Wed, 27 Apr 2016 01:25:04 +0800
Initial load
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17
1 /*
2 * Copyright (c) 2003, 2014, 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 */
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"
46 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
48 Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
49 Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
50 Method** VM_RedefineClasses::_matching_old_methods = NULL;
51 Method** VM_RedefineClasses::_matching_new_methods = NULL;
52 Method** VM_RedefineClasses::_deleted_methods = NULL;
53 Method** VM_RedefineClasses::_added_methods = NULL;
54 int VM_RedefineClasses::_matching_methods_length = 0;
55 int VM_RedefineClasses::_deleted_methods_length = 0;
56 int VM_RedefineClasses::_added_methods_length = 0;
57 Klass* VM_RedefineClasses::_the_class_oop = NULL;
60 VM_RedefineClasses::VM_RedefineClasses(jint class_count,
61 const jvmtiClassDefinition *class_defs,
62 JvmtiClassLoadKind class_load_kind) {
63 _class_count = class_count;
64 _class_defs = class_defs;
65 _class_load_kind = class_load_kind;
66 _res = JVMTI_ERROR_NONE;
67 }
69 bool VM_RedefineClasses::doit_prologue() {
70 if (_class_count == 0) {
71 _res = JVMTI_ERROR_NONE;
72 return false;
73 }
74 if (_class_defs == NULL) {
75 _res = JVMTI_ERROR_NULL_POINTER;
76 return false;
77 }
78 for (int i = 0; i < _class_count; i++) {
79 if (_class_defs[i].klass == NULL) {
80 _res = JVMTI_ERROR_INVALID_CLASS;
81 return false;
82 }
83 if (_class_defs[i].class_byte_count == 0) {
84 _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
85 return false;
86 }
87 if (_class_defs[i].class_bytes == NULL) {
88 _res = JVMTI_ERROR_NULL_POINTER;
89 return false;
90 }
91 }
93 // Start timer after all the sanity checks; not quite accurate, but
94 // better than adding a bunch of stop() calls.
95 RC_TIMER_START(_timer_vm_op_prologue);
97 // We first load new class versions in the prologue, because somewhere down the
98 // call chain it is required that the current thread is a Java thread.
99 _res = load_new_class_versions(Thread::current());
100 if (_res != JVMTI_ERROR_NONE) {
101 // free any successfully created classes, since none are redefined
102 for (int i = 0; i < _class_count; i++) {
103 if (_scratch_classes[i] != NULL) {
104 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
105 // Free the memory for this class at class unloading time. Not before
106 // because CMS might think this is still live.
107 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
108 }
109 }
110 // Free os::malloc allocated memory in load_new_class_version.
111 os::free(_scratch_classes);
112 RC_TIMER_STOP(_timer_vm_op_prologue);
113 return false;
114 }
116 RC_TIMER_STOP(_timer_vm_op_prologue);
117 return true;
118 }
120 void VM_RedefineClasses::doit() {
121 Thread *thread = Thread::current();
123 if (UseSharedSpaces) {
124 // Sharing is enabled so we remap the shared readonly space to
125 // shared readwrite, private just in case we need to redefine
126 // a shared class. We do the remap during the doit() phase of
127 // the safepoint to be safer.
128 if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
129 RC_TRACE_WITH_THREAD(0x00000001, thread,
130 ("failed to remap shared readonly space to readwrite, private"));
131 _res = JVMTI_ERROR_INTERNAL;
132 return;
133 }
134 }
136 // Mark methods seen on stack and everywhere else so old methods are not
137 // cleaned up if they're on the stack.
138 MetadataOnStackMark md_on_stack;
139 HandleMark hm(thread); // make sure any handles created are deleted
140 // before the stack walk again.
142 for (int i = 0; i < _class_count; i++) {
143 redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
144 ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
145 // Free the memory for this class at class unloading time. Not before
146 // because CMS might think this is still live.
147 cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
148 _scratch_classes[i] = NULL;
149 }
151 // Disable any dependent concurrent compilations
152 SystemDictionary::notice_modification();
154 // Set flag indicating that some invariants are no longer true.
155 // See jvmtiExport.hpp for detailed explanation.
156 JvmtiExport::set_has_redefined_a_class();
158 // check_class() is optionally called for product bits, but is
159 // always called for non-product bits.
160 #ifdef PRODUCT
161 if (RC_TRACE_ENABLED(0x00004000)) {
162 #endif
163 RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
164 CheckClass check_class(thread);
165 ClassLoaderDataGraph::classes_do(&check_class);
166 #ifdef PRODUCT
167 }
168 #endif
169 }
171 void VM_RedefineClasses::doit_epilogue() {
172 // Free os::malloc allocated memory.
173 os::free(_scratch_classes);
175 if (RC_TRACE_ENABLED(0x00000004)) {
176 // Used to have separate timers for "doit" and "all", but the timer
177 // overhead skewed the measurements.
178 jlong doit_time = _timer_rsc_phase1.milliseconds() +
179 _timer_rsc_phase2.milliseconds();
180 jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
182 RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
183 " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
184 _timer_vm_op_prologue.milliseconds(), doit_time));
185 RC_TRACE(0x00000004,
186 ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
187 _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
188 }
189 }
191 bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
192 // classes for primitives cannot be redefined
193 if (java_lang_Class::is_primitive(klass_mirror)) {
194 return false;
195 }
196 Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
197 // classes for arrays cannot be redefined
198 if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
199 return false;
200 }
201 return true;
202 }
204 // Append the current entry at scratch_i in scratch_cp to *merge_cp_p
205 // where the end of *merge_cp_p is specified by *merge_cp_length_p. For
206 // direct CP entries, there is just the current entry to append. For
207 // indirect and double-indirect CP entries, there are zero or more
208 // referenced CP entries along with the current entry to append.
209 // Indirect and double-indirect CP entries are handled by recursive
210 // calls to append_entry() as needed. The referenced CP entries are
211 // always appended to *merge_cp_p before the referee CP entry. These
212 // referenced CP entries may already exist in *merge_cp_p in which case
213 // there is nothing extra to append and only the current entry is
214 // appended.
215 void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
216 int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
217 TRAPS) {
219 // append is different depending on entry tag type
220 switch (scratch_cp->tag_at(scratch_i).value()) {
222 // The old verifier is implemented outside the VM. It loads classes,
223 // but does not resolve constant pool entries directly so we never
224 // see Class entries here with the old verifier. Similarly the old
225 // verifier does not like Class entries in the input constant pool.
226 // The split-verifier is implemented in the VM so it can optionally
227 // and directly resolve constant pool entries to load classes. The
228 // split-verifier can accept either Class entries or UnresolvedClass
229 // entries in the input constant pool. We revert the appended copy
230 // back to UnresolvedClass so that either verifier will be happy
231 // with the constant pool entry.
232 case JVM_CONSTANT_Class:
233 {
234 // revert the copy to JVM_CONSTANT_UnresolvedClass
235 (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
236 scratch_cp->klass_name_at(scratch_i));
238 if (scratch_i != *merge_cp_length_p) {
239 // The new entry in *merge_cp_p is at a different index than
240 // the new entry in scratch_cp so we need to map the index values.
241 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
242 }
243 (*merge_cp_length_p)++;
244 } break;
246 // these are direct CP entries so they can be directly appended,
247 // but double and long take two constant pool entries
248 case JVM_CONSTANT_Double: // fall through
249 case JVM_CONSTANT_Long:
250 {
251 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
252 THREAD);
254 if (scratch_i != *merge_cp_length_p) {
255 // The new entry in *merge_cp_p is at a different index than
256 // the new entry in scratch_cp so we need to map the index values.
257 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
258 }
259 (*merge_cp_length_p) += 2;
260 } break;
262 // these are direct CP entries so they can be directly appended
263 case JVM_CONSTANT_Float: // fall through
264 case JVM_CONSTANT_Integer: // fall through
265 case JVM_CONSTANT_Utf8: // fall through
267 // This was an indirect CP entry, but it has been changed into
268 // Symbol*s so this entry can be directly appended.
269 case JVM_CONSTANT_String: // fall through
271 // These were indirect CP entries, but they have been changed into
272 // Symbol*s so these entries can be directly appended.
273 case JVM_CONSTANT_UnresolvedClass: // fall through
274 {
275 ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
276 THREAD);
278 if (scratch_i != *merge_cp_length_p) {
279 // The new entry in *merge_cp_p is at a different index than
280 // the new entry in scratch_cp so we need to map the index values.
281 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
282 }
283 (*merge_cp_length_p)++;
284 } break;
286 // this is an indirect CP entry so it needs special handling
287 case JVM_CONSTANT_NameAndType:
288 {
289 int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
290 int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
291 merge_cp_length_p, THREAD);
293 int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
294 int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
295 merge_cp_p, merge_cp_length_p,
296 THREAD);
298 // If the referenced entries already exist in *merge_cp_p, then
299 // both new_name_ref_i and new_signature_ref_i will both be 0.
300 // In that case, all we are appending is the current entry.
301 if (new_name_ref_i != name_ref_i) {
302 RC_TRACE(0x00080000,
303 ("NameAndType entry@%d name_ref_index change: %d to %d",
304 *merge_cp_length_p, name_ref_i, new_name_ref_i));
305 }
306 if (new_signature_ref_i != signature_ref_i) {
307 RC_TRACE(0x00080000,
308 ("NameAndType entry@%d signature_ref_index change: %d to %d",
309 *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
310 }
312 (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
313 new_name_ref_i, new_signature_ref_i);
314 if (scratch_i != *merge_cp_length_p) {
315 // The new entry in *merge_cp_p is at a different index than
316 // the new entry in scratch_cp so we need to map the index values.
