
1300 break;
1301
1302 default:
1303 increment = 1;
1304 break;
1305 }
1306
1307 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1308 scratch_i, CHECK_0);
1309 if (match) {
1310 // found a match at the same index so nothing more to do
1311 continue;
1312 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1313 *merge_cp_p, scratch_i)) {
1314 // The mismatch in compare_entry_to() above is because of a
1315 // resolved versus unresolved class entry at the same index
1316 // with the same string value. Since Pass 0 reverted any
1317 // class entries to unresolved class entries in *merge_cp_p,
1318 // we go with the unresolved class entry.
1319 continue;
1320 }
1321
1322 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1323 CHECK_0);
1324 if (found_i != 0) {
1325 guarantee(found_i != scratch_i,
1326 "compare_entry_to() and find_matching_entry() do not agree");
1327
1328 // Found a matching entry somewhere else in *merge_cp_p so
1329 // just need a mapping entry.
1330 map_index(scratch_cp, scratch_i, found_i);
1331 continue;
1332 }
1333
1334 // The find_matching_entry() call above could fail to find a match
1335 // due to a resolved versus unresolved class or string entry situation
1336 // like we solved above with the is_unresolved_*_mismatch() calls.
1337 // However, we would have to call is_unresolved_*_mismatch() over
1338 // all of *merge_cp_p (potentially) and that doesn't seem to be
1339 // worth the time.
1340
1341 // No match found so we have to append this entry and any unique
1342 // referenced entries to *merge_cp_p.
1343 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1344 CHECK_0);
1345 }
1346 }
1347
1348 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1349 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1350 *merge_cp_length_p, scratch_i, _index_map_count));
1351
1352 if (scratch_i < scratch_cp->length()) {
1353 // Pass 1b:
1354 // old_cp is smaller than scratch_cp so there are entries in
1355 // scratch_cp that we have not yet processed. We take care of
1356 // those now.
1357 int increment = 1;
1358 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1359 switch (scratch_cp->tag_at(scratch_i).value()) {
1360 case JVM_CONSTANT_Double:
1361 case JVM_CONSTANT_Long:
1362 // double and long take two constant pool entries
1363 increment = 2;
1364 break;
1365
1366 default:
1367 increment = 1;
1368 break;
1369 }
1370
1371 int found_i =
1372 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1373 if (found_i != 0) {
1374 // Found a matching entry somewhere else in *merge_cp_p so
1375 // just need a mapping entry.
1376 map_index(scratch_cp, scratch_i, found_i);
1377 continue;
1378 }
1379
1380 // No match found so we have to append this entry and any unique
1381 // referenced entries to *merge_cp_p.
1382 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1383 CHECK_0);
1384 }
1385
1386 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1387 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1388 *merge_cp_length_p, scratch_i, _index_map_count));
1389 }
1390 finalize_operands_merge(*merge_cp_p, THREAD);
1391
1392 return true;
1393 } // end merge_constant_pools()
1394
1395
1396 // Scoped object to clean up the constant pool(s) created for merging
1397 class MergeCPCleaner {
1398 ClassLoaderData* _loader_data;
1399 ConstantPool* _cp;
1400 ConstantPool* _scratch_cp;
1401 public:
1402 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1403 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1404 ~MergeCPCleaner() {
1405 _loader_data->add_to_deallocate_list(_cp);
1406 if (_scratch_cp != NULL) {
1407 _loader_data->add_to_deallocate_list(_scratch_cp);
1408 }
1409 }
1410 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1411 };
1412
1413 // Merge constant pools between the_class and scratch_class and
1414 // potentially rewrite bytecodes in scratch_class to use the merged
1415 // constant pool.
1416 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1417 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1418 TRAPS) {
1419 // worst case merged constant pool length is old and new combined
1420 int merge_cp_length = the_class->constants()->length()
1421 + scratch_class->constants()->length();
1422
1423 // Constant pools are not easily reused so we allocate a new one
1424 // each time.
1425 // merge_cp is created unsafe for concurrent GC processing. It
1426 // should be marked safe before discarding it. Even though
1427 // garbage, if it crosses a card boundary, it may be scanned
1428 // in order to find the start of the first complete object on the card.
1429 ClassLoaderData* loader_data = the_class->class_loader_data();
1430 ConstantPool* merge_cp_oop =
1431 ConstantPool::allocate(loader_data,
1432 merge_cp_length,
1433 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1434 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1435
1436 HandleMark hm(THREAD); // make sure handles are cleared before
1437 // MergeCPCleaner clears out merge_cp_oop
1438 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1439
1440 // Get constants() from the old class because it could have been rewritten
1441 // while we were at a safepoint allocating a new constant pool.
1442 constantPoolHandle old_cp(THREAD, the_class->constants());
1443 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1444
1445 // If the length changed, the class was redefined out from under us. Return
1446 // an error.
1447 if (merge_cp_length != the_class->constants()->length()
1448 + scratch_class->constants()->length()) {
1449 return JVMTI_ERROR_INTERNAL;
1450 }
1451
1452 // Update the version number of the constant pool
1453 merge_cp->increment_and_save_version(old_cp->version());
1454
1455 ResourceMark rm(THREAD);
1456 _index_map_count = 0;
1457 _index_map_p = new intArray(scratch_cp->length(), -1);
1458
1459 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1460 _operands_index_map_count = 0;
1461 _operands_index_map_p = new intArray(
1462 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1463
1464 // reference to the cp holder is needed for copy_operands()
1465 merge_cp->set_pool_holder(scratch_class());
1466 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1467 &merge_cp_length, THREAD);
1468 merge_cp->set_pool_holder(NULL);
1469
1470 if (!result) {
1471 // The merge can fail due to memory allocation failure or due
1472 // to robustness checks.
1473 return JVMTI_ERROR_INTERNAL;
1474 }
1475
1476 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1477 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1478
1479 if (_index_map_count == 0) {
1480 // there is nothing to map between the new and merged constant pools
1481
1482 if (old_cp->length() == scratch_cp->length()) {
1483 // The old and new constant pools are the same length and the
1484 // index map is empty. This means that the three constant pools
1485 // are equivalent (but not the same). Unfortunately, the new
1486 // constant pool has not gone through link resolution nor have
1487 // the new class bytecodes gone through constant pool cache
1488 // rewriting so we can't use the old constant pool with the new
1489 // class.
1490
1491 // toss the merged constant pool at return
1492 } else if (old_cp->length() < scratch_cp->length()) {
1493 // The old constant pool has fewer entries than the new constant
1494 // pool and the index map is empty. This means the new constant
1495 // pool is a superset of the old constant pool. However, the old
1496 // class bytecodes have already gone through constant pool cache
1497 // rewriting so we can't use the new constant pool with the old
1498 // class.
1499
1500 // toss the merged constant pool at return
1501 } else {
1502 // The old constant pool has more entries than the new constant
1503 // pool and the index map is empty. This means that both the old
1504 // and merged constant pools are supersets of the new constant
1505 // pool.
1506
1507 // Replace the new constant pool with a shrunken copy of the
1508 // merged constant pool
1509 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1510 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1511 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1512 // It can't be cleaned up while there are handles to it.
1513 cp_cleaner.add_scratch_cp(scratch_cp());
1514 }
1515 } else {
1516 if (RC_TRACE_ENABLED(0x00040000)) {
1517 // don't want to loop unless we are tracing
1518 int count = 0;
1519 for (int i = 1; i < _index_map_p->length(); i++) {
1520 int value = _index_map_p->at(i);
1521
1522 if (value != -1) {
1523 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1524 ("index_map[%d]: old=%d new=%d", count, i, value));
1525 count++;
1526 }
1527 }
1528 }
1529
1530 // We have entries mapped between the new and merged constant pools
1531 // so we have to rewrite some constant pool references.
1532 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1533 return JVMTI_ERROR_INTERNAL;
1534 }
1535
1536 // Replace the new constant pool with a shrunken copy of the
1537 // merged constant pool so now the rewritten bytecodes have
1538 // valid references; the previous new constant pool will get
1539 // GCed.
1540 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1541 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1542 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1543 // It can't be cleaned up while there are handles to it.
1544 cp_cleaner.add_scratch_cp(scratch_cp());
1545 }
1546
1547 return JVMTI_ERROR_NONE;
1548 } // end merge_cp_and_rewrite()
1549
1550
1551 // Rewrite constant pool references in klass scratch_class.
1552 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1553 TRAPS) {
1554
1555 // rewrite constant pool references in the methods:
1556 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1557 // propagate failure back to caller
1558 return false;
1559 }
1560
1561 // rewrite constant pool references in the class_annotations:
1562 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1563 // propagate failure back to caller
1564 return false;
1565 }
1566
1567 // rewrite constant pool references in the fields_annotations:
1568 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1569 // propagate failure back to caller
1570 return false;
1571 }
1572
1573 // rewrite constant pool references in the methods_annotations:
1574 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1575 // propagate failure back to caller
1576 return false;
1577 }
1578
1579 // rewrite constant pool references in the methods_parameter_annotations:
1580 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1581 THREAD)) {
1582 // propagate failure back to caller
1583 return false;
1584 }
1585
1586 // rewrite constant pool references in the methods_default_annotations:
1587 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1588 THREAD)) {
1589 // propagate failure back to caller
1590 return false;
1591 }
1592
1593 // rewrite constant pool references in the class_type_annotations:
1594 if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) {
1595 // propagate failure back to caller
1596 return false;
1597 }
1598
1599 // rewrite constant pool references in the fields_type_annotations:
1600 if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) {
1601 // propagate failure back to caller
1602 return false;
1603 }
1604
1605 // rewrite constant pool references in the methods_type_annotations:
1606 if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) {
1607 // propagate failure back to caller
1608 return false;
1609 }
1610
1611 // There can be type annotations in the Code part of a method_info attribute.
1612 // These annotations are not accessible, even by reflection.
1613 // Currently they are not even parsed by the ClassFileParser.
1614 // If runtime access is added they will also need to be rewritten.
1615
1616 // rewrite source file name index:
1617 u2 source_file_name_idx = scratch_class->source_file_name_index();
1618 if (source_file_name_idx != 0) {
1619 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1620 if (new_source_file_name_idx != 0) {
1621 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1622 }
1623 }
1624
1625 // rewrite class generic signature index:
1626 u2 generic_signature_index = scratch_class->generic_signature_index();
1627 if (generic_signature_index != 0) {
1628 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1629 if (new_generic_signature_index != 0) {
1630 scratch_class->set_generic_signature_index(new_generic_signature_index);
1631 }
1632 }
1633
1634 return true;
1635 } // end rewrite_cp_refs()
1636
1637 // Rewrite constant pool references in the methods.
1638 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1639 instanceKlassHandle scratch_class, TRAPS) {
1640
1641 Array<Method*>* methods = scratch_class->methods();
1642
1643 if (methods == NULL || methods->length() == 0) {
1644 // no methods so nothing to do
1645 return true;
1646 }
1647
1648 // rewrite constant pool references in the methods:
1649 for (int i = methods->length() - 1; i >= 0; i--) {
1650 methodHandle method(THREAD, methods->at(i));
1651 methodHandle new_method;
1652 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1653 if (!new_method.is_null()) {
1654 // the method has been replaced so save the new method version
1655 // even in the case of an exception. original method is on the
1656 // deallocation list.
1657 methods->at_put(i, new_method());
1658 }
1659 if (HAS_PENDING_EXCEPTION) {
1660 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1661 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1662 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1663 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1664 // Need to clear pending exception here as the super caller sets
1665 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1666 CLEAR_PENDING_EXCEPTION;
1667 return false;
1668 }
1669 }
1670
1671 return true;
1672 }
1673
1674
1675 // Rewrite constant pool references in the specific method. This code
1676 // was adapted from Rewriter::rewrite_method().
1677 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1678 methodHandle *new_method_p, TRAPS) {
1679
1680 *new_method_p = methodHandle(); // default is no new method
1681
1682 // We cache a pointer to the bytecodes here in code_base. If GC
1683 // moves the Method*, then the bytecodes will also move which
1684 // will likely cause a crash. We create a No_Safepoint_Verifier
1685 // object to detect whether we pass a possible safepoint in this
1686 // code block.