317 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
318 }
319 (*merge_cp_length_p)++;
320 } break;
322 // this is a double-indirect CP entry so it needs special handling
323 case JVM_CONSTANT_Fieldref: // fall through
324 case JVM_CONSTANT_InterfaceMethodref: // fall through
325 case JVM_CONSTANT_Methodref:
326 {
327 int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
328 int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
329 merge_cp_p, merge_cp_length_p, THREAD);
331 int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
332 int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
333 merge_cp_p, merge_cp_length_p, THREAD);
335 const char *entry_name;
336 switch (scratch_cp->tag_at(scratch_i).value()) {
337 case JVM_CONSTANT_Fieldref:
338 entry_name = "Fieldref";
339 (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
340 new_name_and_type_ref_i);
341 break;
342 case JVM_CONSTANT_InterfaceMethodref:
343 entry_name = "IFMethodref";
344 (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
345 new_klass_ref_i, new_name_and_type_ref_i);
346 break;
347 case JVM_CONSTANT_Methodref:
348 entry_name = "Methodref";
349 (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
350 new_name_and_type_ref_i);
351 break;
352 default:
353 guarantee(false, "bad switch");
354 break;
355 }
357 if (klass_ref_i != new_klass_ref_i) {
358 RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
359 entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
360 }
361 if (name_and_type_ref_i != new_name_and_type_ref_i) {
362 RC_TRACE(0x00080000,
363 ("%s entry@%d name_and_type_index changed: %d to %d",
364 entry_name, *merge_cp_length_p, name_and_type_ref_i,
365 new_name_and_type_ref_i));
366 }
368 if (scratch_i != *merge_cp_length_p) {
369 // The new entry in *merge_cp_p is at a different index than
370 // the new entry in scratch_cp so we need to map the index values.
371 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
372 }
373 (*merge_cp_length_p)++;
374 } break;
376 // this is an indirect CP entry so it needs special handling
377 case JVM_CONSTANT_MethodType:
378 {
379 int ref_i = scratch_cp->method_type_index_at(scratch_i);
380 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
381 merge_cp_length_p, THREAD);
382 if (new_ref_i != ref_i) {
383 RC_TRACE(0x00080000,
384 ("MethodType entry@%d ref_index change: %d to %d",
385 *merge_cp_length_p, ref_i, new_ref_i));
386 }
387 (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
388 if (scratch_i != *merge_cp_length_p) {
389 // The new entry in *merge_cp_p is at a different index than
390 // the new entry in scratch_cp so we need to map the index values.
391 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
392 }
393 (*merge_cp_length_p)++;
394 } break;
396 // this is an indirect CP entry so it needs special handling
397 case JVM_CONSTANT_MethodHandle:
398 {
399 int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
400 int ref_i = scratch_cp->method_handle_index_at(scratch_i);
401 int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
402 merge_cp_length_p, THREAD);
403 if (new_ref_i != ref_i) {
404 RC_TRACE(0x00080000,
405 ("MethodHandle entry@%d ref_index change: %d to %d",
406 *merge_cp_length_p, ref_i, new_ref_i));
407 }
408 (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
409 if (scratch_i != *merge_cp_length_p) {
410 // The new entry in *merge_cp_p is at a different index than
411 // the new entry in scratch_cp so we need to map the index values.
412 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
413 }
414 (*merge_cp_length_p)++;
415 } break;
417 // this is an indirect CP entry so it needs special handling
418 case JVM_CONSTANT_InvokeDynamic:
419 {
420 // Index of the bootstrap specifier in the operands array
421 int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
422 int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
423 merge_cp_length_p, THREAD);
424 // The bootstrap method NameAndType_info index
425 int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
426 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
427 merge_cp_length_p, THREAD);
428 if (new_bs_i != old_bs_i) {
429 RC_TRACE(0x00080000,
430 ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
431 *merge_cp_length_p, old_bs_i, new_bs_i));
432 }
433 if (new_ref_i != old_ref_i) {
434 RC_TRACE(0x00080000,
435 ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
436 *merge_cp_length_p, old_ref_i, new_ref_i));
437 }
439 (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
440 if (scratch_i != *merge_cp_length_p) {
441 // The new entry in *merge_cp_p is at a different index than
442 // the new entry in scratch_cp so we need to map the index values.
443 map_index(scratch_cp, scratch_i, *merge_cp_length_p);
444 }
445 (*merge_cp_length_p)++;
446 } break;
448 // At this stage, Class or UnresolvedClass could be here, but not
449 // ClassIndex
450 case JVM_CONSTANT_ClassIndex: // fall through
452 // Invalid is used as the tag for the second constant pool entry
453 // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
454 // not be seen by itself.
455 case JVM_CONSTANT_Invalid: // fall through
457 // At this stage, String could be here, but not StringIndex
458 case JVM_CONSTANT_StringIndex: // fall through
460 // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
461 // here
462 case JVM_CONSTANT_UnresolvedClassInError: // fall through
464 default:
465 {
466 // leave a breadcrumb
467 jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
468 ShouldNotReachHere();
469 } break;
470 } // end switch tag value
471 } // end append_entry()
474 int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
475 int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
477 int new_ref_i = ref_i;
478 bool match = (ref_i < *merge_cp_length_p) &&
479 scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
481 if (!match) {
482 // forward reference in *merge_cp_p or not a direct match
483 int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
484 if (found_i != 0) {
485 guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
486 // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
487 new_ref_i = found_i;
488 map_index(scratch_cp, ref_i, found_i);
489 } else {
490 // no match found so we have to append this entry to *merge_cp_p
491 append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
492 // The above call to append_entry() can only append one entry
493 // so the post call query of *merge_cp_length_p is only for
494 // the sake of consistency.
495 new_ref_i = *merge_cp_length_p - 1;
496 }
497 }
499 return new_ref_i;
500 } // end find_or_append_indirect_entry()
503 // Append a bootstrap specifier into the merge_cp operands that is semantically equal
504 // to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
505 // Recursively append new merge_cp entries referenced by the new bootstrap specifier.
506 void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
507 constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
509 int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
510 int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
511 merge_cp_length_p, THREAD);
512 if (new_ref_i != old_ref_i) {
513 RC_TRACE(0x00080000,
514 ("operands entry@%d bootstrap method ref_index change: %d to %d",
515 _operands_cur_length, old_ref_i, new_ref_i));
516 }
518 Array<u2>* merge_ops = (*merge_cp_p)->operands();
519 int new_bs_i = _operands_cur_length;
520 // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
521 // However, the operand_offset_at(0) was set in the extend_operands() call.
522 int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
523 : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
524 int argc = scratch_cp->operand_argument_count_at(old_bs_i);
526 ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
527 merge_ops->at_put(new_base++, new_ref_i);
528 merge_ops->at_put(new_base++, argc);
530 for (int i = 0; i < argc; i++) {
531 int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
532 int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
533 merge_cp_length_p, THREAD);
534 merge_ops->at_put(new_base++, new_arg_ref_i);
535 if (new_arg_ref_i != old_arg_ref_i) {
536 RC_TRACE(0x00080000,
537 ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
538 _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
539 }
540 }
541 if (old_bs_i != _operands_cur_length) {
542 // The bootstrap specifier in *merge_cp_p is at a different index than
543 // that in scratch_cp so we need to map the index values.
544 map_operand_index(old_bs_i, new_bs_i);
545 }
546 _operands_cur_length++;
547 } // end append_operand()
550 int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
551 int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
553 int new_bs_i = old_bs_i; // bootstrap specifier index
554 bool match = (old_bs_i < _operands_cur_length) &&
555 scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
557 if (!match) {
558 // forward reference in *merge_cp_p or not a direct match
559 int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
560 _operands_cur_length, THREAD);
561 if (found_i != -1) {
562 guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
563 // found a matching operand somewhere else in *merge_cp_p so just need a mapping
564 new_bs_i = found_i;
565 map_operand_index(old_bs_i, found_i);
566 } else {
567 // no match found so we have to append this bootstrap specifier to *merge_cp_p
568 append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
569 new_bs_i = _operands_cur_length - 1;
570 }
571 }
572 return new_bs_i;
573 } // end find_or_append_operand()
576 void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
577 if (merge_cp->operands() == NULL) {
578 return;
579 }
580 // Shrink the merge_cp operands
581 merge_cp->shrink_operands(_operands_cur_length, CHECK);
583 if (RC_TRACE_ENABLED(0x00040000)) {
584 // don't want to loop unless we are tracing
585 int count = 0;
586 for (int i = 1; i < _operands_index_map_p->length(); i++) {
587 int value = _operands_index_map_p->at(i);
588 if (value != -1) {
589 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
590 ("operands_index_map[%d]: old=%d new=%d", count, i, value));
591 count++;
592 }
593 }
594 }
595 // Clean-up
596 _operands_index_map_p = NULL;
597 _operands_cur_length = 0;
598 _operands_index_map_count = 0;
599 } // end finalize_operands_merge()
602 jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
603 instanceKlassHandle the_class,
604 instanceKlassHandle scratch_class) {
605 int i;
607 // Check superclasses, or rather their names, since superclasses themselves can be
608 // requested to replace.
609 // Check for NULL superclass first since this might be java.lang.Object
610 if (the_class->super() != scratch_class->super() &&
611 (the_class->super() == NULL || scratch_class->super() == NULL ||
612 the_class->super()->name() !=
613 scratch_class->super()->name())) {
614 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
615 }
617 // Check if the number, names and order of directly implemented interfaces are the same.
618 // I think in principle we should just check if the sets of names of directly implemented
619 // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
620 // .java file, also changes in .class file) should not matter. However, comparing sets is
621 // technically a bit more difficult, and, more importantly, I am not sure at present that the
622 // order of interfaces does not matter on the implementation level, i.e. that the VM does not
623 // rely on it somewhere.
624 Array<Klass*>* k_interfaces = the_class->local_interfaces();
625 Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
626 int n_intfs = k_interfaces->length();
627 if (n_intfs != k_new_interfaces->length()) {
628 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
629 }
630 for (i = 0; i < n_intfs; i++) {
631 if (k_interfaces->at(i)->name() !=
632 k_new_interfaces->at(i)->name()) {
633 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
634 }
635 }
637 // Check whether class is in the error init state.