1687 No_Safepoint_Verifier nsv;
1688
1689 // Bytecodes and their length
1690 address code_base = method->code_base();
1691 int code_length = method->code_size();
1692
1693 int bc_length;
1694 for (int bci = 0; bci < code_length; bci += bc_length) {
1695 address bcp = code_base + bci;
1696 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1697
1698 bc_length = Bytecodes::length_for(c);
1699 if (bc_length == 0) {
1700 // More complicated bytecodes report a length of zero so
1701 // we have to try again a slightly different way.
1702 bc_length = Bytecodes::length_at(method(), bcp);
1703 }
1704
1705 assert(bc_length != 0, "impossible bytecode length");
1706
1707 switch (c) {
1708 case Bytecodes::_ldc:
1709 {
1710 int cp_index = *(bcp + 1);
1711 int new_index = find_new_index(cp_index);
1712
1713 if (StressLdcRewrite && new_index == 0) {
1714 // If we are stressing ldc -> ldc_w rewriting, then we
1715 // always need a new_index value.
1716 new_index = cp_index;
1717 }
1718 if (new_index != 0) {
1719 // the original index is mapped so we have more work to do
1720 if (!StressLdcRewrite && new_index <= max_jubyte) {
1721 // The new value can still use ldc instead of ldc_w
1722 // unless we are trying to stress ldc -> ldc_w rewriting
1723 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1724 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1725 bcp, cp_index, new_index));
1726 *(bcp + 1) = new_index;
1727 } else {
1728 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1729 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1730 Bytecodes::name(c), bcp, cp_index, new_index));
1731 // the new value needs ldc_w instead of ldc
1732 u_char inst_buffer[4]; // max instruction size is 4 bytes
1733 bcp = (address)inst_buffer;
1734 // construct new instruction sequence
1735 *bcp = Bytecodes::_ldc_w;
1736 bcp++;
1737 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1738 // See comment below for difference between put_Java_u2()
1739 // and put_native_u2().
1740 Bytes::put_Java_u2(bcp, new_index);
1741
1742 Relocator rc(method, NULL /* no RelocatorListener needed */);
1743 methodHandle m;
1744 {
1745 Pause_No_Safepoint_Verifier pnsv(&nsv);
1746
1747 // ldc is 2 bytes and ldc_w is 3 bytes
1748 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1749 }
1750
1751 // return the new method so that the caller can update
1752 // the containing class
1753 *new_method_p = method = m;
1754 // switch our bytecode processing loop from the old method
1755 // to the new method
1756 code_base = method->code_base();
1757 code_length = method->code_size();
1758 bcp = code_base + bci;
1759 c = (Bytecodes::Code)(*bcp);
1760 bc_length = Bytecodes::length_for(c);
1761 assert(bc_length != 0, "sanity check");
1762 } // end we need ldc_w instead of ldc
1763 } // end if there is a mapped index
1764 } break;
1765
1766 // these bytecodes have a two-byte constant pool index
1767 case Bytecodes::_anewarray : // fall through
1768 case Bytecodes::_checkcast : // fall through
1769 case Bytecodes::_getfield : // fall through
1770 case Bytecodes::_getstatic : // fall through
1771 case Bytecodes::_instanceof : // fall through
1772 case Bytecodes::_invokedynamic : // fall through
1773 case Bytecodes::_invokeinterface: // fall through
1774 case Bytecodes::_invokespecial : // fall through
1775 case Bytecodes::_invokestatic : // fall through
1776 case Bytecodes::_invokevirtual : // fall through
1777 case Bytecodes::_ldc_w : // fall through
1778 case Bytecodes::_ldc2_w : // fall through
1779 case Bytecodes::_multianewarray : // fall through
1780 case Bytecodes::_new : // fall through
1781 case Bytecodes::_putfield : // fall through
1782 case Bytecodes::_putstatic :
1783 {
1784 address p = bcp + 1;
1785 int cp_index = Bytes::get_Java_u2(p);
1786 int new_index = find_new_index(cp_index);
1787 if (new_index != 0) {
1788 // the original index is mapped so update w/ new value
1789 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1790 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1791 bcp, cp_index, new_index));
1792 // Rewriter::rewrite_method() uses put_native_u2() in this
1793 // situation because it is reusing the constant pool index
1794 // location for a native index into the ConstantPoolCache.
1795 // Since we are updating the constant pool index prior to
1796 // verification and ConstantPoolCache initialization, we
1797 // need to keep the new index in Java byte order.
1798 Bytes::put_Java_u2(p, new_index);
1799 }
1800 } break;
1801 }
1802 } // end for each bytecode
1803
1804 // We also need to rewrite the parameter name indexes, if there is
1805 // method parameter data present
1806 if(method->has_method_parameters()) {
1807 const int len = method->method_parameters_length();
1808 MethodParametersElement* elem = method->method_parameters_start();
1809
1810 for (int i = 0; i < len; i++) {
1811 const u2 cp_index = elem[i].name_cp_index;
1812 const u2 new_cp_index = find_new_index(cp_index);
1813 if (new_cp_index != 0) {
1814 elem[i].name_cp_index = new_cp_index;
1815 }
1816 }
1817 }
1818 } // end rewrite_cp_refs_in_method()
1819
1820
1821 // Rewrite constant pool references in the class_annotations field.
1822 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1823 instanceKlassHandle scratch_class, TRAPS) {
1824
1825 AnnotationArray* class_annotations = scratch_class->class_annotations();
1826 if (class_annotations == NULL || class_annotations->length() == 0) {
1827 // no class_annotations so nothing to do
1828 return true;
1829 }
1830
1831 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1832 ("class_annotations length=%d", class_annotations->length()));
1833
1834 int byte_i = 0; // byte index into class_annotations
1835 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1836 THREAD);
1837 }
1838
1839
1840 // Rewrite constant pool references in an annotations typeArray. This
1841 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1842 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1843 //
1844 // annotations_typeArray {
1845 // u2 num_annotations;
1846 // annotation annotations[num_annotations];
1847 // }
1848 //
1849 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1850 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1851
1852 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1853 // not enough room for num_annotations field
1854 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1855 ("length() is too small for num_annotations field"));
1856 return false;
1857 }
1858
1859 u2 num_annotations = Bytes::get_Java_u2((address)
1860 annotations_typeArray->adr_at(byte_i_ref));
1861 byte_i_ref += 2;
1862
1863 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1864 ("num_annotations=%d", num_annotations));
1865
1866 int calc_num_annotations = 0;
1867 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1868 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1869 byte_i_ref, THREAD)) {
1870 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1871 ("bad annotation_struct at %d", calc_num_annotations));
1872 // propagate failure back to caller
1873 return false;
1874 }
1875 }
1876 assert(num_annotations == calc_num_annotations, "sanity check");
1877
1878 return true;
1879 } // end rewrite_cp_refs_in_annotations_typeArray()
1880
1881
1882 // Rewrite constant pool references in the annotation struct portion of
1883 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1884 // the 2nd-edition of the VM spec:
1885 //
1886 // struct annotation {
1887 // u2 type_index;
1888 // u2 num_element_value_pairs;
1889 // {
1890 // u2 element_name_index;
1891 // element_value value;
1892 // } element_value_pairs[num_element_value_pairs];
1893 // }
1894 //
1895 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1896 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1897 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1898 // not enough room for smallest annotation_struct
1899 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1900 ("length() is too small for annotation_struct"));
1901 return false;
1902 }
1903
1904 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1905 byte_i_ref, "mapped old type_index=%d", THREAD);
1906
1907 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1908 annotations_typeArray->adr_at(byte_i_ref));
1909 byte_i_ref += 2;
1910
1911 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1912 ("type_index=%d num_element_value_pairs=%d", type_index,
1913 num_element_value_pairs));
1914
1915 int calc_num_element_value_pairs = 0;
1916 for (; calc_num_element_value_pairs < num_element_value_pairs;
1917 calc_num_element_value_pairs++) {
1918 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1919 // not enough room for another element_name_index, let alone
1920 // the rest of another component
1921 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1922 ("length() is too small for element_name_index"));
1923 return false;
1924 }
1925
1926 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1927 annotations_typeArray, byte_i_ref,
1928 "mapped old element_name_index=%d", THREAD);
1929
1930 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1931 ("element_name_index=%d", element_name_index));
1932
1933 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1934 byte_i_ref, THREAD)) {
1935 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1936 ("bad element_value at %d", calc_num_element_value_pairs));
1937 // propagate failure back to caller
1938 return false;
1939 }
1940 } // end for each component
1941 assert(num_element_value_pairs == calc_num_element_value_pairs,
1942 "sanity check");
1943
1944 return true;
1945 } // end rewrite_cp_refs_in_annotation_struct()
1946
1947
1948 // Rewrite a constant pool reference at the current position in
1949 // annotations_typeArray if needed. Returns the original constant
1950 // pool reference if a rewrite was not needed or the new constant
1951 // pool reference if a rewrite was needed.
1952 PRAGMA_DIAG_PUSH
1953 PRAGMA_FORMAT_NONLITERAL_IGNORED
1954 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1955 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1956 const char * trace_mesg, TRAPS) {
1957
1958 address cp_index_addr = (address)
1959 annotations_typeArray->adr_at(byte_i_ref);
1960 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1961 u2 new_cp_index = find_new_index(old_cp_index);
1962 if (new_cp_index != 0) {
1963 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1964 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1965 old_cp_index = new_cp_index;
1966 }
1967 byte_i_ref += 2;
1968 return old_cp_index;
1969 }
1970 PRAGMA_DIAG_POP
1971
1972
1973 // Rewrite constant pool references in the element_value portion of an
1974 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1975 // the 2nd-edition of the VM spec:
1976 //
1977 // struct element_value {
1978 // u1 tag;
1979 // union {
1980 // u2 const_value_index;
1981 // {
1982 // u2 type_name_index;
1983 // u2 const_name_index;
1984 // } enum_const_value;
1985 // u2 class_info_index;
1986 // annotation annotation_value;
1987 // struct {
1988 // u2 num_values;
1989 // element_value values[num_values];
1990 // } array_value;
1991 // } value;
1992 // }
1993 //
1994 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1995 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1996
1997 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1998 // not enough room for a tag let alone the rest of an element_value
1999 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2000 ("length() is too small for a tag"));
2001 return false;
2002 }
2003
2004 u1 tag = annotations_typeArray->at(byte_i_ref);
2005 byte_i_ref++;
2006 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
2007
2008 switch (tag) {
2009 // These BaseType tag values are from Table 4.2 in VM spec:
2010 case 'B': // byte
2011 case 'C': // char
2012 case 'D': // double
2013 case 'F': // float
2014 case 'I': // int
2015 case 'J': // long
2016 case 'S': // short
2017 case 'Z': // boolean
2018
2019 // The remaining tag values are from Table 4.8 in the 2nd-edition of
2020 // the VM spec:
2021 case 's':
2022 {
2023 // For the above tag values (including the BaseType values),
2024 // value.const_value_index is right union field.
2025
2026 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2027 // not enough room for a const_value_index
2028 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2029 ("length() is too small for a const_value_index"));
2030 return false;
2031 }
2032
2033 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
2034 annotations_typeArray, byte_i_ref,
2035 "mapped old const_value_index=%d", THREAD);
2036
2037 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2038 ("const_value_index=%d", const_value_index));
2039 } break;
2040
2041 case 'e':
2042 {
2043 // for the above tag value, value.enum_const_value is right union field
2044
2045 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2046 // not enough room for a enum_const_value
2047 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2048 ("length() is too small for a enum_const_value"));
2049 return false;
2050 }
2051
2052 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2053 annotations_typeArray, byte_i_ref,
2054 "mapped old type_name_index=%d", THREAD);
2055
2056 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2057 annotations_typeArray, byte_i_ref,
2058 "mapped old const_name_index=%d", THREAD);
2059
2060 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2061 ("type_name_index=%d const_name_index=%d", type_name_index,
2062 const_name_index));
2063 } break;
2064
2065 case 'c':
2066 {
2067 // for the above tag value, value.class_info_index is right union field
2068
2069 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2070 // not enough room for a class_info_index
2071 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2072 ("length() is too small for a class_info_index"));
2073 return false;
2074 }
2075
2076 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2077 annotations_typeArray, byte_i_ref,
2078 "mapped old class_info_index=%d", THREAD);
2079
2080 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2081 ("class_info_index=%d", class_info_index));
2082 } break;
2083
2084 case '@':
2085 // For the above tag value, value.attr_value is the right union
2086 // field. This is a nested annotation.
2087 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2088 byte_i_ref, THREAD)) {
2089 // propagate failure back to caller
2090 return false;
2091 }
2092 break;
2093
2094 case '[':
2095 {
2096 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2097 // not enough room for a num_values field
2098 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2099 ("length() is too small for a num_values field"));
2100 return false;
2101 }
2102
2103 // For the above tag value, value.array_value is the right union
2104 // field. This is an array of nested element_value.
2105 u2 num_values = Bytes::get_Java_u2((address)
2106 annotations_typeArray->adr_at(byte_i_ref));
2107 byte_i_ref += 2;
2108 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2109
2110 int calc_num_values = 0;
2111 for (; calc_num_values < num_values; calc_num_values++) {
2112 if (!rewrite_cp_refs_in_element_value(
2113 annotations_typeArray, byte_i_ref, THREAD)) {
2114 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2115 ("bad nested element_value at %d", calc_num_values));
2116 // propagate failure back to caller
2117 return false;
2118 }
2119 }
2120 assert(num_values == calc_num_values, "sanity check");
2121 } break;
2122
2123 default:
2124 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2125 return false;
2126 } // end decode tag field
2127
2128 return true;
2129 } // end rewrite_cp_refs_in_element_value()
2130
2131
2132 // Rewrite constant pool references in a fields_annotations field.
2133 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2134 instanceKlassHandle scratch_class, TRAPS) {
2135
2136 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2137
2138 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2139 // no fields_annotations so nothing to do
2140 return true;
2141 }
2142
2143 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2144 ("fields_annotations length=%d", fields_annotations->length()));
2145
2146 for (int i = 0; i < fields_annotations->length(); i++) {
2147 AnnotationArray* field_annotations = fields_annotations->at(i);
2148 if (field_annotations == NULL || field_annotations->length() == 0) {
2149 // this field does not have any annotations so skip it
2150 continue;
2151 }
2152
2153 int byte_i = 0; // byte index into field_annotations
2154 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2155 THREAD)) {
2156 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2157 ("bad field_annotations at %d", i));
2158 // propagate failure back to caller
2159 return false;
2160 }
2161 }
2162
2163 return true;
2164 } // end rewrite_cp_refs_in_fields_annotations()
2165
2166
2167 // Rewrite constant pool references in a methods_annotations field.
2168 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2169 instanceKlassHandle scratch_class, TRAPS) {
2170
2171 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2172 Method* m = scratch_class->methods()->at(i);
2173 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2174
2175 if (method_annotations == NULL || method_annotations->length() == 0) {
2176 // this method does not have any annotations so skip it
2177 continue;
2178 }
2179
2180 int byte_i = 0; // byte index into method_annotations
2181 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2182 THREAD)) {
2183 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2184 ("bad method_annotations at %d", i));
2185 // propagate failure back to caller
2186 return false;
2187 }
2188 }
2189
2190 return true;
2191 } // end rewrite_cp_refs_in_methods_annotations()
2192
2193
2194 // Rewrite constant pool references in a methods_parameter_annotations
2195 // field. This "structure" is adapted from the
2196 // RuntimeVisibleParameterAnnotations_attribute described in section
2197 // 4.8.17 of the 2nd-edition of the VM spec:
2198 //
2199 // methods_parameter_annotations_typeArray {
2200 // u1 num_parameters;
2201 // {
2202 // u2 num_annotations;
2203 // annotation annotations[num_annotations];
2204 // } parameter_annotations[num_parameters];
2205 // }
2206 //
2207 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2208 instanceKlassHandle scratch_class, TRAPS) {
2209
2210 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2211 Method* m = scratch_class->methods()->at(i);
2212 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2213 if (method_parameter_annotations == NULL
2214 || method_parameter_annotations->length() == 0) {
2215 // this method does not have any parameter annotations so skip it
2216 continue;
2217 }
2218
2219 if (method_parameter_annotations->length() < 1) {
2220 // not enough room for a num_parameters field
2221 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2222 ("length() is too small for a num_parameters field at %d", i));
2223 return false;
2224 }
2225
2226 int byte_i = 0; // byte index into method_parameter_annotations
2227
2228 u1 num_parameters = method_parameter_annotations->at(byte_i);
2229 byte_i++;
2230
2231 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2232 ("num_parameters=%d", num_parameters));
2233
2234 int calc_num_parameters = 0;
2235 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2236 if (!rewrite_cp_refs_in_annotations_typeArray(
2237 method_parameter_annotations, byte_i, THREAD)) {
2238 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2239 ("bad method_parameter_annotations at %d", calc_num_parameters));
2240 // propagate failure back to caller
2241 return false;
2242 }
2243 }
2244 assert(num_parameters == calc_num_parameters, "sanity check");
2245 }
2246
2247 return true;
2248 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2249
2250
2251 // Rewrite constant pool references in a methods_default_annotations
2252 // field. This "structure" is adapted from the AnnotationDefault_attribute
2253 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2254 //
2255 // methods_default_annotations_typeArray {
2256 // element_value default_value;
2257 // }
2258 //
2259 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2260 instanceKlassHandle scratch_class, TRAPS) {
2261
2262 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2263 Method* m = scratch_class->methods()->at(i);
2264 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2265 if (method_default_annotations == NULL
2266 || method_default_annotations->length() == 0) {
2267 // this method does not have any default annotations so skip it
2268 continue;
2269 }
2270
2271 int byte_i = 0; // byte index into method_default_annotations
2272
2273 if (!rewrite_cp_refs_in_element_value(
2274 method_default_annotations, byte_i, THREAD)) {
2275 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2276 ("bad default element_value at %d", i));
2277 // propagate failure back to caller
2278 return false;
2279 }
2280 }
2281
2282 return true;
2283 } // end rewrite_cp_refs_in_methods_default_annotations()
2284
2285
2286 // Rewrite constant pool references in a class_type_annotations field.
2287 bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations(
2288 instanceKlassHandle scratch_class, TRAPS) {
2289
2290 AnnotationArray* class_type_annotations = scratch_class->class_type_annotations();
2291 if (class_type_annotations == NULL || class_type_annotations->length() == 0) {
2292 // no class_type_annotations so nothing to do
2293 return true;
2294 }
2295
2296 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2297 ("class_type_annotations length=%d", class_type_annotations->length()));
2298
2299 int byte_i = 0; // byte index into class_type_annotations
2300 return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations,
2301 byte_i, "ClassFile", THREAD);
2302 } // end rewrite_cp_refs_in_class_type_annotations()
2303
2304
2305 // Rewrite constant pool references in a fields_type_annotations field.
2306 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations(
2307 instanceKlassHandle scratch_class, TRAPS) {
2308
2309 Array<AnnotationArray*>* fields_type_annotations = scratch_class->fields_type_annotations();
2310 if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) {
2311 // no fields_type_annotations so nothing to do
2312 return true;
2313 }
2314
2315 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2316 ("fields_type_annotations length=%d", fields_type_annotations->length()));
2317
2318 for (int i = 0; i < fields_type_annotations->length(); i++) {
2319 AnnotationArray* field_type_annotations = fields_type_annotations->at(i);
2320 if (field_type_annotations == NULL || field_type_annotations->length() == 0) {
2321 // this field does not have any annotations so skip it
2322 continue;
2323 }
2324
2325 int byte_i = 0; // byte index into field_type_annotations
2326 if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations,
2327 byte_i, "field_info", THREAD)) {
2328 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2329 ("bad field_type_annotations at %d", i));
2330 // propagate failure back to caller
2331 return false;
2332 }
2333 }
2334
2335 return true;
2336 } // end rewrite_cp_refs_in_fields_type_annotations()
2337
2338
2339 // Rewrite constant pool references in a methods_type_annotations field.
2340 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations(
2341 instanceKlassHandle scratch_class, TRAPS) {
2342
2343 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2344 Method* m = scratch_class->methods()->at(i);
2345 AnnotationArray* method_type_annotations = m->constMethod()->type_annotations();
2346
2347 if (method_type_annotations == NULL || method_type_annotations->length() == 0) {
2348 // this method does not have any annotations so skip it
2349 continue;
2350 }
2351
2352 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2353 ("methods type_annotations length=%d", method_type_annotations->length()));
2354
2355 int byte_i = 0; // byte index into method_type_annotations
2356 if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations,
2357 byte_i, "method_info", THREAD)) {
2358 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2359 ("bad method_type_annotations at %d", i));
2360 // propagate failure back to caller
2361 return false;
2362 }
2363 }
2364
2365 return true;
2366 } // end rewrite_cp_refs_in_methods_type_annotations()
2367
2368
2369 // Rewrite constant pool references in a type_annotations
2370 // field. This "structure" is adapted from the
2371 // RuntimeVisibleTypeAnnotations_attribute described in
2372 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2373 //
2374 // type_annotations_typeArray {
2375 // u2 num_annotations;
2376 // type_annotation annotations[num_annotations];
2377 // }
2378 //
2379 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray(
2380 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2381 const char * location_mesg, TRAPS) {
2382
2383 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2384 // not enough room for num_annotations field
2385 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2386 ("length() is too small for num_annotations field"));
2387 return false;
2388 }
2389
2390 u2 num_annotations = Bytes::get_Java_u2((address)
2391 type_annotations_typeArray->adr_at(byte_i_ref));
2392 byte_i_ref += 2;
2393
2394 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2395 ("num_type_annotations=%d", num_annotations));
2396
2397 int calc_num_annotations = 0;
2398 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
2399 if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray,
2400 byte_i_ref, location_mesg, THREAD)) {
2401 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2402 ("bad type_annotation_struct at %d", calc_num_annotations));
2403 // propagate failure back to caller
2404 return false;
2405 }
2406 }
2407 assert(num_annotations == calc_num_annotations, "sanity check");
2408
2409 if (byte_i_ref != type_annotations_typeArray->length()) {
2410 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2411 ("read wrong amount of bytes at end of processing "
2412 "type_annotations_typeArray (%d of %d bytes were read)",
2413 byte_i_ref, type_annotations_typeArray->length()));
2414 return false;
2415 }
2416
2417 return true;
2418 } // end rewrite_cp_refs_in_type_annotations_typeArray()
2419
2420
2421 // Rewrite constant pool references in a type_annotation
2422 // field. This "structure" is adapted from the
2423 // RuntimeVisibleTypeAnnotations_attribute described in
2424 // section 4.7.20 of the Java SE 8 Edition of the VM spec:
2425 //
2426 // type_annotation {
2427 // u1 target_type;
2428 // union {
2429 // type_parameter_target;
2430 // supertype_target;
2431 // type_parameter_bound_target;
2432 // empty_target;
2433 // method_formal_parameter_target;
2434 // throws_target;
2435 // localvar_target;
2436 // catch_target;
2437 // offset_target;
2438 // type_argument_target;
2439 // } target_info;
2440 // type_path target_path;
2441 // annotation anno;
2442 // }
2443 //
2444 bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct(
2445 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2446 const char * location_mesg, TRAPS) {
2447
2448 if (!skip_type_annotation_target(type_annotations_typeArray,
2449 byte_i_ref, location_mesg, THREAD)) {
2450 return false;
2451 }
2452
2453 if (!skip_type_annotation_type_path(type_annotations_typeArray,
2454 byte_i_ref, THREAD)) {
2455 return false;
2456 }
2457
2458 if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray,
2459 byte_i_ref, THREAD)) {
2460 return false;
2461 }
2462
2463 return true;
2464 } // end rewrite_cp_refs_in_type_annotation_struct()
2465
2466
2467 // Read, verify and skip over the target_type and target_info part
2468 // so that rewriting can continue in the later parts of the struct.