638 if (the_class->is_in_error_state()) {
639 // TBD #5057930: special error code is needed in 1.6
640 return JVMTI_ERROR_INVALID_CLASS;
641 }
643 // Check whether class modifiers are the same.
644 jushort old_flags = (jushort) the_class->access_flags().get_flags();
645 jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
646 if (old_flags != new_flags) {
647 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
648 }
650 // Check if the number, names, types and order of fields declared in these classes
651 // are the same.
652 JavaFieldStream old_fs(the_class);
653 JavaFieldStream new_fs(scratch_class);
654 for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
655 // access
656 old_flags = old_fs.access_flags().as_short();
657 new_flags = new_fs.access_flags().as_short();
658 if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
659 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
660 }
661 // offset
662 if (old_fs.offset() != new_fs.offset()) {
663 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
664 }
665 // name and signature
666 Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
667 Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
668 Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
669 Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
670 if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
671 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
672 }
673 }
675 // If both streams aren't done then we have a differing number of
676 // fields.
677 if (!old_fs.done() || !new_fs.done()) {
678 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
679 }
681 // Do a parallel walk through the old and new methods. Detect
682 // cases where they match (exist in both), have been added in
683 // the new methods, or have been deleted (exist only in the
684 // old methods). The class file parser places methods in order
685 // by method name, but does not order overloaded methods by
686 // signature. In order to determine what fate befell the methods,
687 // this code places the overloaded new methods that have matching
688 // old methods in the same order as the old methods and places
689 // new overloaded methods at the end of overloaded methods of
690 // that name. The code for this order normalization is adapted
691 // from the algorithm used in InstanceKlass::find_method().
692 // Since we are swapping out of order entries as we find them,
693 // we only have to search forward through the overloaded methods.
694 // Methods which are added and have the same name as an existing
695 // method (but different signature) will be put at the end of
696 // the methods with that name, and the name mismatch code will
697 // handle them.
698 Array<Method*>* k_old_methods(the_class->methods());
699 Array<Method*>* k_new_methods(scratch_class->methods());
700 int n_old_methods = k_old_methods->length();
701 int n_new_methods = k_new_methods->length();
702 Thread* thread = Thread::current();
704 int ni = 0;
705 int oi = 0;
706 while (true) {
707 Method* k_old_method;
708 Method* k_new_method;
709 enum { matched, added, deleted, undetermined } method_was = undetermined;
711 if (oi >= n_old_methods) {
712 if (ni >= n_new_methods) {
713 break; // we've looked at everything, done
714 }
715 // New method at the end
716 k_new_method = k_new_methods->at(ni);
717 method_was = added;
718 } else if (ni >= n_new_methods) {
719 // Old method, at the end, is deleted
720 k_old_method = k_old_methods->at(oi);
721 method_was = deleted;
722 } else {
723 // There are more methods in both the old and new lists
724 k_old_method = k_old_methods->at(oi);
725 k_new_method = k_new_methods->at(ni);
726 if (k_old_method->name() != k_new_method->name()) {
727 // Methods are sorted by method name, so a mismatch means added
728 // or deleted
729 if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
730 method_was = added;
731 } else {
732 method_was = deleted;
733 }
734 } else if (k_old_method->signature() == k_new_method->signature()) {
735 // Both the name and signature match
736 method_was = matched;
737 } else {
738 // The name matches, but the signature doesn't, which means we have to
739 // search forward through the new overloaded methods.
740 int nj; // outside the loop for post-loop check
741 for (nj = ni + 1; nj < n_new_methods; nj++) {
742 Method* m = k_new_methods->at(nj);
743 if (k_old_method->name() != m->name()) {
744 // reached another method name so no more overloaded methods
745 method_was = deleted;
746 break;
747 }
748 if (k_old_method->signature() == m->signature()) {
749 // found a match so swap the methods
750 k_new_methods->at_put(ni, m);
751 k_new_methods->at_put(nj, k_new_method);
752 k_new_method = m;
753 method_was = matched;
754 break;
755 }
756 }
758 if (nj >= n_new_methods) {
759 // reached the end without a match; so method was deleted
760 method_was = deleted;
761 }
762 }
763 }
765 switch (method_was) {
766 case matched:
767 // methods match, be sure modifiers do too
768 old_flags = (jushort) k_old_method->access_flags().get_flags();
769 new_flags = (jushort) k_new_method->access_flags().get_flags();
770 if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
771 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
772 }
773 {
774 u2 new_num = k_new_method->method_idnum();
775 u2 old_num = k_old_method->method_idnum();
776 if (new_num != old_num) {
777 Method* idnum_owner = scratch_class->method_with_idnum(old_num);
778 if (idnum_owner != NULL) {
779 // There is already a method assigned this idnum -- switch them
780 idnum_owner->set_method_idnum(new_num);
781 }
782 k_new_method->set_method_idnum(old_num);
783 if (thread->has_pending_exception()) {
784 return JVMTI_ERROR_OUT_OF_MEMORY;
785 }
786 }
787 }
788 RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
789 k_new_method->name_and_sig_as_C_string(), ni,
790 k_old_method->name_and_sig_as_C_string(), oi));
791 // advance to next pair of methods
792 ++oi;
793 ++ni;
794 break;
795 case added:
796 // method added, see if it is OK
797 new_flags = (jushort) k_new_method->access_flags().get_flags();
798 if ((new_flags & JVM_ACC_PRIVATE) == 0
799 // hack: private should be treated as final, but alas
800 || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
801 ) {
802 // new methods must be private
803 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
804 }
805 {
806 u2 num = the_class->next_method_idnum();
807 if (num == ConstMethod::UNSET_IDNUM) {
808 // cannot add any more methods
809 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
810 }
811 u2 new_num = k_new_method->method_idnum();
812 Method* idnum_owner = scratch_class->method_with_idnum(num);
813 if (idnum_owner != NULL) {
814 // There is already a method assigned this idnum -- switch them
815 idnum_owner->set_method_idnum(new_num);
816 }
817 k_new_method->set_method_idnum(num);
818 if (thread->has_pending_exception()) {
819 return JVMTI_ERROR_OUT_OF_MEMORY;
820 }
821 }
822 RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
823 k_new_method->name_and_sig_as_C_string(), ni));
824 ++ni; // advance to next new method
825 break;
826 case deleted:
827 // method deleted, see if it is OK
828 old_flags = (jushort) k_old_method->access_flags().get_flags();
829 if ((old_flags & JVM_ACC_PRIVATE) == 0
830 // hack: private should be treated as final, but alas
831 || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
832 ) {
833 // deleted methods must be private
834 return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
835 }
836 RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
837 k_old_method->name_and_sig_as_C_string(), oi));
838 ++oi; // advance to next old method
839 break;
840 default:
841 ShouldNotReachHere();
842 }
843 }
845 return JVMTI_ERROR_NONE;
846 }
849 // Find new constant pool index value for old constant pool index value
850 // by seaching the index map. Returns zero (0) if there is no mapped
851 // value for the old constant pool index.
852 int VM_RedefineClasses::find_new_index(int old_index) {
853 if (_index_map_count == 0) {
854 // map is empty so nothing can be found
855 return 0;
856 }
858 if (old_index < 1 || old_index >= _index_map_p->length()) {
859 // The old_index is out of range so it is not mapped. This should
860 // not happen in regular constant pool merging use, but it can
861 // happen if a corrupt annotation is processed.
862 return 0;
863 }
865 int value = _index_map_p->at(old_index);
866 if (value == -1) {
867 // the old_index is not mapped
868 return 0;
869 }
871 return value;
872 } // end find_new_index()
875 // Find new bootstrap specifier index value for old bootstrap specifier index
876 // value by seaching the index map. Returns unused index (-1) if there is
877 // no mapped value for the old bootstrap specifier index.
878 int VM_RedefineClasses::find_new_operand_index(int old_index) {
879 if (_operands_index_map_count == 0) {
880 // map is empty so nothing can be found
881 return -1;
882 }
884 if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
885 // The old_index is out of range so it is not mapped.
886 // This should not happen in regular constant pool merging use.
887 return -1;
888 }
890 int value = _operands_index_map_p->at(old_index);
891 if (value == -1) {
892 // the old_index is not mapped
893 return -1;
894 }
896 return value;
897 } // end find_new_operand_index()
900 // Returns true if the current mismatch is due to a resolved/unresolved
901 // class pair. Otherwise, returns false.
902 bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
903 int index1, constantPoolHandle cp2, int index2) {
905 jbyte t1 = cp1->tag_at(index1).value();
906 if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
907 return false; // wrong entry type; not our special case
908 }
910 jbyte t2 = cp2->tag_at(index2).value();
911 if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
912 return false; // wrong entry type; not our special case
913 }
915 if (t1 == t2) {
916 return false; // not a mismatch; not our special case
917 }
919 char *s1 = cp1->klass_name_at(index1)->as_C_string();
920 char *s2 = cp2->klass_name_at(index2)->as_C_string();
921 if (strcmp(s1, s2) != 0) {
922 return false; // strings don't match; not our special case
923 }
925 return true; // made it through the gauntlet; this is our special case
926 } // end is_unresolved_class_mismatch()
929 jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
931 // For consistency allocate memory using os::malloc wrapper.
932 _scratch_classes = (Klass**)
933 os::malloc(sizeof(Klass*) * _class_count, mtClass);
934 if (_scratch_classes == NULL) {
935 return JVMTI_ERROR_OUT_OF_MEMORY;
936 }
937 // Zero initialize the _scratch_classes array.