2469 //
2470 // u1 target_type;
2471 // union {
2472 // type_parameter_target;
2473 // supertype_target;
2474 // type_parameter_bound_target;
2475 // empty_target;
2476 // method_formal_parameter_target;
2477 // throws_target;
2478 // localvar_target;
2479 // catch_target;
2480 // offset_target;
2481 // type_argument_target;
2482 // } target_info;
2483 //
2484 bool VM_RedefineClasses::skip_type_annotation_target(
2485 AnnotationArray* type_annotations_typeArray, int &byte_i_ref,
2486 const char * location_mesg, TRAPS) {
2487
2488 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2489 // not enough room for a target_type let alone the rest of a type_annotation
2490 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2491 ("length() is too small for a target_type"));
2492 return false;
2493 }
2494
2495 u1 target_type = type_annotations_typeArray->at(byte_i_ref);
2496 byte_i_ref += 1;
2497 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("target_type=0x%.2x", target_type));
2498 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("location=%s", location_mesg));
2499
2500 // Skip over target_info
2501 switch (target_type) {
2502 case 0x00:
2503 // kind: type parameter declaration of generic class or interface
2504 // location: ClassFile
2505 case 0x01:
2506 // kind: type parameter declaration of generic method or constructor
2507 // location: method_info
2508
2509 {
2510 // struct:
2511 // type_parameter_target {
2512 // u1 type_parameter_index;
2513 // }
2514 //
2515 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2516 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2517 ("length() is too small for a type_parameter_target"));
2518 return false;
2519 }
2520
2521 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2522 byte_i_ref += 1;
2523
2524 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2525 ("type_parameter_target: type_parameter_index=%d",
2526 type_parameter_index));
2527 } break;
2528
2529 case 0x10:
2530 // kind: type in extends clause of class or interface declaration
2531 // (including the direct superclass of an anonymous class declaration),
2532 // or in implements clause of interface declaration
2533 // location: ClassFile
2534
2535 {
2536 // struct:
2537 // supertype_target {
2538 // u2 supertype_index;
2539 // }
2540 //
2541 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2542 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2543 ("length() is too small for a supertype_target"));
2544 return false;
2545 }
2546
2547 u2 supertype_index = Bytes::get_Java_u2((address)
2548 type_annotations_typeArray->adr_at(byte_i_ref));
2549 byte_i_ref += 2;
2550
2551 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2552 ("supertype_target: supertype_index=%d", supertype_index));
2553 } break;
2554
2555 case 0x11:
2556 // kind: type in bound of type parameter declaration of generic class or interface
2557 // location: ClassFile
2558 case 0x12:
2559 // kind: type in bound of type parameter declaration of generic method or constructor
2560 // location: method_info
2561
2562 {
2563 // struct:
2564 // type_parameter_bound_target {
2565 // u1 type_parameter_index;
2566 // u1 bound_index;
2567 // }
2568 //
2569 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2570 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2571 ("length() is too small for a type_parameter_bound_target"));
2572 return false;
2573 }
2574
2575 u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2576 byte_i_ref += 1;
2577 u1 bound_index = type_annotations_typeArray->at(byte_i_ref);
2578 byte_i_ref += 1;
2579
2580 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2581 ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d",
2582 type_parameter_index, bound_index));
2583 } break;
2584
2585 case 0x13:
2586 // kind: type in field declaration
2587 // location: field_info
2588 case 0x14:
2589 // kind: return type of method, or type of newly constructed object
2590 // location: method_info
2591 case 0x15:
2592 // kind: receiver type of method or constructor
2593 // location: method_info
2594
2595 {
2596 // struct:
2597 // empty_target {
2598 // }
2599 //
2600 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2601 ("empty_target"));
2602 } break;
2603
2604 case 0x16:
2605 // kind: type in formal parameter declaration of method, constructor, or lambda expression
2606 // location: method_info
2607
2608 {
2609 // struct:
2610 // formal_parameter_target {
2611 // u1 formal_parameter_index;
2612 // }
2613 //
2614 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2615 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2616 ("length() is too small for a formal_parameter_target"));
2617 return false;
2618 }
2619
2620 u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref);
2621 byte_i_ref += 1;
2622
2623 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2624 ("formal_parameter_target: formal_parameter_index=%d",
2625 formal_parameter_index));
2626 } break;
2627
2628 case 0x17:
2629 // kind: type in throws clause of method or constructor
2630 // location: method_info
2631
2632 {
2633 // struct:
2634 // throws_target {
2635 // u2 throws_type_index
2636 // }
2637 //
2638 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2639 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2640 ("length() is too small for a throws_target"));
2641 return false;
2642 }
2643
2644 u2 throws_type_index = Bytes::get_Java_u2((address)
2645 type_annotations_typeArray->adr_at(byte_i_ref));
2646 byte_i_ref += 2;
2647
2648 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2649 ("throws_target: throws_type_index=%d", throws_type_index));
2650 } break;
2651
2652 case 0x40:
2653 // kind: type in local variable declaration
2654 // location: Code
2655 case 0x41:
2656 // kind: type in resource variable declaration
2657 // location: Code
2658
2659 {
2660 // struct:
2661 // localvar_target {
2662 // u2 table_length;
2663 // struct {
2664 // u2 start_pc;
2665 // u2 length;
2666 // u2 index;
2667 // } table[table_length];
2668 // }
2669 //
2670 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2671 // not enough room for a table_length let alone the rest of a localvar_target
2672 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2673 ("length() is too small for a localvar_target table_length"));
2674 return false;
2675 }
2676
2677 u2 table_length = Bytes::get_Java_u2((address)
2678 type_annotations_typeArray->adr_at(byte_i_ref));
2679 byte_i_ref += 2;
2680
2681 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2682 ("localvar_target: table_length=%d", table_length));
2683
2684 int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry
2685 int table_size = table_length * table_struct_size;
2686
2687 if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) {
2688 // not enough room for a table
2689 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2690 ("length() is too small for a table array of length %d", table_length));
2691 return false;
2692 }
2693
2694 // Skip over table
2695 byte_i_ref += table_size;
2696 } break;
2697
2698 case 0x42:
2699 // kind: type in exception parameter declaration
2700 // location: Code
2701
2702 {
2703 // struct:
2704 // catch_target {
2705 // u2 exception_table_index;
2706 // }
2707 //
2708 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2709 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2710 ("length() is too small for a catch_target"));
2711 return false;
2712 }
2713
2714 u2 exception_table_index = Bytes::get_Java_u2((address)
2715 type_annotations_typeArray->adr_at(byte_i_ref));
2716 byte_i_ref += 2;
2717
2718 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2719 ("catch_target: exception_table_index=%d", exception_table_index));
2720 } break;
2721
2722 case 0x43:
2723 // kind: type in instanceof expression
2724 // location: Code
2725 case 0x44:
2726 // kind: type in new expression
2727 // location: Code
2728 case 0x45:
2729 // kind: type in method reference expression using ::new
2730 // location: Code
2731 case 0x46:
2732 // kind: type in method reference expression using ::Identifier
2733 // location: Code
2734
2735 {
2736 // struct:
2737 // offset_target {
2738 // u2 offset;
2739 // }
2740 //
2741 if ((byte_i_ref + 2) > type_annotations_typeArray->length()) {
2742 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2743 ("length() is too small for a offset_target"));
2744 return false;
2745 }
2746
2747 u2 offset = Bytes::get_Java_u2((address)
2748 type_annotations_typeArray->adr_at(byte_i_ref));
2749 byte_i_ref += 2;
2750
2751 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2752 ("offset_target: offset=%d", offset));
2753 } break;
2754
2755 case 0x47:
2756 // kind: type in cast expression
2757 // location: Code
2758 case 0x48:
2759 // kind: type argument for generic constructor in new expression or
2760 // explicit constructor invocation statement
2761 // location: Code
2762 case 0x49:
2763 // kind: type argument for generic method in method invocation expression
2764 // location: Code
2765 case 0x4A:
2766 // kind: type argument for generic constructor in method reference expression using ::new
2767 // location: Code
2768 case 0x4B:
2769 // kind: type argument for generic method in method reference expression using ::Identifier
2770 // location: Code
2771
2772 {
2773 // struct:
2774 // type_argument_target {
2775 // u2 offset;
2776 // u1 type_argument_index;
2777 // }
2778 //
2779 if ((byte_i_ref + 3) > type_annotations_typeArray->length()) {
2780 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2781 ("length() is too small for a type_argument_target"));
2782 return false;
2783 }
2784
2785 u2 offset = Bytes::get_Java_u2((address)
2786 type_annotations_typeArray->adr_at(byte_i_ref));
2787 byte_i_ref += 2;
2788 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2789 byte_i_ref += 1;
2790
2791 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2792 ("type_argument_target: offset=%d, type_argument_index=%d",
2793 offset, type_argument_index));
2794 } break;
2795
2796 default:
2797 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2798 ("unknown target_type"));
2799 #ifdef ASSERT
2800 ShouldNotReachHere();
2801 #endif
2802 return false;
2803 }
2804
2805 return true;
2806 } // end skip_type_annotation_target()
2807
2808
2809 // Read, verify and skip over the type_path part so that rewriting
2810 // can continue in the later parts of the struct.
2811 //
2812 // type_path {
2813 // u1 path_length;
2814 // {
2815 // u1 type_path_kind;
2816 // u1 type_argument_index;
2817 // } path[path_length];
2818 // }
2819 //
2820 bool VM_RedefineClasses::skip_type_annotation_type_path(
2821 AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) {
2822
2823 if ((byte_i_ref + 1) > type_annotations_typeArray->length()) {
2824 // not enough room for a path_length let alone the rest of the type_path
2825 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2826 ("length() is too small for a type_path"));
2827 return false;
2828 }
2829
2830 u1 path_length = type_annotations_typeArray->at(byte_i_ref);
2831 byte_i_ref += 1;
2832
2833 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2834 ("type_path: path_length=%d", path_length));
2835
2836 int calc_path_length = 0;
2837 for (; calc_path_length < path_length; calc_path_length++) {
2838 if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) {
2839 // not enough room for a path
2840 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2841 ("length() is too small for path entry %d of %d",
2842 calc_path_length, path_length));
2843 return false;
2844 }
2845
2846 u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref);
2847 byte_i_ref += 1;
2848 u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref);
2849 byte_i_ref += 1;
2850
2851 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2852 ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d",
2853 calc_path_length, type_path_kind, type_argument_index));
2854
2855 if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) {
2856 // not enough room for a path
2857 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2858 ("inconsistent type_path values"));
2859 return false;
2860 }
2861 }
2862 assert(path_length == calc_path_length, "sanity check");
2863
2864 return true;
2865 } // end skip_type_annotation_type_path()
2866
2867
2868 // Rewrite constant pool references in the method's stackmap table.
2869 // These "structures" are adapted from the StackMapTable_attribute that
2870 // is described in section 4.8.4 of the 6.0 version of the VM spec
2871 // (dated 2005.10.26):
2872 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2873 //
2874 // stack_map {
2875 // u2 number_of_entries;
2876 // stack_map_frame entries[number_of_entries];
2877 // }
2878 //
2879 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2880 methodHandle method, TRAPS) {
2881
2882 if (!method->has_stackmap_table()) {
2883 return;
2884 }
2885
2886 AnnotationArray* stackmap_data = method->stackmap_data();
2887 address stackmap_p = (address)stackmap_data->adr_at(0);
2888 address stackmap_end = stackmap_p + stackmap_data->length();
2889
2890 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2891 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2892 stackmap_p += 2;
2893
2894 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2895 ("number_of_entries=%u", number_of_entries));
2896
2897 // walk through each stack_map_frame
2898 u2 calc_number_of_entries = 0;
2899 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2900 // The stack_map_frame structure is a u1 frame_type followed by
2901 // 0 or more bytes of data:
2902 //
2903 // union stack_map_frame {
2904 // same_frame;
2905 // same_locals_1_stack_item_frame;
2906 // same_locals_1_stack_item_frame_extended;
2907 // chop_frame;
2908 // same_frame_extended;
2909 // append_frame;
2910 // full_frame;
2911 // }
2912
2913 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2914 // The Linux compiler does not like frame_type to be u1 or u2. It
2915 // issues the following warning for the first if-statement below:
2916 //
2917 // "warning: comparison is always true due to limited range of data type"
2918 //
2919 u4 frame_type = *stackmap_p;
2920 stackmap_p++;
2921
2922 // same_frame {
2923 // u1 frame_type = SAME; /* 0-63 */
2924 // }
2925 if (frame_type >= 0 && frame_type <= 63) {
2926 // nothing more to do for same_frame
2927 }
2928
2929 // same_locals_1_stack_item_frame {
2930 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2931 // verification_type_info stack[1];
2932 // }
2933 else if (frame_type >= 64 && frame_type <= 127) {
2934 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2935 calc_number_of_entries, frame_type, THREAD);
2936 }
2937
2938 // reserved for future use
2939 else if (frame_type >= 128 && frame_type <= 246) {
2940 // nothing more to do for reserved frame_types
2941 }
2942
2943 // same_locals_1_stack_item_frame_extended {
2944 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2945 // u2 offset_delta;
2946 // verification_type_info stack[1];
2947 // }
2948 else if (frame_type == 247) {
2949 stackmap_p += 2;
2950 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2951 calc_number_of_entries, frame_type, THREAD);
2952 }
2953
2954 // chop_frame {
2955 // u1 frame_type = CHOP; /* 248-250 */
2956 // u2 offset_delta;
2957 // }
2958 else if (frame_type >= 248 && frame_type <= 250) {
2959 stackmap_p += 2;
2960 }
2961
2962 // same_frame_extended {
2963 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2964 // u2 offset_delta;
2965 // }
2966 else if (frame_type == 251) {
2967 stackmap_p += 2;
2968 }
2969
2970 // append_frame {
2971 // u1 frame_type = APPEND; /* 252-254 */
2972 // u2 offset_delta;
2973 // verification_type_info locals[frame_type - 251];
2974 // }
2975 else if (frame_type >= 252 && frame_type <= 254) {
2976 assert(stackmap_p + 2 <= stackmap_end,
2977 "no room for offset_delta");
2978 stackmap_p += 2;
2979 u1 len = frame_type - 251;
2980 for (u1 i = 0; i < len; i++) {
2981 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2982 calc_number_of_entries, frame_type, THREAD);
2983 }
2984 }
2985
2986 // full_frame {
2987 // u1 frame_type = FULL_FRAME; /* 255 */
2988 // u2 offset_delta;
2989 // u2 number_of_locals;
2990 // verification_type_info locals[number_of_locals];
2991 // u2 number_of_stack_items;
2992 // verification_type_info stack[number_of_stack_items];
2993 // }
2994 else if (frame_type == 255) {
2995 assert(stackmap_p + 2 + 2 <= stackmap_end,
2996 "no room for smallest full_frame");
2997 stackmap_p += 2;
2998
2999 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
3000 stackmap_p += 2;
3001
3002 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
3003 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3004 calc_number_of_entries, frame_type, THREAD);
3005 }
3006
3007 // Use the largest size for the number_of_stack_items, but only get
3008 // the right number of bytes.
3009 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
3010 stackmap_p += 2;
3011
3012 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
3013 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
3014 calc_number_of_entries, frame_type, THREAD);
3015 }
3016 }
3017 } // end while there is a stack_map_frame
3018 assert(number_of_entries == calc_number_of_entries, "sanity check");
3019 } // end rewrite_cp_refs_in_stack_map_table()
3020
3021
3022 // Rewrite constant pool references in the verification type info
3023 // portion of the method's stackmap table. These "structures" are
3024 // adapted from the StackMapTable_attribute that is described in
3025 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
3026 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
3027 //
3028 // The verification_type_info structure is a u1 tag followed by 0 or
3029 // more bytes of data:
3030 //
3031 // union verification_type_info {
3032 // Top_variable_info;
3033 // Integer_variable_info;
3034 // Float_variable_info;
3035 // Long_variable_info;
3036 // Double_variable_info;
3037 // Null_variable_info;
3038 // UninitializedThis_variable_info;
3039 // Object_variable_info;
3040 // Uninitialized_variable_info;
3041 // }
3042 //
3043 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
3044 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
3045 u1 frame_type, TRAPS) {
3046
3047 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
3048 u1 tag = *stackmap_p_ref;
3049 stackmap_p_ref++;
3050
3051 switch (tag) {
3052 // Top_variable_info {
3053 // u1 tag = ITEM_Top; /* 0 */
3054 // }
3055 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
3056 case 0: // fall through
3057
3058 // Integer_variable_info {
3059 // u1 tag = ITEM_Integer; /* 1 */
3060 // }
3061 case ITEM_Integer: // fall through
3062
3063 // Float_variable_info {
3064 // u1 tag = ITEM_Float; /* 2 */
3065 // }
3066 case ITEM_Float: // fall through
3067
3068 // Double_variable_info {
3069 // u1 tag = ITEM_Double; /* 3 */
3070 // }
3071 case ITEM_Double: // fall through
3072
3073 // Long_variable_info {
3074 // u1 tag = ITEM_Long; /* 4 */
3075 // }
3076 case ITEM_Long: // fall through
3077
3078 // Null_variable_info {
3079 // u1 tag = ITEM_Null; /* 5 */
3080 // }
3081 case ITEM_Null: // fall through
3082
3083 // UninitializedThis_variable_info {
3084 // u1 tag = ITEM_UninitializedThis; /* 6 */
3085 // }
3086 case ITEM_UninitializedThis:
3087 // nothing more to do for the above tag types
3088 break;
3089
3090 // Object_variable_info {
3091 // u1 tag = ITEM_Object; /* 7 */
3092 // u2 cpool_index;
3093 // }
3094 case ITEM_Object:
3095 {
3096 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
3097 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
3098 u2 new_cp_index = find_new_index(cpool_index);
3099 if (new_cp_index != 0) {
3100 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3101 ("mapped old cpool_index=%d", cpool_index));
3102 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
3103 cpool_index = new_cp_index;
3104 }
3105 stackmap_p_ref += 2;
3106
3107 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3108 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
3109 frame_type, cpool_index));
3110 } break;
3111
3112 // Uninitialized_variable_info {
3113 // u1 tag = ITEM_Uninitialized; /* 8 */
3114 // u2 offset;
3115 // }
3116 case ITEM_Uninitialized:
3117 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
3118 stackmap_p_ref += 2;
3119 break;
3120
3121 default:
3122 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
3123 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
3124 ShouldNotReachHere();
3125 break;
3126 } // end switch (tag)
3127 } // end rewrite_cp_refs_in_verification_type_info()
3128
3129
3130 // Change the constant pool associated with klass scratch_class to
3131 // scratch_cp. If shrink is true, then scratch_cp_length elements
3132 // are copied from scratch_cp to a smaller constant pool and the
3133 // smaller constant pool is associated with scratch_class.
3134 void VM_RedefineClasses::set_new_constant_pool(
3135 ClassLoaderData* loader_data,
3136 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
3137 int scratch_cp_length, TRAPS) {
3138 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
3139
3140 // scratch_cp is a merged constant pool and has enough space for a
3141 // worst case merge situation. We want to associate the minimum
3142 // sized constant pool with the klass to save space.
3143 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
3144 constantPoolHandle smaller_cp(THREAD, cp);
3145
3146 // preserve version() value in the smaller copy
3147 int version = scratch_cp->version();
3148 assert(version != 0, "sanity check");
3149 smaller_cp->set_version(version);
3150
3151 // attach klass to new constant pool
3152 // reference to the cp holder is needed for copy_operands()
3153 smaller_cp->set_pool_holder(scratch_class());
3154
3155 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
3156 if (HAS_PENDING_EXCEPTION) {
3157 // Exception is handled in the caller
3158 loader_data->add_to_deallocate_list(smaller_cp());
3159 return;
3160 }
3161 scratch_cp = smaller_cp;
3162
3163 // attach new constant pool to klass
3164 scratch_class->set_constants(scratch_cp());
3165
3166 int i; // for portability
3167
3168 // update each field in klass to use new constant pool indices as needed
3169 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
3170 jshort cur_index = fs.name_index();
3171 jshort new_index = find_new_index(cur_index);
3172 if (new_index != 0) {
3173 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3174 ("field-name_index change: %d to %d", cur_index, new_index));
3175 fs.set_name_index(new_index);
3176 }
3177 cur_index = fs.signature_index();
3178 new_index = find_new_index(cur_index);
3179 if (new_index != 0) {
3180 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3181 ("field-signature_index change: %d to %d", cur_index, new_index));
3182 fs.set_signature_index(new_index);
3183 }
3184 cur_index = fs.initval_index();
3185 new_index = find_new_index(cur_index);
3186 if (new_index != 0) {
3187 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3188 ("field-initval_index change: %d to %d", cur_index, new_index));
3189 fs.set_initval_index(new_index);
3190 }
3191 cur_index = fs.generic_signature_index();
3192 new_index = find_new_index(cur_index);
3193 if (new_index != 0) {
3194 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3195 ("field-generic_signature change: %d to %d", cur_index, new_index));
3196 fs.set_generic_signature_index(new_index);
3197 }
3198 } // end for each field
3199
3200 // Update constant pool indices in the inner classes info to use
3201 // new constant indices as needed. The inner classes info is a
3202 // quadruple:
3203 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
3204 InnerClassesIterator iter(scratch_class);
3205 for (; !iter.done(); iter.next()) {
3206 int cur_index = iter.inner_class_info_index();
3207 if (cur_index == 0) {
3208 continue; // JVM spec. allows null inner class refs so skip it
3209 }
3210 int new_index = find_new_index(cur_index);
3211 if (new_index != 0) {
3212 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3213 ("inner_class_info change: %d to %d", cur_index, new_index));
3214 iter.set_inner_class_info_index(new_index);
3215 }
3216 cur_index = iter.outer_class_info_index();
3217 new_index = find_new_index(cur_index);
3218 if (new_index != 0) {
3219 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3220 ("outer_class_info change: %d to %d", cur_index, new_index));
3221 iter.set_outer_class_info_index(new_index);
3222 }
3223 cur_index = iter.inner_name_index();
3224 new_index = find_new_index(cur_index);
3225 if (new_index != 0) {
3226 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3227 ("inner_name change: %d to %d", cur_index, new_index));
3228 iter.set_inner_name_index(new_index);
3229 }
3230 } // end for each inner class
3231
3232 // Attach each method in klass to the new constant pool and update
3233 // to use new constant pool indices as needed:
3234 Array<Method*>* methods = scratch_class->methods();
3235 for (i = methods->length() - 1; i >= 0; i--) {
3236 methodHandle method(THREAD, methods->at(i));
3237 method->set_constants(scratch_cp());
3238
3239 int new_index = find_new_index(method->name_index());
3240 if (new_index != 0) {
3241 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3242 ("method-name_index change: %d to %d", method->name_index(),
3243 new_index));
3244 method->set_name_index(new_index);
3245 }
3246 new_index = find_new_index(method->signature_index());
3247 if (new_index != 0) {
3248 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3249 ("method-signature_index change: %d to %d",
3250 method->signature_index(), new_index));
3251 method->set_signature_index(new_index);
3252 }
3253 new_index = find_new_index(method->generic_signature_index());
3254 if (new_index != 0) {
3255 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3256 ("method-generic_signature_index change: %d to %d",
3257 method->generic_signature_index(), new_index));
3258 method->set_generic_signature_index(new_index);
3259 }
3260
3261 // Update constant pool indices in the method's checked exception
3262 // table to use new constant indices as needed.
3263 int cext_length = method->checked_exceptions_length();
3264 if (cext_length > 0) {
3265 CheckedExceptionElement * cext_table =
3266 method->checked_exceptions_start();
3267 for (int j = 0; j < cext_length; j++) {
3268 int cur_index = cext_table[j].class_cp_index;
3269 int new_index = find_new_index(cur_index);
3270 if (new_index != 0) {
3271 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3272 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
3273 cext_table[j].class_cp_index = (u2)new_index;
3274 }
3275 } // end for each checked exception table entry
3276 } // end if there are checked exception table entries
3277
3278 // Update each catch type index in the method's exception table
3279 // to use new constant pool indices as needed. The exception table
3280 // holds quadruple entries of the form:
3281 // (beg_bci, end_bci, handler_bci, klass_index)
3282
3283 ExceptionTable ex_table(method());
3284 int ext_length = ex_table.length();
3285
3286 for (int j = 0; j < ext_length; j ++) {
3287 int cur_index = ex_table.catch_type_index(j);
3288 int new_index = find_new_index(cur_index);
3289 if (new_index != 0) {
3290 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3291 ("ext-klass_index change: %d to %d", cur_index, new_index));
3292 ex_table.set_catch_type_index(j, new_index);
3293 }
3294 } // end for each exception table entry
3295
3296 // Update constant pool indices in the method's local variable
3297 // table to use new constant indices as needed. The local variable
3298 // table hold sextuple entries of the form:
3299 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
3300 int lvt_length = method->localvariable_table_length();
3301 if (lvt_length > 0) {
3302 LocalVariableTableElement * lv_table =
3303 method->localvariable_table_start();
3304 for (int j = 0; j < lvt_length; j++) {
3305 int cur_index = lv_table[j].name_cp_index;
3306 int new_index = find_new_index(cur_index);
3307 if (new_index != 0) {
3308 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3309 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
3310 lv_table[j].name_cp_index = (u2)new_index;
3311 }
3312 cur_index = lv_table[j].descriptor_cp_index;
3313 new_index = find_new_index(cur_index);
3314 if (new_index != 0) {
3315 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3316 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
3317 new_index));
3318 lv_table[j].descriptor_cp_index = (u2)new_index;
3319 }
3320 cur_index = lv_table[j].signature_cp_index;
3321 new_index = find_new_index(cur_index);
3322 if (new_index != 0) {
3323 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
3324 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
3325 lv_table[j].signature_cp_index = (u2)new_index;
3326 }
3327 } // end for each local variable table entry
3328 } // end if there are local variable table entries
3329
3330 rewrite_cp_refs_in_stack_map_table(method, THREAD);
3331 } // end for each method
3332 } // end set_new_constant_pool()
3333
3334
3335 // Unevolving classes may point to methods of the_class directly
3336 // from their constant pool caches, itables, and/or vtables. We
3337 // use the ClassLoaderDataGraph::classes_do() facility and this helper
3338 // to fix up these pointers.