938 for (int i = 0; i < _class_count; i++) {
939 _scratch_classes[i] = NULL;
940 }
942 ResourceMark rm(THREAD);
944 JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
945 // state can only be NULL if the current thread is exiting which
946 // should not happen since we're trying to do a RedefineClasses
947 guarantee(state != NULL, "exiting thread calling load_new_class_versions");
948 for (int i = 0; i < _class_count; i++) {
949 // Create HandleMark so that any handles created while loading new class
950 // versions are deleted. Constant pools are deallocated while merging
951 // constant pools
952 HandleMark hm(THREAD);
954 oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
955 // classes for primitives cannot be redefined
956 if (!is_modifiable_class(mirror)) {
957 return JVMTI_ERROR_UNMODIFIABLE_CLASS;
958 }
959 Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
960 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
961 Symbol* the_class_sym = the_class->name();
963 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
964 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
965 ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
966 the_class->external_name(), _class_load_kind,
967 os::available_memory() >> 10));
969 ClassFileStream st((u1*) _class_defs[i].class_bytes,
970 _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
972 // Parse the stream.
973 Handle the_class_loader(THREAD, the_class->class_loader());
974 Handle protection_domain(THREAD, the_class->protection_domain());
975 // Set redefined class handle in JvmtiThreadState class.
976 // This redefined class is sent to agent event handler for class file
977 // load hook event.
978 state->set_class_being_redefined(&the_class, _class_load_kind);
980 Klass* k = SystemDictionary::parse_stream(the_class_sym,
981 the_class_loader,
982 protection_domain,
983 &st,
984 THREAD);
985 // Clear class_being_redefined just to be sure.
986 state->clear_class_being_redefined();
988 // TODO: if this is retransform, and nothing changed we can skip it
990 instanceKlassHandle scratch_class (THREAD, k);
992 // Need to clean up allocated InstanceKlass if there's an error so assign
993 // the result here. Caller deallocates all the scratch classes in case of
994 // an error.
995 _scratch_classes[i] = k;
997 if (HAS_PENDING_EXCEPTION) {
998 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
999 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1000 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1001 ex_name->as_C_string()));
1002 CLEAR_PENDING_EXCEPTION;
1004 if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1005 return JVMTI_ERROR_UNSUPPORTED_VERSION;
1006 } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1007 return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1008 } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1009 return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1010 } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1011 // The message will be "XXX (wrong name: YYY)"
1012 return JVMTI_ERROR_NAMES_DONT_MATCH;
1013 } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1014 return JVMTI_ERROR_OUT_OF_MEMORY;
1015 } else { // Just in case more exceptions can be thrown..
1016 return JVMTI_ERROR_FAILS_VERIFICATION;
1017 }
1018 }
1020 // Ensure class is linked before redefine
1021 if (!the_class->is_linked()) {
1022 the_class->link_class(THREAD);
1023 if (HAS_PENDING_EXCEPTION) {
1024 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1025 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1026 RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1027 ex_name->as_C_string()));
1028 CLEAR_PENDING_EXCEPTION;
1029 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1030 return JVMTI_ERROR_OUT_OF_MEMORY;
1031 } else {
1032 return JVMTI_ERROR_INTERNAL;
1033 }
1034 }
1035 }
1037 // Do the validity checks in compare_and_normalize_class_versions()
1038 // before verifying the byte codes. By doing these checks first, we
1039 // limit the number of functions that require redirection from
1040 // the_class to scratch_class. In particular, we don't have to
1041 // modify JNI GetSuperclass() and thus won't change its performance.
1042 jvmtiError res = compare_and_normalize_class_versions(the_class,
1043 scratch_class);
1044 if (res != JVMTI_ERROR_NONE) {
1045 return res;
1046 }
1048 // verify what the caller passed us
1049 {
1050 // The bug 6214132 caused the verification to fail.
1051 // Information about the_class and scratch_class is temporarily
1052 // recorded into jvmtiThreadState. This data is used to redirect
1053 // the_class to scratch_class in the JVM_* functions called by the
1054 // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1055 // description.
1056 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1057 Verifier::verify(
1058 scratch_class, Verifier::ThrowException, true, THREAD);
1059 }
1061 if (HAS_PENDING_EXCEPTION) {
1062 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1063 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1064 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1065 ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1066 CLEAR_PENDING_EXCEPTION;
1067 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1068 return JVMTI_ERROR_OUT_OF_MEMORY;
1069 } else {
1070 // tell the caller the bytecodes are bad
1071 return JVMTI_ERROR_FAILS_VERIFICATION;
1072 }
1073 }
1075 res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1076 if (HAS_PENDING_EXCEPTION) {
1077 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1078 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1079 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1080 ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1081 CLEAR_PENDING_EXCEPTION;
1082 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1083 return JVMTI_ERROR_OUT_OF_MEMORY;
1084 } else {
1085 return JVMTI_ERROR_INTERNAL;
1086 }
1087 }
1089 if (VerifyMergedCPBytecodes) {
1090 // verify what we have done during constant pool merging
1091 {
1092 RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1093 Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1094 }
1096 if (HAS_PENDING_EXCEPTION) {
1097 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1098 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1099 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1100 ("verify_byte_codes post merge-CP exception: '%s'",
1101 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 // tell the caller that constant pool merging screwed up
1107 return JVMTI_ERROR_INTERNAL;
1108 }
1109 }
1110 }
1112 Rewriter::rewrite(scratch_class, THREAD);
1113 if (!HAS_PENDING_EXCEPTION) {
1114 scratch_class->link_methods(THREAD);
1115 }
1116 if (HAS_PENDING_EXCEPTION) {
1117 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1118 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1119 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1120 ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1121 CLEAR_PENDING_EXCEPTION;
1122 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1123 return JVMTI_ERROR_OUT_OF_MEMORY;
1124 } else {
1125 return JVMTI_ERROR_INTERNAL;
1126 }
1127 }
1129 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1130 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1131 ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1132 the_class->external_name(), os::available_memory() >> 10));
1133 }
1135 return JVMTI_ERROR_NONE;
1136 }
1139 // Map old_index to new_index as needed. scratch_cp is only needed
1140 // for RC_TRACE() calls.
1141 void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1142 int old_index, int new_index) {
1143 if (find_new_index(old_index) != 0) {
1144 // old_index is already mapped
1145 return;
1146 }
1148 if (old_index == new_index) {
1149 // no mapping is needed
1150 return;
1151 }
1153 _index_map_p->at_put(old_index, new_index);
1154 _index_map_count++;
1156 RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1157 scratch_cp->tag_at(old_index).value(), old_index, new_index));
1158 } // end map_index()
1161 // Map old_index to new_index as needed.
1162 void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1163 if (find_new_operand_index(old_index) != -1) {
1164 // old_index is already mapped
1165 return;
1166 }
1168 if (old_index == new_index) {
1169 // no mapping is needed
1170 return;
1171 }
1173 _operands_index_map_p->at_put(old_index, new_index);
1174 _operands_index_map_count++;
1176 RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1177 } // end map_index()
1180 // Merge old_cp and scratch_cp and return the results of the merge via
1181 // merge_cp_p. The number of entries in *merge_cp_p is returned via
1182 // merge_cp_length_p. The entries in old_cp occupy the same locations
1183 // in *merge_cp_p. Also creates a map of indices from entries in
1184 // scratch_cp to the corresponding entry in *merge_cp_p. Index map
1185 // entries are only created for entries in scratch_cp that occupy a
1186 // different location in *merged_cp_p.
1187 bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1188 constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1189 int *merge_cp_length_p, TRAPS) {
1191 if (merge_cp_p == NULL) {
1192 assert(false, "caller must provide scratch constantPool");
1193 return false; // robustness
1194 }
1195 if (merge_cp_length_p == NULL) {
1196 assert(false, "caller must provide scratch CP length");
1197 return false; // robustness
1198 }
1199 // Worst case we need old_cp->length() + scratch_cp()->length(),
1200 // but the caller might be smart so make sure we have at least
1201 // the minimum.
1202 if ((*merge_cp_p)->length() < old_cp->length()) {
1203 assert(false, "merge area too small");
1204 return false; // robustness
1205 }
1207 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1208 ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1209 scratch_cp->length()));
1211 {
1212 // Pass 0:
1213 // The old_cp is copied to *merge_cp_p; this means that any code
1214 // using old_cp does not have to change. This work looks like a
1215 // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1216 // handle one special case:
1217 // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1218 // This will make verification happy.
1220 int old_i; // index into old_cp
1222 // index zero (0) is not used in constantPools
1223 for (old_i = 1; old_i < old_cp->length(); old_i++) {
1224 // leave debugging crumb
1225 jbyte old_tag = old_cp->tag_at(old_i).value();
1226 switch (old_tag) {
1227 case JVM_CONSTANT_Class:
1228 case JVM_CONSTANT_UnresolvedClass:
1229 // revert the copy to JVM_CONSTANT_UnresolvedClass
1230 // May be resolving while calling this so do the same for
1231 // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1232 (*merge_cp_p)->unresolved_klass_at_put(old_i,
1233 old_cp->klass_name_at(old_i));
1234 break;
1236 case JVM_CONSTANT_Double:
1237 case JVM_CONSTANT_Long:
1238 // just copy the entry to *merge_cp_p, but double and long take
1239 // two constant pool entries
1240 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1241 old_i++;
1242 break;
1244 default:
1245 // just copy the entry to *merge_cp_p
1246 ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1247 break;
1248 }
1249 } // end for each old_cp entry
1251 ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1252 (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1254 // We don't need to sanity check that *merge_cp_length_p is within
1255 // *merge_cp_p bounds since we have the minimum on-entry check above.
1256 (*merge_cp_length_p) = old_i;
1257 }
1259 // merge_cp_len should be the same as old_cp->length() at this point
1260 // so this trace message is really a "warm-and-breathing" message.
1261 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1262 ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1264 int scratch_i; // index into scratch_cp
1265 {
1266 // Pass 1a:
1267 // Compare scratch_cp entries to the old_cp entries that we have
1268 // already copied to *merge_cp_p. In this pass, we are eliminating
1269 // exact duplicates (matching entry at same index) so we only
1270 // compare entries in the common indice range.