3339
3340 // Adjust cpools and vtables closure
3341 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
3342
3343 // This is a very busy routine. We don't want too much tracing
3344 // printed out.
3345 bool trace_name_printed = false;
3346 InstanceKlass *the_class = InstanceKlass::cast(_the_class_oop);
3347
3348 // Very noisy: only enable this call if you are trying to determine
3349 // that a specific class gets found by this routine.
3350 // RC_TRACE macro has an embedded ResourceMark
3351 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
3352 // ("adjust check: name=%s", k->external_name()));
3353 // trace_name_printed = true;
3354
3355 // If the class being redefined is java.lang.Object, we need to fix all
3356 // array class vtables also
3357 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
3358 k->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3359
3360 } else if (k->oop_is_instance()) {
3361 HandleMark hm(_thread);
3362 InstanceKlass *ik = InstanceKlass::cast(k);
3363
3364 // HotSpot specific optimization! HotSpot does not currently
3365 // support delegation from the bootstrap class loader to a
3366 // user-defined class loader. This means that if the bootstrap
3367 // class loader is the initiating class loader, then it will also
3368 // be the defining class loader. This also means that classes
3369 // loaded by the bootstrap class loader cannot refer to classes
3370 // loaded by a user-defined class loader. Note: a user-defined
3371 // class loader can delegate to the bootstrap class loader.
3372 //
3373 // If the current class being redefined has a user-defined class
3374 // loader as its defining class loader, then we can skip all
3375 // classes loaded by the bootstrap class loader.
3376 bool is_user_defined =
3377 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
3378 if (is_user_defined && ik->class_loader() == NULL) {
3379 return;
3380 }
3381
3382 // Fix the vtable embedded in the_class and subclasses of the_class,
3383 // if one exists. We discard scratch_class and we don't keep an
3384 // InstanceKlass around to hold obsolete methods so we don't have
3385 // any other InstanceKlass embedded vtables to update. The vtable
3386 // holds the Method*s for virtual (but not final) methods.
3387 // Default methods, or concrete methods in interfaces are stored
3388 // in the vtable, so if an interface changes we need to check
3389 // adjust_method_entries() for every InstanceKlass, which will also
3390 // adjust the default method vtable indices.
3391 // We also need to adjust any default method entries that are
3392 // not yet in the vtable, because the vtable setup is in progress.
3393 // This must be done after we adjust the default_methods and
3394 // default_vtable_indices for methods already in the vtable.
3395 // If redefining Unsafe, walk all the vtables looking for entries.
3396 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
3397 || _the_class_oop == SystemDictionary::misc_Unsafe_klass()
3398 || ik->is_subtype_of(_the_class_oop))) {
3399 // ik->vtable() creates a wrapper object; rm cleans it up
3400 ResourceMark rm(_thread);
3401
3402 ik->vtable()->adjust_method_entries(the_class, &trace_name_printed);
3403 ik->adjust_default_methods(the_class, &trace_name_printed);
3404 }
3405
3406 // If the current class has an itable and we are either redefining an
3407 // interface or if the current class is a subclass of the_class, then
3408 // we potentially have to fix the itable. If we are redefining an
3409 // interface, then we have to call adjust_method_entries() for
3410 // every InstanceKlass that has an itable since there isn't a
3411 // subclass relationship between an interface and an InstanceKlass.
3412 // If redefining Unsafe, walk all the itables looking for entries.
3413 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
3414 || _the_class_oop == SystemDictionary::misc_Unsafe_klass()
3415 || ik->is_subclass_of(_the_class_oop))) {
3416 // ik->itable() creates a wrapper object; rm cleans it up
3417 ResourceMark rm(_thread);
3418
3419 ik->itable()->adjust_method_entries(the_class, &trace_name_printed);
3420 }
3421
3422 // The constant pools in other classes (other_cp) can refer to
3423 // methods in the_class. We have to update method information in
3424 // other_cp's cache. If other_cp has a previous version, then we
3425 // have to repeat the process for each previous version. The
3426 // constant pool cache holds the Method*s for non-virtual
3427 // methods and for virtual, final methods.
3428 //
3429 // Special case: if the current class is the_class, then new_cp
3430 // has already been attached to the_class and old_cp has already
3431 // been added as a previous version. The new_cp doesn't have any
3432 // cached references to old methods so it doesn't need to be
3433 // updated. We can simply start with the previous version(s) in
3434 // that case.
3435 constantPoolHandle other_cp;
3436 ConstantPoolCache* cp_cache;
3437
3438 if (ik != _the_class_oop) {
3439 // this klass' constant pool cache may need adjustment
3440 other_cp = constantPoolHandle(ik->constants());
3441 cp_cache = other_cp->cache();
3442 if (cp_cache != NULL) {
3443 cp_cache->adjust_method_entries(the_class, &trace_name_printed);
3444 }
3445 }
3446
3447 // the previous versions' constant pool caches may need adjustment
3448 for (InstanceKlass* pv_node = ik->previous_versions();
3449 pv_node != NULL;
3450 pv_node = pv_node->previous_versions()) {
3451 cp_cache = pv_node->constants()->cache();
3452 if (cp_cache != NULL) {
3453 cp_cache->adjust_method_entries(pv_node, &trace_name_printed);
3454 }
3455 }
3456 }
3457 }
3458
3459 void VM_RedefineClasses::update_jmethod_ids() {
3460 for (int j = 0; j < _matching_methods_length; ++j) {
3461 Method* old_method = _matching_old_methods[j];
3462 jmethodID jmid = old_method->find_jmethod_id_or_null();
3463 if (jmid != NULL) {
3464 // There is a jmethodID, change it to point to the new method
3465 methodHandle new_method_h(_matching_new_methods[j]);
3466 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
3467 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
3468 "should be replaced");
3469 }
3470 }
3471 }
3472
3473 int VM_RedefineClasses::check_methods_and_mark_as_obsolete() {
3474 int emcp_method_count = 0;
3475 int obsolete_count = 0;
3476 int old_index = 0;
3477 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
3478 Method* old_method = _matching_old_methods[j];
3479 Method* new_method = _matching_new_methods[j];
3480 Method* old_array_method;
3481
3482 // Maintain an old_index into the _old_methods array by skipping
3483 // deleted methods
3484 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
3485 ++old_index;
3486 }
3487
3488 if (MethodComparator::methods_EMCP(old_method, new_method)) {
3489 // The EMCP definition from JSR-163 requires the bytecodes to be
3490 // the same with the exception of constant pool indices which may
3491 // differ. However, the constants referred to by those indices
3492 // must be the same.
3493 //
3494 // We use methods_EMCP() for comparison since constant pool
3495 // merging can remove duplicate constant pool entries that were
3496 // present in the old method and removed from the rewritten new
3497 // method. A faster binary comparison function would consider the
3498 // old and new methods to be different when they are actually
3499 // EMCP.
3500 //
3501 // The old and new methods are EMCP and you would think that we
3502 // could get rid of one of them here and now and save some space.
3503 // However, the concept of EMCP only considers the bytecodes and
3504 // the constant pool entries in the comparison. Other things,
3505 // e.g., the line number table (LNT) or the local variable table
3506 // (LVT) don't count in the comparison. So the new (and EMCP)
3507 // method can have a new LNT that we need so we can't just
3508 // overwrite the new method with the old method.
3509 //
3510 // When this routine is called, we have already attached the new
3511 // methods to the_class so the old methods are effectively
3512 // overwritten. However, if an old method is still executing,
3513 // then the old method cannot be collected until sometime after
3514 // the old method call has returned. So the overwriting of old
3515 // methods by new methods will save us space except for those
3516 // (hopefully few) old methods that are still executing.
3517 //
3518 // A method refers to a ConstMethod* and this presents another
3519 // possible avenue to space savings. The ConstMethod* in the
3520 // new method contains possibly new attributes (LNT, LVT, etc).
3521 // At first glance, it seems possible to save space by replacing
3522 // the ConstMethod* in the old method with the ConstMethod*
3523 // from the new method. The old and new methods would share the
3524 // same ConstMethod* and we would save the space occupied by
3525 // the old ConstMethod*. However, the ConstMethod* contains
3526 // a back reference to the containing method. Sharing the
3527 // ConstMethod* between two methods could lead to confusion in
3528 // the code that uses the back reference. This would lead to
3529 // brittle code that could be broken in non-obvious ways now or
3530 // in the future.
3531 //
3532 // Another possibility is to copy the ConstMethod* from the new
3533 // method to the old method and then overwrite the new method with
3534 // the old method. Since the ConstMethod* contains the bytecodes
3535 // for the method embedded in the oop, this option would change
3536 // the bytecodes out from under any threads executing the old
3537 // method and make the thread's bcp invalid. Since EMCP requires
3538 // that the bytecodes be the same modulo constant pool indices, it
3539 // is straight forward to compute the correct new bcp in the new
3540 // ConstMethod* from the old bcp in the old ConstMethod*. The
3541 // time consuming part would be searching all the frames in all
3542 // of the threads to find all of the calls to the old method.
3543 //
3544 // It looks like we will have to live with the limited savings
3545 // that we get from effectively overwriting the old methods
3546 // when the new methods are attached to the_class.
3547
3548 // Count number of methods that are EMCP. The method will be marked
3549 // old but not obsolete if it is EMCP.
3550 emcp_method_count++;
3551
3552 // An EMCP method is _not_ obsolete. An obsolete method has a
3553 // different jmethodID than the current method. An EMCP method
3554 // has the same jmethodID as the current method. Having the
3555 // same jmethodID for all EMCP versions of a method allows for
3556 // a consistent view of the EMCP methods regardless of which
3557 // EMCP method you happen to have in hand. For example, a
3558 // breakpoint set in one EMCP method will work for all EMCP
3559 // versions of the method including the current one.
3560 } else {
3561 // mark obsolete methods as such
3562 old_method->set_is_obsolete();
3563 obsolete_count++;
3564
3565 // obsolete methods need a unique idnum so they become new entries in
3566 // the jmethodID cache in InstanceKlass
3567 assert(old_method->method_idnum() == new_method->method_idnum(), "must match");
3568 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
3569 if (num != ConstMethod::UNSET_IDNUM) {
3570 old_method->set_method_idnum(num);
3571 }
3572
3573 // With tracing we try not to "yack" too much. The position of
3574 // this trace assumes there are fewer obsolete methods than
3575 // EMCP methods.
3576 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
3577 old_method->name()->as_C_string(),
3578 old_method->signature()->as_C_string()));
3579 }
3580 old_method->set_is_old();
3581 }
3582 for (int i = 0; i < _deleted_methods_length; ++i) {
3583 Method* old_method = _deleted_methods[i];
3584
3585 assert(!old_method->has_vtable_index(),
3586 "cannot delete methods with vtable entries");;
3587
3588 // Mark all deleted methods as old, obsolete and deleted
3589 old_method->set_is_deleted();
3590 old_method->set_is_old();
3591 old_method->set_is_obsolete();
3592 ++obsolete_count;
3593 // With tracing we try not to "yack" too much. The position of
3594 // this trace assumes there are fewer obsolete methods than
3595 // EMCP methods.
3596 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
3597 old_method->name()->as_C_string(),
3598 old_method->signature()->as_C_string()));
3599 }
3600 assert((emcp_method_count + obsolete_count) == _old_methods->length(),
3601 "sanity check");
3602 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count,
3603 obsolete_count));
3604 return emcp_method_count;
3605 }
3606
3607 // This internal class transfers the native function registration from old methods
3608 // to new methods. It is designed to handle both the simple case of unchanged
3609 // native methods and the complex cases of native method prefixes being added and/or
3610 // removed.
3611 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
3612 //
3613 // This class is used after the new methods have been installed in "the_class".
3614 //
3615 // So, for example, the following must be handled. Where 'm' is a method and
3616 // a number followed by an underscore is a prefix.
3617 //
3618 // Old Name New Name
3619 // Simple transfer to new method m -> m
3620 // Add prefix m -> 1_m
3621 // Remove prefix 1_m -> m
3622 // Simultaneous add of prefixes m -> 3_2_1_m
3623 // Simultaneous removal of prefixes 3_2_1_m -> m
3624 // Simultaneous add and remove 1_m -> 2_m
3625 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3626 //
3627 class TransferNativeFunctionRegistration {
3628 private:
3629 instanceKlassHandle the_class;
3630 int prefix_count;
3631 char** prefixes;
3632
3633 // Recursively search the binary tree of possibly prefixed method names.
3634 // Iteration could be used if all agents were well behaved. Full tree walk is
3635 // more resilent to agents not cleaning up intermediate methods.
3636 // Branch at each depth in the binary tree is:
3637 // (1) without the prefix.
3638 // (2) with the prefix.
3639 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3640 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3641 Symbol* signature) {
3642 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3643 if (name_symbol != NULL) {
3644 Method* method = the_class()->lookup_method(name_symbol, signature);
3645 if (method != NULL) {
3646 // Even if prefixed, intermediate methods must exist.
3647 if (method->is_native()) {
3648 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3649 return method;
3650 }
3651 if (depth < prefix_count) {
3652 // Try applying further prefixes (other than this one).
3653 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3654 if (method != NULL) {
3655 return method; // found
3656 }
3657
3658 // Try adding this prefix to the method name and see if it matches
3659 // another method name.
3660 char* prefix = prefixes[depth];
3661 size_t prefix_len = strlen(prefix);
3662 size_t trial_len = name_len + prefix_len;
3663 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3664 strcpy(trial_name_str, prefix);
3665 strcat(trial_name_str, name_str);
3666 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3667 signature);
3668 if (method != NULL) {
3669 // If found along this branch, it was prefixed, mark as such
3670 method->set_is_prefixed_native();
3671 return method; // found
3672 }
3673 }
3674 }
3675 }
3676 return NULL; // This whole branch bore nothing
3677 }
3678
3679 // Return the method name with old prefixes stripped away.
3680 char* method_name_without_prefixes(Method* method) {
3681 Symbol* name = method->name();
3682 char* name_str = name->as_utf8();
3683
3684 // Old prefixing may be defunct, strip prefixes, if any.
3685 for (int i = prefix_count-1; i >= 0; i--) {
3686 char* prefix = prefixes[i];
3687 size_t prefix_len = strlen(prefix);
3688 if (strncmp(prefix, name_str, prefix_len) == 0) {
3689 name_str += prefix_len;
3690 }
3691 }
3692 return name_str;
3693 }
3694
3695 // Strip any prefixes off the old native method, then try to find a
3696 // (possibly prefixed) new native that matches it.
3697 Method* strip_and_search_for_new_native(Method* method) {
3698 ResourceMark rm;
3699 char* name_str = method_name_without_prefixes(method);
3700 return search_prefix_name_space(0, name_str, strlen(name_str),
3701 method->signature());
3702 }
3703
3704 public:
3705
3706 // Construct a native method transfer processor for this class.
3707 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3708 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3709
3710 the_class = _the_class;
3711 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3712 }
3713
3714 // Attempt to transfer any of the old or deleted methods that are native
3715 void transfer_registrations(Method** old_methods, int methods_length) {
3716 for (int j = 0; j < methods_length; j++) {
3717 Method* old_method = old_methods[j];
3718
3719 if (old_method->is_native() && old_method->has_native_function()) {
3720 Method* new_method = strip_and_search_for_new_native(old_method);
3721 if (new_method != NULL) {
3722 // Actually set the native function in the new method.
3723 // Redefine does not send events (except CFLH), certainly not this
3724 // behind the scenes re-registration.
3725 new_method->set_native_function(old_method->native_function(),
3726 !Method::native_bind_event_is_interesting);
3727 }
3728 }
3729 }
3730 }
3731 };
3732
3733 // Don't lose the association between a native method and its JNI function.
3734 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3735 TransferNativeFunctionRegistration transfer(the_class);
3736 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3737 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3738 }
3739
3740 // Deoptimize all compiled code that depends on this class.
3741 //
3742 // If the can_redefine_classes capability is obtained in the onload
3743 // phase then the compiler has recorded all dependencies from startup.
3744 // In that case we need only deoptimize and throw away all compiled code
3745 // that depends on the class.
3746 //
3747 // If can_redefine_classes is obtained sometime after the onload
3748 // phase then the dependency information may be incomplete. In that case
3749 // the first call to RedefineClasses causes all compiled code to be
3750 // thrown away. As can_redefine_classes has been obtained then
3751 // all future compilations will record dependencies so second and
3752 // subsequent calls to RedefineClasses need only throw away code
3753 // that depends on the class.
3754 //
3755 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3756 assert_locked_or_safepoint(Compile_lock);
3757
3758 // All dependencies have been recorded from startup or this is a second or
3759 // subsequent use of RedefineClasses
3760 if (JvmtiExport::all_dependencies_are_recorded()) {
3761 Universe::flush_evol_dependents_on(k_h);
3762 } else {
3763 CodeCache::mark_all_nmethods_for_deoptimization();
3764
3765 ResourceMark rm(THREAD);
3766 DeoptimizationMarker dm;
3767
3768 // Deoptimize all activations depending on marked nmethods
3769 Deoptimization::deoptimize_dependents();
3770
3771 // Make the dependent methods not entrant
3772 CodeCache::make_marked_nmethods_not_entrant();
3773
3774 // From now on we know that the dependency information is complete
3775 JvmtiExport::set_all_dependencies_are_recorded(true);
3776 }
3777 }
3778
3779 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3780 Method* old_method;
3781 Method* new_method;
3782
3783 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3784 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3785 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3786 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3787
3788 _matching_methods_length = 0;
3789 _deleted_methods_length = 0;
3790 _added_methods_length = 0;
3791
3792 int nj = 0;
3793 int oj = 0;
3794 while (true) {
3795 if (oj >= _old_methods->length()) {
3796 if (nj >= _new_methods->length()) {
3797 break; // we've looked at everything, done
3798 }
3799 // New method at the end
3800 new_method = _new_methods->at(nj);
3801 _added_methods[_added_methods_length++] = new_method;
3802 ++nj;
3803 } else if (nj >= _new_methods->length()) {
3804 // Old method, at the end, is deleted
3805 old_method = _old_methods->at(oj);
3806 _deleted_methods[_deleted_methods_length++] = old_method;
3807 ++oj;
3808 } else {
3809 old_method = _old_methods->at(oj);
3810 new_method = _new_methods->at(nj);
3811 if (old_method->name() == new_method->name()) {
3812 if (old_method->signature() == new_method->signature()) {
3813 _matching_old_methods[_matching_methods_length ] = old_method;
3814 _matching_new_methods[_matching_methods_length++] = new_method;
3815 ++nj;
3816 ++oj;
3817 } else {
3818 // added overloaded have already been moved to the end,
3819 // so this is a deleted overloaded method
3820 _deleted_methods[_deleted_methods_length++] = old_method;
3821 ++oj;
3822 }
3823 } else { // names don't match
3824 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3825 // new method
3826 _added_methods[_added_methods_length++] = new_method;
3827 ++nj;
3828 } else {
3829 // deleted method
3830 _deleted_methods[_deleted_methods_length++] = old_method;
3831 ++oj;
3832 }
3833 }
3834 }
3835 }
3836 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3837 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3838 }
3839
3840
3841 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3842 instanceKlassHandle scratch_class) {
3843 // Swap annotation fields values
3844 Annotations* old_annotations = the_class->annotations();
3845 the_class->set_annotations(scratch_class->annotations());
3846 scratch_class->set_annotations(old_annotations);
3847 }
3848
3849
3850 // Install the redefinition of a class:
3851 // - house keeping (flushing breakpoints and caches, deoptimizing
3852 // dependent compiled code)
3853 // - replacing parts in the_class with parts from scratch_class
3854 // - adding a weak reference to track the obsolete but interesting
3855 // parts of the_class
3856 // - adjusting constant pool caches and vtables in other classes
3857 // that refer to methods in the_class. These adjustments use the
3858 // ClassLoaderDataGraph::classes_do() facility which only allows
3859 // a helper method to be specified. The interesting parameters
3860 // that we would like to pass to the helper method are saved in
3861 // static global fields in the VM operation.
3862 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3863 Klass* scratch_class_oop, TRAPS) {
3864
3865 HandleMark hm(THREAD); // make sure handles from this call are freed
3866 RC_TIMER_START(_timer_rsc_phase1);
3867
3868 instanceKlassHandle scratch_class(scratch_class_oop);
3869
3870 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3871 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3872 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3873
3874 // Remove all breakpoints in methods of this class
3875 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3876 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3877
3878 // Deoptimize all compiled code that depends on this class
3879 flush_dependent_code(the_class, THREAD);
3880
3881 _old_methods = the_class->methods();
3882 _new_methods = scratch_class->methods();
3883 _the_class_oop = the_class_oop;
3884 compute_added_deleted_matching_methods();
3885 update_jmethod_ids();
3886
3887 // Attach new constant pool to the original klass. The original
3888 // klass still refers to the old constant pool (for now).
3889 scratch_class->constants()->set_pool_holder(the_class());
3890
3891 #if 0
3892 // In theory, with constant pool merging in place we should be able
3893 // to save space by using the new, merged constant pool in place of
3894 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3895 // the klass version we are replacing now and any constant pool(s) in
3896 // previous versions of klass. Nice theory, doesn't work in practice.
3897 // When this code is enabled, even simple programs throw NullPointer
3898 // exceptions. I'm guessing that this is caused by some constant pool
3899 // cache difference between the new, merged constant pool and the
3900 // constant pool that was just being used by the klass. I'm keeping
3901 // this code around to archive the idea, but the code has to remain
3902 // disabled for now.
3903
3904 // Attach each old method to the new constant pool. This can be
3905 // done here since we are past the bytecode verification and
3906 // constant pool optimization phases.
3907 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3908 Method* method = _old_methods->at(i);
3909 method->set_constants(scratch_class->constants());
3910 }
3911
3912 {
3913 // walk all previous versions of the klass
3914 InstanceKlass *ik = (InstanceKlass *)the_class();
3915 PreviousVersionWalker pvw(ik);
3916 instanceKlassHandle ikh;
3917 do {
3918 ikh = pvw.next_previous_version();
3919 if (!ikh.is_null()) {
3920 ik = ikh();
3921
3922 // attach previous version of klass to the new constant pool
3923 ik->set_constants(scratch_class->constants());
3924
3925 // Attach each method in the previous version of klass to the
3926 // new constant pool
3927 Array<Method*>* prev_methods = ik->methods();
3928 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3929 Method* method = prev_methods->at(i);
3930 method->set_constants(scratch_class->constants());
3931 }
3932 }
3933 } while (!ikh.is_null());
3934 }
3935 #endif
3936
3937 // Replace methods and constantpool
3938 the_class->set_methods(_new_methods);
3939 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3940 // and to be able to undo operation easily.
3941
3942 Array<int>* old_ordering = the_class->method_ordering();
3943 the_class->set_method_ordering(scratch_class->method_ordering());
3944 scratch_class->set_method_ordering(old_ordering);
3945
3946 ConstantPool* old_constants = the_class->constants();
3947 the_class->set_constants(scratch_class->constants());
3948 scratch_class->set_constants(old_constants); // See the previous comment.