1271 int increment = 1;
1272 int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1273 for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1274 switch (scratch_cp->tag_at(scratch_i).value()) {
1275 case JVM_CONSTANT_Double:
1276 case JVM_CONSTANT_Long:
1277 // double and long take two constant pool entries
1278 increment = 2;
1279 break;
1281 default:
1282 increment = 1;
1283 break;
1284 }
1286 bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1287 scratch_i, CHECK_0);
1288 if (match) {
1289 // found a match at the same index so nothing more to do
1290 continue;
1291 } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1292 *merge_cp_p, scratch_i)) {
1293 // The mismatch in compare_entry_to() above is because of a
1294 // resolved versus unresolved class entry at the same index
1295 // with the same string value. Since Pass 0 reverted any
1296 // class entries to unresolved class entries in *merge_cp_p,
1297 // we go with the unresolved class entry.
1298 continue;
1299 }
1301 int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1302 CHECK_0);
1303 if (found_i != 0) {
1304 guarantee(found_i != scratch_i,
1305 "compare_entry_to() and find_matching_entry() do not agree");
1307 // Found a matching entry somewhere else in *merge_cp_p so
1308 // just need a mapping entry.
1309 map_index(scratch_cp, scratch_i, found_i);
1310 continue;
1311 }
1313 // The find_matching_entry() call above could fail to find a match
1314 // due to a resolved versus unresolved class or string entry situation
1315 // like we solved above with the is_unresolved_*_mismatch() calls.
1316 // However, we would have to call is_unresolved_*_mismatch() over
1317 // all of *merge_cp_p (potentially) and that doesn't seem to be
1318 // worth the time.
1320 // No match found so we have to append this entry and any unique
1321 // referenced entries to *merge_cp_p.
1322 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1323 CHECK_0);
1324 }
1325 }
1327 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1328 ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1329 *merge_cp_length_p, scratch_i, _index_map_count));
1331 if (scratch_i < scratch_cp->length()) {
1332 // Pass 1b:
1333 // old_cp is smaller than scratch_cp so there are entries in
1334 // scratch_cp that we have not yet processed. We take care of
1335 // those now.
1336 int increment = 1;
1337 for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1338 switch (scratch_cp->tag_at(scratch_i).value()) {
1339 case JVM_CONSTANT_Double:
1340 case JVM_CONSTANT_Long:
1341 // double and long take two constant pool entries
1342 increment = 2;
1343 break;
1345 default:
1346 increment = 1;
1347 break;
1348 }
1350 int found_i =
1351 scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1352 if (found_i != 0) {
1353 // Found a matching entry somewhere else in *merge_cp_p so
1354 // just need a mapping entry.
1355 map_index(scratch_cp, scratch_i, found_i);
1356 continue;
1357 }
1359 // No match found so we have to append this entry and any unique
1360 // referenced entries to *merge_cp_p.
1361 append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1362 CHECK_0);
1363 }
1365 RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1366 ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1367 *merge_cp_length_p, scratch_i, _index_map_count));
1368 }
1369 finalize_operands_merge(*merge_cp_p, THREAD);
1371 return true;
1372 } // end merge_constant_pools()
1375 // Scoped object to clean up the constant pool(s) created for merging
1376 class MergeCPCleaner {
1377 ClassLoaderData* _loader_data;
1378 ConstantPool* _cp;
1379 ConstantPool* _scratch_cp;
1380 public:
1381 MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1382 _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1383 ~MergeCPCleaner() {
1384 _loader_data->add_to_deallocate_list(_cp);
1385 if (_scratch_cp != NULL) {
1386 _loader_data->add_to_deallocate_list(_scratch_cp);
1387 }
1388 }
1389 void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1390 };
1392 // Merge constant pools between the_class and scratch_class and
1393 // potentially rewrite bytecodes in scratch_class to use the merged
1394 // constant pool.
1395 jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1396 instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1397 TRAPS) {
1398 // worst case merged constant pool length is old and new combined
1399 int merge_cp_length = the_class->constants()->length()
1400 + scratch_class->constants()->length();
1402 // Constant pools are not easily reused so we allocate a new one
1403 // each time.
1404 // merge_cp is created unsafe for concurrent GC processing. It
1405 // should be marked safe before discarding it. Even though
1406 // garbage, if it crosses a card boundary, it may be scanned
1407 // in order to find the start of the first complete object on the card.
1408 ClassLoaderData* loader_data = the_class->class_loader_data();
1409 ConstantPool* merge_cp_oop =
1410 ConstantPool::allocate(loader_data,
1411 merge_cp_length,
1412 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1413 MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1415 HandleMark hm(THREAD); // make sure handles are cleared before
1416 // MergeCPCleaner clears out merge_cp_oop
1417 constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1419 // Get constants() from the old class because it could have been rewritten
1420 // while we were at a safepoint allocating a new constant pool.
1421 constantPoolHandle old_cp(THREAD, the_class->constants());
1422 constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1424 // If the length changed, the class was redefined out from under us. Return
1425 // an error.
1426 if (merge_cp_length != the_class->constants()->length()
1427 + scratch_class->constants()->length()) {
1428 return JVMTI_ERROR_INTERNAL;
1429 }
1431 // Update the version number of the constant pool
1432 merge_cp->increment_and_save_version(old_cp->version());
1434 ResourceMark rm(THREAD);
1435 _index_map_count = 0;
1436 _index_map_p = new intArray(scratch_cp->length(), -1);
1438 _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1439 _operands_index_map_count = 0;
1440 _operands_index_map_p = new intArray(
1441 ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1443 // reference to the cp holder is needed for copy_operands()
1444 merge_cp->set_pool_holder(scratch_class());
1445 bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1446 &merge_cp_length, THREAD);
1447 merge_cp->set_pool_holder(NULL);
1449 if (!result) {
1450 // The merge can fail due to memory allocation failure or due
1451 // to robustness checks.
1452 return JVMTI_ERROR_INTERNAL;
1453 }
1455 RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1456 ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1458 if (_index_map_count == 0) {
1459 // there is nothing to map between the new and merged constant pools
1461 if (old_cp->length() == scratch_cp->length()) {
1462 // The old and new constant pools are the same length and the
1463 // index map is empty. This means that the three constant pools
1464 // are equivalent (but not the same). Unfortunately, the new
1465 // constant pool has not gone through link resolution nor have
1466 // the new class bytecodes gone through constant pool cache
1467 // rewriting so we can't use the old constant pool with the new
1468 // class.
1470 // toss the merged constant pool at return
1471 } else if (old_cp->length() < scratch_cp->length()) {
1472 // The old constant pool has fewer entries than the new constant
1473 // pool and the index map is empty. This means the new constant
1474 // pool is a superset of the old constant pool. However, the old
1475 // class bytecodes have already gone through constant pool cache
1476 // rewriting so we can't use the new constant pool with the old
1477 // class.
1479 // toss the merged constant pool at return
1480 } else {
1481 // The old constant pool has more entries than the new constant
1482 // pool and the index map is empty. This means that both the old
1483 // and merged constant pools are supersets of the new constant
1484 // pool.
1486 // Replace the new constant pool with a shrunken copy of the
1487 // merged constant pool
1488 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1489 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1490 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1491 // It can't be cleaned up while there are handles to it.
1492 cp_cleaner.add_scratch_cp(scratch_cp());
1493 }
1494 } else {
1495 if (RC_TRACE_ENABLED(0x00040000)) {
1496 // don't want to loop unless we are tracing
1497 int count = 0;
1498 for (int i = 1; i < _index_map_p->length(); i++) {
1499 int value = _index_map_p->at(i);
1501 if (value != -1) {
1502 RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1503 ("index_map[%d]: old=%d new=%d", count, i, value));
1504 count++;
1505 }
1506 }
1507 }
1509 // We have entries mapped between the new and merged constant pools
1510 // so we have to rewrite some constant pool references.
1511 if (!rewrite_cp_refs(scratch_class, THREAD)) {
1512 return JVMTI_ERROR_INTERNAL;
1513 }
1515 // Replace the new constant pool with a shrunken copy of the
1516 // merged constant pool so now the rewritten bytecodes have
1517 // valid references; the previous new constant pool will get
1518 // GCed.
1519 set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1520 CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1521 // The new constant pool replaces scratch_cp so have cleaner clean it up.
1522 // It can't be cleaned up while there are handles to it.
1523 cp_cleaner.add_scratch_cp(scratch_cp());
1524 }
1526 return JVMTI_ERROR_NONE;
1527 } // end merge_cp_and_rewrite()
1530 // Rewrite constant pool references in klass scratch_class.
1531 bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1532 TRAPS) {
1534 // rewrite constant pool references in the methods:
1535 if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1536 // propagate failure back to caller
1537 return false;
1538 }
1540 // rewrite constant pool references in the class_annotations:
1541 if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1542 // propagate failure back to caller
1543 return false;
1544 }
1546 // rewrite constant pool references in the fields_annotations:
1547 if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1548 // propagate failure back to caller
1549 return false;
1550 }
1552 // rewrite constant pool references in the methods_annotations:
1553 if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1554 // propagate failure back to caller
1555 return false;
1556 }
1558 // rewrite constant pool references in the methods_parameter_annotations:
1559 if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1560 THREAD)) {
1561 // propagate failure back to caller
1562 return false;
1563 }
1565 // rewrite constant pool references in the methods_default_annotations:
1566 if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1567 THREAD)) {
1568 // propagate failure back to caller
1569 return false;
1570 }
1572 // rewrite source file name index:
1573 u2 source_file_name_idx = scratch_class->source_file_name_index();
1574 if (source_file_name_idx != 0) {
1575 u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1576 if (new_source_file_name_idx != 0) {
1577 scratch_class->set_source_file_name_index(new_source_file_name_idx);
1578 }
1579 }
1581 // rewrite class generic signature index:
1582 u2 generic_signature_index = scratch_class->generic_signature_index();
1583 if (generic_signature_index != 0) {
1584 u2 new_generic_signature_index = find_new_index(generic_signature_index);
1585 if (new_generic_signature_index != 0) {
1586 scratch_class->set_generic_signature_index(new_generic_signature_index);
1587 }
1588 }
1590 return true;
1591 } // end rewrite_cp_refs()
1593 // Rewrite constant pool references in the methods.