3949 #if 0
3950 // We are swapping the guts of "the new class" with the guts of "the
3951 // class". Since the old constant pool has just been attached to "the
3952 // new class", it seems logical to set the pool holder in the old
3953 // constant pool also. However, doing this will change the observable
3954 // class hierarchy for any old methods that are still executing. A
3955 // method can query the identity of its "holder" and this query uses
3956 // the method's constant pool link to find the holder. The change in
3957 // holding class from "the class" to "the new class" can confuse
3958 // things.
3959 //
3960 // Setting the old constant pool's holder will also cause
3961 // verification done during vtable initialization below to fail.
3962 // During vtable initialization, the vtable's class is verified to be
3963 // a subtype of the method's holder. The vtable's class is "the
3964 // class" and the method's holder is gotten from the constant pool
3965 // link in the method itself. For "the class"'s directly implemented
3966 // methods, the method holder is "the class" itself (as gotten from
3967 // the new constant pool). The check works fine in this case. The
3968 // check also works fine for methods inherited from super classes.
3969 //
3970 // Miranda methods are a little more complicated. A miranda method is
3971 // provided by an interface when the class implementing the interface
3972 // does not provide its own method. These interfaces are implemented
3973 // internally as an InstanceKlass. These special instanceKlasses
3974 // share the constant pool of the class that "implements" the
3975 // interface. By sharing the constant pool, the method holder of a
3976 // miranda method is the class that "implements" the interface. In a
3977 // non-redefine situation, the subtype check works fine. However, if
3978 // the old constant pool's pool holder is modified, then the check
3979 // fails because there is no class hierarchy relationship between the
3980 // vtable's class and "the new class".
3981
3982 old_constants->set_pool_holder(scratch_class());
3983 #endif
3984
3985 // track number of methods that are EMCP for add_previous_version() call below
3986 int emcp_method_count = check_methods_and_mark_as_obsolete();
3987 transfer_old_native_function_registrations(the_class);
3988
3989 // The class file bytes from before any retransformable agents mucked
3990 // with them was cached on the scratch class, move to the_class.
3991 // Note: we still want to do this if nothing needed caching since it
3992 // should get cleared in the_class too.
3993 if (the_class->get_cached_class_file() == 0) {
3994 // the_class doesn't have a cache yet so copy it
3995 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3996 }
3997 else if (scratch_class->get_cached_class_file() !=
3998 the_class->get_cached_class_file()) {
3999 // The same class can be present twice in the scratch classes list or there
4000 // are multiple concurrent RetransformClasses calls on different threads.
4001 // In such cases we have to deallocate scratch_class cached_class_file.
4002 os::free(scratch_class->get_cached_class_file());
4003 }
4004
4005 // NULL out in scratch class to not delete twice. The class to be redefined
4006 // always owns these bytes.
4007 scratch_class->set_cached_class_file(NULL);
4008
4009 // Replace inner_classes
4010 Array<u2>* old_inner_classes = the_class->inner_classes();
4011 the_class->set_inner_classes(scratch_class->inner_classes());
4012 scratch_class->set_inner_classes(old_inner_classes);
4013
4014 // Initialize the vtable and interface table after
4015 // methods have been rewritten
4016 {
4017 ResourceMark rm(THREAD);
4018 // no exception should happen here since we explicitly
4019 // do not check loader constraints.
4020 // compare_and_normalize_class_versions has already checked:
4021 // - classloaders unchanged, signatures unchanged
4022 // - all instanceKlasses for redefined classes reused & contents updated
4023 the_class->vtable()->initialize_vtable(false, THREAD);
4024 the_class->itable()->initialize_itable(false, THREAD);
4025 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
4026 }
4027
4028 // Leave arrays of jmethodIDs and itable index cache unchanged
4029
4030 // Copy the "source file name" attribute from new class version
4031 the_class->set_source_file_name_index(
4032 scratch_class->source_file_name_index());
4033
4034 // Copy the "source debug extension" attribute from new class version
4035 the_class->set_source_debug_extension(
4036 scratch_class->source_debug_extension(),
4037 scratch_class->source_debug_extension() == NULL ? 0 :
4038 (int)strlen(scratch_class->source_debug_extension()));
4039
4040 // Use of javac -g could be different in the old and the new
4041 if (scratch_class->access_flags().has_localvariable_table() !=
4042 the_class->access_flags().has_localvariable_table()) {
4043
4044 AccessFlags flags = the_class->access_flags();
4045 if (scratch_class->access_flags().has_localvariable_table()) {
4046 flags.set_has_localvariable_table();
4047 } else {
4048 flags.clear_has_localvariable_table();
4049 }
4050 the_class->set_access_flags(flags);
4051 }
4052
4053 swap_annotations(the_class, scratch_class);
4054
4055 // Replace minor version number of class file
4056 u2 old_minor_version = the_class->minor_version();
4057 the_class->set_minor_version(scratch_class->minor_version());
4058 scratch_class->set_minor_version(old_minor_version);
4059
4060 // Replace major version number of class file
4061 u2 old_major_version = the_class->major_version();
4062 the_class->set_major_version(scratch_class->major_version());
4063 scratch_class->set_major_version(old_major_version);
4064
4065 // Replace CP indexes for class and name+type of enclosing method
4066 u2 old_class_idx = the_class->enclosing_method_class_index();
4067 u2 old_method_idx = the_class->enclosing_method_method_index();
4068 the_class->set_enclosing_method_indices(
4069 scratch_class->enclosing_method_class_index(),
4070 scratch_class->enclosing_method_method_index());
4071 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
4072
4073 the_class->set_has_been_redefined();
4074
4075 // keep track of previous versions of this class
4076 the_class->add_previous_version(scratch_class, emcp_method_count);
4077
4078 RC_TIMER_STOP(_timer_rsc_phase1);
4079 RC_TIMER_START(_timer_rsc_phase2);
4080
4081 // Adjust constantpool caches and vtables for all classes
4082 // that reference methods of the evolved class.
4083 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
4084 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
4085
4086 // JSR-292 support
4087 MemberNameTable* mnt = the_class->member_names();
4088 if (mnt != NULL) {
4089 bool trace_name_printed = false;
4090 mnt->adjust_method_entries(the_class(), &trace_name_printed);
4091 }
4092
4093 if (the_class->oop_map_cache() != NULL) {
4094 // Flush references to any obsolete methods from the oop map cache
4095 // so that obsolete methods are not pinned.
4096 the_class->oop_map_cache()->flush_obsolete_entries();
4097 }
4098
4099 // increment the classRedefinedCount field in the_class and in any
4100 // direct and indirect subclasses of the_class
4101 increment_class_counter((InstanceKlass *)the_class(), THREAD);
4102
4103 // RC_TRACE macro has an embedded ResourceMark
4104 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
4105 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
4106 the_class->external_name(),
4107 java_lang_Class::classRedefinedCount(the_class_mirror),
4108 os::available_memory() >> 10));
4109
4110 {
4111 ResourceMark rm(THREAD);
4112 Events::log_redefinition(THREAD, "redefined class name=%s, count=%d",
4113 the_class->external_name(),
4114 java_lang_Class::classRedefinedCount(the_class_mirror));
4115
4116 }
4117 RC_TIMER_STOP(_timer_rsc_phase2);
4118 } // end redefine_single_class()
4119
4120
4121 // Increment the classRedefinedCount field in the specific InstanceKlass
4122 // and in all direct and indirect subclasses.
4123 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
4124 oop class_mirror = ik->java_mirror();
4125 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
4126 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
4127 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
4128
4129 if (class_oop != _the_class_oop) {
4130 // _the_class_oop count is printed at end of redefine_single_class()
4131 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
4132 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
4133 }
4134
4135 for (Klass *subk = ik->subklass(); subk != NULL;
4136 subk = subk->next_sibling()) {
4137 if (subk->oop_is_instance()) {
4138 // Only update instanceKlasses
4139 InstanceKlass *subik = (InstanceKlass*)subk;
4140 // recursively do subclasses of the current subclass
4141 increment_class_counter(subik, THREAD);
4142 }
4143 }
4144 }
4145
4146 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
4147 bool no_old_methods = true; // be optimistic
4148
4149 // Both array and instance classes have vtables.
4150 // a vtable should never contain old or obsolete methods
4151 ResourceMark rm(_thread);
4152 if (k->vtable_length() > 0 &&
4153 !k->vtable()->check_no_old_or_obsolete_entries()) {
4154 if (RC_TRACE_ENABLED(0x00004000)) {
4155 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4156 ("klassVtable::check_no_old_or_obsolete_entries failure"
4157 " -- OLD or OBSOLETE method found -- class: %s",
4158 k->signature_name()));
4159 k->vtable()->dump_vtable();
4160 }
4161 no_old_methods = false;
4162 }
4163
4164 if (k->oop_is_instance()) {
4165 HandleMark hm(_thread);
4166 InstanceKlass *ik = InstanceKlass::cast(k);
4167
4168 // an itable should never contain old or obsolete methods
4169 if (ik->itable_length() > 0 &&
4170 !ik->itable()->check_no_old_or_obsolete_entries()) {
4171 if (RC_TRACE_ENABLED(0x00004000)) {
4172 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4173 ("klassItable::check_no_old_or_obsolete_entries failure"
4174 " -- OLD or OBSOLETE method found -- class: %s",
4175 ik->signature_name()));
4176 ik->itable()->dump_itable();
4177 }
4178 no_old_methods = false;
4179 }
4180
4181 // the constant pool cache should never contain non-deleted old or obsolete methods
4182 if (ik->constants() != NULL &&
4183 ik->constants()->cache() != NULL &&
4184 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
4185 if (RC_TRACE_ENABLED(0x00004000)) {
4186 RC_TRACE_WITH_THREAD(0x00004000, _thread,
4187 ("cp-cache::check_no_old_or_obsolete_entries failure"
4188 " -- OLD or OBSOLETE method found -- class: %s",
4189 ik->signature_name()));
4190 ik->constants()->cache()->dump_cache();
4191 }
4192 no_old_methods = false;
4193 }
4194 }
4195
4196 // print and fail guarantee if old methods are found.
4197 if (!no_old_methods) {
4198 if (RC_TRACE_ENABLED(0x00004000)) {
4199 dump_methods();
4200 } else {
4201 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
4202 "to see more info about the following guarantee() failure.");
4203 }
4204 guarantee(false, "OLD and/or OBSOLETE method(s) found");
4205 }
4206 }
4207
4208
4209 void VM_RedefineClasses::dump_methods() {
4210 int j;
4211 RC_TRACE(0x00004000, ("_old_methods --"));
4212 for (j = 0; j < _old_methods->length(); ++j) {
4213 Method* m = _old_methods->at(j);
4214 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4215 m->access_flags().print_on(tty);
4216 tty->print(" -- ");
4217 m->print_name(tty);
4218 tty->cr();
4219 }
4220 RC_TRACE(0x00004000, ("_new_methods --"));
4221 for (j = 0; j < _new_methods->length(); ++j) {
4222 Method* m = _new_methods->at(j);
4223 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4224 m->access_flags().print_on(tty);
4225 tty->print(" -- ");
4226 m->print_name(tty);
4227 tty->cr();
4228 }
4229 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
4230 for (j = 0; j < _matching_methods_length; ++j) {
4231 Method* m = _matching_old_methods[j];
4232 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4233 m->access_flags().print_on(tty);
4234 tty->print(" -- ");
4235 m->print_name(tty);
4236 tty->cr();
4237 m = _matching_new_methods[j];
4238 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
4239 m->access_flags().print_on(tty);
4240 tty->cr();
4241 }
4242 RC_TRACE(0x00004000, ("_deleted_methods --"));
4243 for (j = 0; j < _deleted_methods_length; ++j) {
4244 Method* m = _deleted_methods[j];
4245 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4246 m->access_flags().print_on(tty);
4247 tty->print(" -- ");
4248 m->print_name(tty);
4249 tty->cr();
4250 }
4251 RC_TRACE(0x00004000, ("_added_methods --"));
4252 for (j = 0; j < _added_methods_length; ++j) {
4253 Method* m = _added_methods[j];
4254 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
4255 m->access_flags().print_on(tty);
4256 tty->print(" -- ");
4257 m->print_name(tty);
4258 tty->cr();
4259 }
4260 }
4261
4262 void VM_RedefineClasses::print_on_error(outputStream* st) const {
4263 VM_Operation::print_on_error(st);
4264 if (_the_class_oop != NULL) {
4265 ResourceMark rm;
4266 st->print_cr(", redefining class %s", _the_class_oop->external_name());
4267 }
4268 }