1594 bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1595 instanceKlassHandle scratch_class, TRAPS) {
1597 Array<Method*>* methods = scratch_class->methods();
1599 if (methods == NULL || methods->length() == 0) {
1600 // no methods so nothing to do
1601 return true;
1602 }
1604 // rewrite constant pool references in the methods:
1605 for (int i = methods->length() - 1; i >= 0; i--) {
1606 methodHandle method(THREAD, methods->at(i));
1607 methodHandle new_method;
1608 rewrite_cp_refs_in_method(method, &new_method, THREAD);
1609 if (!new_method.is_null()) {
1610 // the method has been replaced so save the new method version
1611 // even in the case of an exception. original method is on the
1612 // deallocation list.
1613 methods->at_put(i, new_method());
1614 }
1615 if (HAS_PENDING_EXCEPTION) {
1616 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1617 // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1618 RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1619 ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1620 // Need to clear pending exception here as the super caller sets
1621 // the JVMTI_ERROR_INTERNAL if the returned value is false.
1622 CLEAR_PENDING_EXCEPTION;
1623 return false;
1624 }
1625 }
1627 return true;
1628 }
1631 // Rewrite constant pool references in the specific method. This code
1632 // was adapted from Rewriter::rewrite_method().
1633 void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1634 methodHandle *new_method_p, TRAPS) {
1636 *new_method_p = methodHandle(); // default is no new method
1638 // We cache a pointer to the bytecodes here in code_base. If GC
1639 // moves the Method*, then the bytecodes will also move which
1640 // will likely cause a crash. We create a No_Safepoint_Verifier
1641 // object to detect whether we pass a possible safepoint in this
1642 // code block.
1643 No_Safepoint_Verifier nsv;
1645 // Bytecodes and their length
1646 address code_base = method->code_base();
1647 int code_length = method->code_size();
1649 int bc_length;
1650 for (int bci = 0; bci < code_length; bci += bc_length) {
1651 address bcp = code_base + bci;
1652 Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1654 bc_length = Bytecodes::length_for(c);
1655 if (bc_length == 0) {
1656 // More complicated bytecodes report a length of zero so
1657 // we have to try again a slightly different way.
1658 bc_length = Bytecodes::length_at(method(), bcp);
1659 }
1661 assert(bc_length != 0, "impossible bytecode length");
1663 switch (c) {
1664 case Bytecodes::_ldc:
1665 {
1666 int cp_index = *(bcp + 1);
1667 int new_index = find_new_index(cp_index);
1669 if (StressLdcRewrite && new_index == 0) {
1670 // If we are stressing ldc -> ldc_w rewriting, then we
1671 // always need a new_index value.
1672 new_index = cp_index;
1673 }
1674 if (new_index != 0) {
1675 // the original index is mapped so we have more work to do
1676 if (!StressLdcRewrite && new_index <= max_jubyte) {
1677 // The new value can still use ldc instead of ldc_w
1678 // unless we are trying to stress ldc -> ldc_w rewriting
1679 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1680 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1681 bcp, cp_index, new_index));
1682 *(bcp + 1) = new_index;
1683 } else {
1684 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1685 ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1686 Bytecodes::name(c), bcp, cp_index, new_index));
1687 // the new value needs ldc_w instead of ldc
1688 u_char inst_buffer[4]; // max instruction size is 4 bytes
1689 bcp = (address)inst_buffer;
1690 // construct new instruction sequence
1691 *bcp = Bytecodes::_ldc_w;
1692 bcp++;
1693 // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1694 // See comment below for difference between put_Java_u2()
1695 // and put_native_u2().
1696 Bytes::put_Java_u2(bcp, new_index);
1698 Relocator rc(method, NULL /* no RelocatorListener needed */);
1699 methodHandle m;
1700 {
1701 Pause_No_Safepoint_Verifier pnsv(&nsv);
1703 // ldc is 2 bytes and ldc_w is 3 bytes
1704 m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1705 }
1707 // return the new method so that the caller can update
1708 // the containing class
1709 *new_method_p = method = m;
1710 // switch our bytecode processing loop from the old method
1711 // to the new method
1712 code_base = method->code_base();
1713 code_length = method->code_size();
1714 bcp = code_base + bci;
1715 c = (Bytecodes::Code)(*bcp);
1716 bc_length = Bytecodes::length_for(c);
1717 assert(bc_length != 0, "sanity check");
1718 } // end we need ldc_w instead of ldc
1719 } // end if there is a mapped index
1720 } break;
1722 // these bytecodes have a two-byte constant pool index
1723 case Bytecodes::_anewarray : // fall through
1724 case Bytecodes::_checkcast : // fall through
1725 case Bytecodes::_getfield : // fall through
1726 case Bytecodes::_getstatic : // fall through
1727 case Bytecodes::_instanceof : // fall through
1728 case Bytecodes::_invokedynamic : // fall through
1729 case Bytecodes::_invokeinterface: // fall through
1730 case Bytecodes::_invokespecial : // fall through
1731 case Bytecodes::_invokestatic : // fall through
1732 case Bytecodes::_invokevirtual : // fall through
1733 case Bytecodes::_ldc_w : // fall through
1734 case Bytecodes::_ldc2_w : // fall through
1735 case Bytecodes::_multianewarray : // fall through
1736 case Bytecodes::_new : // fall through
1737 case Bytecodes::_putfield : // fall through
1738 case Bytecodes::_putstatic :
1739 {
1740 address p = bcp + 1;
1741 int cp_index = Bytes::get_Java_u2(p);
1742 int new_index = find_new_index(cp_index);
1743 if (new_index != 0) {
1744 // the original index is mapped so update w/ new value
1745 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1746 ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1747 bcp, cp_index, new_index));
1748 // Rewriter::rewrite_method() uses put_native_u2() in this
1749 // situation because it is reusing the constant pool index
1750 // location for a native index into the ConstantPoolCache.
1751 // Since we are updating the constant pool index prior to
1752 // verification and ConstantPoolCache initialization, we
1753 // need to keep the new index in Java byte order.
1754 Bytes::put_Java_u2(p, new_index);
1755 }
1756 } break;
1757 }
1758 } // end for each bytecode
1760 // We also need to rewrite the parameter name indexes, if there is
1761 // method parameter data present
1762 if(method->has_method_parameters()) {
1763 const int len = method->method_parameters_length();
1764 MethodParametersElement* elem = method->method_parameters_start();
1766 for (int i = 0; i < len; i++) {
1767 const u2 cp_index = elem[i].name_cp_index;
1768 const u2 new_cp_index = find_new_index(cp_index);
1769 if (new_cp_index != 0) {
1770 elem[i].name_cp_index = new_cp_index;
1771 }
1772 }
1773 }
1774 } // end rewrite_cp_refs_in_method()
1777 // Rewrite constant pool references in the class_annotations field.
1778 bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1779 instanceKlassHandle scratch_class, TRAPS) {
1781 AnnotationArray* class_annotations = scratch_class->class_annotations();
1782 if (class_annotations == NULL || class_annotations->length() == 0) {
1783 // no class_annotations so nothing to do
1784 return true;
1785 }
1787 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1788 ("class_annotations length=%d", class_annotations->length()));
1790 int byte_i = 0; // byte index into class_annotations
1791 return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1792 THREAD);
1793 }
1796 // Rewrite constant pool references in an annotations typeArray. This
1797 // "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1798 // that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1799 //
1800 // annotations_typeArray {
1801 // u2 num_annotations;
1802 // annotation annotations[num_annotations];
1803 // }
1804 //
1805 bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1806 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1808 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1809 // not enough room for num_annotations field
1810 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1811 ("length() is too small for num_annotations field"));
1812 return false;
1813 }
1815 u2 num_annotations = Bytes::get_Java_u2((address)
1816 annotations_typeArray->adr_at(byte_i_ref));
1817 byte_i_ref += 2;
1819 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1820 ("num_annotations=%d", num_annotations));
1822 int calc_num_annotations = 0;
1823 for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1824 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1825 byte_i_ref, THREAD)) {
1826 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1827 ("bad annotation_struct at %d", calc_num_annotations));
1828 // propagate failure back to caller
1829 return false;
1830 }
1831 }
1832 assert(num_annotations == calc_num_annotations, "sanity check");
1834 return true;
1835 } // end rewrite_cp_refs_in_annotations_typeArray()
1838 // Rewrite constant pool references in the annotation struct portion of
1839 // an annotations_typeArray. This "structure" is from section 4.8.15 of
1840 // the 2nd-edition of the VM spec:
1841 //
1842 // struct annotation {
1843 // u2 type_index;
1844 // u2 num_element_value_pairs;
1845 // {
1846 // u2 element_name_index;
1847 // element_value value;
1848 // } element_value_pairs[num_element_value_pairs];
1849 // }
1850 //
1851 bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1852 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1853 if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1854 // not enough room for smallest annotation_struct
1855 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1856 ("length() is too small for annotation_struct"));
1857 return false;
1858 }
1860 u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1861 byte_i_ref, "mapped old type_index=%d", THREAD);
1863 u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1864 annotations_typeArray->adr_at(byte_i_ref));
1865 byte_i_ref += 2;
1867 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1868 ("type_index=%d num_element_value_pairs=%d", type_index,
1869 num_element_value_pairs));
1871 int calc_num_element_value_pairs = 0;
1872 for (; calc_num_element_value_pairs < num_element_value_pairs;
1873 calc_num_element_value_pairs++) {
1874 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1875 // not enough room for another element_name_index, let alone
1876 // the rest of another component
1877 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1878 ("length() is too small for element_name_index"));
1879 return false;
1880 }
1882 u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1883 annotations_typeArray, byte_i_ref,
1884 "mapped old element_name_index=%d", THREAD);
1886 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1887 ("element_name_index=%d", element_name_index));
1889 if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1890 byte_i_ref, THREAD)) {
1891 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1892 ("bad element_value at %d", calc_num_element_value_pairs));
1893 // propagate failure back to caller
1894 return false;
1895 }
1896 } // end for each component
1897 assert(num_element_value_pairs == calc_num_element_value_pairs,
1898 "sanity check");
1900 return true;
1901 } // end rewrite_cp_refs_in_annotation_struct()
1904 // Rewrite a constant pool reference at the current position in
1905 // annotations_typeArray if needed. Returns the original constant
1906 // pool reference if a rewrite was not needed or the new constant
1907 // pool reference if a rewrite was needed.
1908 PRAGMA_DIAG_PUSH
1909 PRAGMA_FORMAT_NONLITERAL_IGNORED
1910 u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1911 AnnotationArray* annotations_typeArray, int &byte_i_ref,
1912 const char * trace_mesg, TRAPS) {
1914 address cp_index_addr = (address)
1915 annotations_typeArray->adr_at(byte_i_ref);
1916 u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1917 u2 new_cp_index = find_new_index(old_cp_index);
1918 if (new_cp_index != 0) {
1919 RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1920 Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1921 old_cp_index = new_cp_index;
1922 }
1923 byte_i_ref += 2;
1924 return old_cp_index;
1925 }
1926 PRAGMA_DIAG_POP
1929 // Rewrite constant pool references in the element_value portion of an
1930 // annotations_typeArray. This "structure" is from section 4.8.15.1 of
1931 // the 2nd-edition of the VM spec:
1932 //
1933 // struct element_value {
1934 // u1 tag;
1935 // union {
1936 // u2 const_value_index;
1937 // {
1938 // u2 type_name_index;
1939 // u2 const_name_index;
1940 // } enum_const_value;
1941 // u2 class_info_index;
1942 // annotation annotation_value;
1943 // struct {
1944 // u2 num_values;
1945 // element_value values[num_values];
1946 // } array_value;
1947 // } value;
1948 // }
1949 //
1950 bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1951 AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1953 if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1954 // not enough room for a tag let alone the rest of an element_value
1955 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1956 ("length() is too small for a tag"));
1957 return false;
1958 }
1960 u1 tag = annotations_typeArray->at(byte_i_ref);
1961 byte_i_ref++;
1962 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1964 switch (tag) {
1965 // These BaseType tag values are from Table 4.2 in VM spec:
1966 case 'B': // byte
1967 case 'C': // char
1968 case 'D': // double
1969 case 'F': // float
1970 case 'I': // int
1971 case 'J': // long
1972 case 'S': // short
1973 case 'Z': // boolean
1975 // The remaining tag values are from Table 4.8 in the 2nd-edition of
1976 // the VM spec:
1977 case 's':
1978 {
1979 // For the above tag values (including the BaseType values),
1980 // value.const_value_index is right union field.
1982 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1983 // not enough room for a const_value_index
1984 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1985 ("length() is too small for a const_value_index"));
1986 return false;
1987 }
1989 u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1990 annotations_typeArray, byte_i_ref,
1991 "mapped old const_value_index=%d", THREAD);
1993 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1994 ("const_value_index=%d", const_value_index));
1995 } break;
1997 case 'e':
1998 {
1999 // for the above tag value, value.enum_const_value is right union field
2001 if ((byte_i_ref + 4) > annotations_typeArray->length()) {
2002 // not enough room for a enum_const_value
2003 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2004 ("length() is too small for a enum_const_value"));
2005 return false;
2006 }
2008 u2 type_name_index = rewrite_cp_ref_in_annotation_data(
2009 annotations_typeArray, byte_i_ref,
2010 "mapped old type_name_index=%d", THREAD);
2012 u2 const_name_index = rewrite_cp_ref_in_annotation_data(
2013 annotations_typeArray, byte_i_ref,
2014 "mapped old const_name_index=%d", THREAD);
2016 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2017 ("type_name_index=%d const_name_index=%d", type_name_index,
2018 const_name_index));
2019 } break;
2021 case 'c':
2022 {
2023 // for the above tag value, value.class_info_index is right union field
2025 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2026 // not enough room for a class_info_index
2027 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2028 ("length() is too small for a class_info_index"));
2029 return false;
2030 }
2032 u2 class_info_index = rewrite_cp_ref_in_annotation_data(
2033 annotations_typeArray, byte_i_ref,
2034 "mapped old class_info_index=%d", THREAD);
2036 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2037 ("class_info_index=%d", class_info_index));
2038 } break;
2040 case '@':
2041 // For the above tag value, value.attr_value is the right union
2042 // field. This is a nested annotation.
2043 if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
2044 byte_i_ref, THREAD)) {
2045 // propagate failure back to caller
2046 return false;
2047 }
2048 break;
2050 case '[':
2051 {
2052 if ((byte_i_ref + 2) > annotations_typeArray->length()) {
2053 // not enough room for a num_values field
2054 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2055 ("length() is too small for a num_values field"));
2056 return false;
2057 }
2059 // For the above tag value, value.array_value is the right union
2060 // field. This is an array of nested element_value.
2061 u2 num_values = Bytes::get_Java_u2((address)
2062 annotations_typeArray->adr_at(byte_i_ref));
2063 byte_i_ref += 2;
2064 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
2066 int calc_num_values = 0;
2067 for (; calc_num_values < num_values; calc_num_values++) {
2068 if (!rewrite_cp_refs_in_element_value(
2069 annotations_typeArray, byte_i_ref, THREAD)) {
2070 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2071 ("bad nested element_value at %d", calc_num_values));
2072 // propagate failure back to caller
2073 return false;
2074 }
2075 }
2076 assert(num_values == calc_num_values, "sanity check");
2077 } break;
2079 default:
2080 RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
2081 return false;
2082 } // end decode tag field
2084 return true;
2085 } // end rewrite_cp_refs_in_element_value()
2088 // Rewrite constant pool references in a fields_annotations field.
2089 bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
2090 instanceKlassHandle scratch_class, TRAPS) {
2092 Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
2094 if (fields_annotations == NULL || fields_annotations->length() == 0) {
2095 // no fields_annotations so nothing to do
2096 return true;
2097 }
2099 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2100 ("fields_annotations length=%d", fields_annotations->length()));
2102 for (int i = 0; i < fields_annotations->length(); i++) {
2103 AnnotationArray* field_annotations = fields_annotations->at(i);
2104 if (field_annotations == NULL || field_annotations->length() == 0) {
2105 // this field does not have any annotations so skip it
2106 continue;
2107 }
2109 int byte_i = 0; // byte index into field_annotations
2110 if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
2111 THREAD)) {
2112 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2113 ("bad field_annotations at %d", i));
2114 // propagate failure back to caller
2115 return false;
2116 }
2117 }
2119 return true;
2120 } // end rewrite_cp_refs_in_fields_annotations()
2123 // Rewrite constant pool references in a methods_annotations field.
2124 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
2125 instanceKlassHandle scratch_class, TRAPS) {
2127 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2128 Method* m = scratch_class->methods()->at(i);
2129 AnnotationArray* method_annotations = m->constMethod()->method_annotations();
2131 if (method_annotations == NULL || method_annotations->length() == 0) {
2132 // this method does not have any annotations so skip it
2133 continue;
2134 }
2136 int byte_i = 0; // byte index into method_annotations
2137 if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
2138 THREAD)) {
2139 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2140 ("bad method_annotations at %d", i));
2141 // propagate failure back to caller
2142 return false;
2143 }
2144 }
2146 return true;
2147 } // end rewrite_cp_refs_in_methods_annotations()
2150 // Rewrite constant pool references in a methods_parameter_annotations
2151 // field. This "structure" is adapted from the
2152 // RuntimeVisibleParameterAnnotations_attribute described in section
2153 // 4.8.17 of the 2nd-edition of the VM spec:
2154 //
2155 // methods_parameter_annotations_typeArray {
2156 // u1 num_parameters;
2157 // {
2158 // u2 num_annotations;
2159 // annotation annotations[num_annotations];
2160 // } parameter_annotations[num_parameters];
2161 // }
2162 //
2163 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
2164 instanceKlassHandle scratch_class, TRAPS) {
2166 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2167 Method* m = scratch_class->methods()->at(i);
2168 AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
2169 if (method_parameter_annotations == NULL
2170 || method_parameter_annotations->length() == 0) {
2171 // this method does not have any parameter annotations so skip it
2172 continue;
2173 }
2175 if (method_parameter_annotations->length() < 1) {
2176 // not enough room for a num_parameters field
2177 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2178 ("length() is too small for a num_parameters field at %d", i));
2179 return false;
2180 }
2182 int byte_i = 0; // byte index into method_parameter_annotations
2184 u1 num_parameters = method_parameter_annotations->at(byte_i);
2185 byte_i++;
2187 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2188 ("num_parameters=%d", num_parameters));
2190 int calc_num_parameters = 0;
2191 for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
2192 if (!rewrite_cp_refs_in_annotations_typeArray(
2193 method_parameter_annotations, byte_i, THREAD)) {
2194 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2195 ("bad method_parameter_annotations at %d", calc_num_parameters));
2196 // propagate failure back to caller
2197 return false;
2198 }
2199 }
2200 assert(num_parameters == calc_num_parameters, "sanity check");
2201 }
2203 return true;
2204 } // end rewrite_cp_refs_in_methods_parameter_annotations()
2207 // Rewrite constant pool references in a methods_default_annotations
2208 // field. This "structure" is adapted from the AnnotationDefault_attribute
2209 // that is described in section 4.8.19 of the 2nd-edition of the VM spec:
2210 //
2211 // methods_default_annotations_typeArray {
2212 // element_value default_value;
2213 // }
2214 //
2215 bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
2216 instanceKlassHandle scratch_class, TRAPS) {
2218 for (int i = 0; i < scratch_class->methods()->length(); i++) {
2219 Method* m = scratch_class->methods()->at(i);
2220 AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
2221 if (method_default_annotations == NULL
2222 || method_default_annotations->length() == 0) {
2223 // this method does not have any default annotations so skip it
2224 continue;
2225 }
2227 int byte_i = 0; // byte index into method_default_annotations
2229 if (!rewrite_cp_refs_in_element_value(
2230 method_default_annotations, byte_i, THREAD)) {
2231 RC_TRACE_WITH_THREAD(0x02000000, THREAD,
2232 ("bad default element_value at %d", i));
2233 // propagate failure back to caller
2234 return false;
2235 }
2236 }
2238 return true;
2239 } // end rewrite_cp_refs_in_methods_default_annotations()
2242 // Rewrite constant pool references in the method's stackmap table.
2243 // These "structures" are adapted from the StackMapTable_attribute that
2244 // is described in section 4.8.4 of the 6.0 version of the VM spec
2245 // (dated 2005.10.26):
2246 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2247 //
2248 // stack_map {
2249 // u2 number_of_entries;
2250 // stack_map_frame entries[number_of_entries];
2251 // }
2252 //
2253 void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
2254 methodHandle method, TRAPS) {
2256 if (!method->has_stackmap_table()) {
2257 return;
2258 }
2260 AnnotationArray* stackmap_data = method->stackmap_data();
2261 address stackmap_p = (address)stackmap_data->adr_at(0);
2262 address stackmap_end = stackmap_p + stackmap_data->length();
2264 assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
2265 u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
2266 stackmap_p += 2;
2268 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2269 ("number_of_entries=%u", number_of_entries));
2271 // walk through each stack_map_frame
2272 u2 calc_number_of_entries = 0;
2273 for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
2274 // The stack_map_frame structure is a u1 frame_type followed by
2275 // 0 or more bytes of data:
2276 //
2277 // union stack_map_frame {
2278 // same_frame;
2279 // same_locals_1_stack_item_frame;
2280 // same_locals_1_stack_item_frame_extended;
2281 // chop_frame;
2282 // same_frame_extended;
2283 // append_frame;
2284 // full_frame;
2285 // }
2287 assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
2288 // The Linux compiler does not like frame_type to be u1 or u2. It
2289 // issues the following warning for the first if-statement below:
2290 //
2291 // "warning: comparison is always true due to limited range of data type"
2292 //
2293 u4 frame_type = *stackmap_p;
2294 stackmap_p++;
2296 // same_frame {
2297 // u1 frame_type = SAME; /* 0-63 */
2298 // }
2299 if (frame_type >= 0 && frame_type <= 63) {
2300 // nothing more to do for same_frame
2301 }
2303 // same_locals_1_stack_item_frame {
2304 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
2305 // verification_type_info stack[1];
2306 // }
2307 else if (frame_type >= 64 && frame_type <= 127) {
2308 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2309 calc_number_of_entries, frame_type, THREAD);
2310 }
2312 // reserved for future use
2313 else if (frame_type >= 128 && frame_type <= 246) {
2314 // nothing more to do for reserved frame_types
2315 }
2317 // same_locals_1_stack_item_frame_extended {
2318 // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
2319 // u2 offset_delta;
2320 // verification_type_info stack[1];
2321 // }
2322 else if (frame_type == 247) {
2323 stackmap_p += 2;
2324 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2325 calc_number_of_entries, frame_type, THREAD);
2326 }
2328 // chop_frame {
2329 // u1 frame_type = CHOP; /* 248-250 */
2330 // u2 offset_delta;
2331 // }
2332 else if (frame_type >= 248 && frame_type <= 250) {
2333 stackmap_p += 2;
2334 }
2336 // same_frame_extended {
2337 // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
2338 // u2 offset_delta;
2339 // }
2340 else if (frame_type == 251) {
2341 stackmap_p += 2;
2342 }
2344 // append_frame {
2345 // u1 frame_type = APPEND; /* 252-254 */
2346 // u2 offset_delta;
2347 // verification_type_info locals[frame_type - 251];
2348 // }
2349 else if (frame_type >= 252 && frame_type <= 254) {
2350 assert(stackmap_p + 2 <= stackmap_end,
2351 "no room for offset_delta");
2352 stackmap_p += 2;
2353 u1 len = frame_type - 251;
2354 for (u1 i = 0; i < len; i++) {
2355 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2356 calc_number_of_entries, frame_type, THREAD);
2357 }
2358 }
2360 // full_frame {
2361 // u1 frame_type = FULL_FRAME; /* 255 */
2362 // u2 offset_delta;
2363 // u2 number_of_locals;
2364 // verification_type_info locals[number_of_locals];
2365 // u2 number_of_stack_items;
2366 // verification_type_info stack[number_of_stack_items];
2367 // }
2368 else if (frame_type == 255) {
2369 assert(stackmap_p + 2 + 2 <= stackmap_end,
2370 "no room for smallest full_frame");
2371 stackmap_p += 2;
2373 u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
2374 stackmap_p += 2;
2376 for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
2377 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2378 calc_number_of_entries, frame_type, THREAD);
2379 }
2381 // Use the largest size for the number_of_stack_items, but only get
2382 // the right number of bytes.
2383 u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
2384 stackmap_p += 2;
2386 for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
2387 rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
2388 calc_number_of_entries, frame_type, THREAD);
2389 }
2390 }
2391 } // end while there is a stack_map_frame
2392 assert(number_of_entries == calc_number_of_entries, "sanity check");
2393 } // end rewrite_cp_refs_in_stack_map_table()
2396 // Rewrite constant pool references in the verification type info
2397 // portion of the method's stackmap table. These "structures" are
2398 // adapted from the StackMapTable_attribute that is described in
2399 // section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
2400 // file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
2401 //
2402 // The verification_type_info structure is a u1 tag followed by 0 or
2403 // more bytes of data:
2404 //
2405 // union verification_type_info {
2406 // Top_variable_info;
2407 // Integer_variable_info;
2408 // Float_variable_info;
2409 // Long_variable_info;
2410 // Double_variable_info;
2411 // Null_variable_info;
2412 // UninitializedThis_variable_info;
2413 // Object_variable_info;
2414 // Uninitialized_variable_info;
2415 // }
2416 //
2417 void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
2418 address& stackmap_p_ref, address stackmap_end, u2 frame_i,
2419 u1 frame_type, TRAPS) {
2421 assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
2422 u1 tag = *stackmap_p_ref;
2423 stackmap_p_ref++;
2425 switch (tag) {
2426 // Top_variable_info {
2427 // u1 tag = ITEM_Top; /* 0 */
2428 // }
2429 // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
2430 case 0: // fall through
2432 // Integer_variable_info {
2433 // u1 tag = ITEM_Integer; /* 1 */
2434 // }
2435 case ITEM_Integer: // fall through
2437 // Float_variable_info {
2438 // u1 tag = ITEM_Float; /* 2 */
2439 // }
2440 case ITEM_Float: // fall through
2442 // Double_variable_info {
2443 // u1 tag = ITEM_Double; /* 3 */
2444 // }
2445 case ITEM_Double: // fall through
2447 // Long_variable_info {
2448 // u1 tag = ITEM_Long; /* 4 */
2449 // }
2450 case ITEM_Long: // fall through
2452 // Null_variable_info {
2453 // u1 tag = ITEM_Null; /* 5 */
2454 // }
2455 case ITEM_Null: // fall through
2457 // UninitializedThis_variable_info {
2458 // u1 tag = ITEM_UninitializedThis; /* 6 */
2459 // }
2460 case ITEM_UninitializedThis:
2461 // nothing more to do for the above tag types
2462 break;
2464 // Object_variable_info {
2465 // u1 tag = ITEM_Object; /* 7 */
2466 // u2 cpool_index;
2467 // }
2468 case ITEM_Object:
2469 {
2470 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
2471 u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
2472 u2 new_cp_index = find_new_index(cpool_index);
2473 if (new_cp_index != 0) {
2474 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2475 ("mapped old cpool_index=%d", cpool_index));
2476 Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
2477 cpool_index = new_cp_index;
2478 }
2479 stackmap_p_ref += 2;
2481 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2482 ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
2483 frame_type, cpool_index));
2484 } break;
2486 // Uninitialized_variable_info {
2487 // u1 tag = ITEM_Uninitialized; /* 8 */
2488 // u2 offset;
2489 // }
2490 case ITEM_Uninitialized:
2491 assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
2492 stackmap_p_ref += 2;
2493 break;
2495 default:
2496 RC_TRACE_WITH_THREAD(0x04000000, THREAD,
2497 ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
2498 ShouldNotReachHere();
2499 break;
2500 } // end switch (tag)
2501 } // end rewrite_cp_refs_in_verification_type_info()
2504 // Change the constant pool associated with klass scratch_class to
2505 // scratch_cp. If shrink is true, then scratch_cp_length elements
2506 // are copied from scratch_cp to a smaller constant pool and the
2507 // smaller constant pool is associated with scratch_class.
2508 void VM_RedefineClasses::set_new_constant_pool(
2509 ClassLoaderData* loader_data,
2510 instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
2511 int scratch_cp_length, TRAPS) {
2512 assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
2514 // scratch_cp is a merged constant pool and has enough space for a
2515 // worst case merge situation. We want to associate the minimum
2516 // sized constant pool with the klass to save space.
2517 ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
2518 constantPoolHandle smaller_cp(THREAD, cp);
2520 // preserve version() value in the smaller copy
2521 int version = scratch_cp->version();
2522 assert(version != 0, "sanity check");
2523 smaller_cp->set_version(version);
2525 // attach klass to new constant pool
2526 // reference to the cp holder is needed for copy_operands()
2527 smaller_cp->set_pool_holder(scratch_class());
2529 scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
2530 if (HAS_PENDING_EXCEPTION) {
2531 // Exception is handled in the caller
2532 loader_data->add_to_deallocate_list(smaller_cp());
2533 return;
2534 }
2535 scratch_cp = smaller_cp;
2537 // attach new constant pool to klass
2538 scratch_class->set_constants(scratch_cp());
2540 int i; // for portability
2542 // update each field in klass to use new constant pool indices as needed
2543 for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
2544 jshort cur_index = fs.name_index();
2545 jshort new_index = find_new_index(cur_index);
2546 if (new_index != 0) {
2547 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2548 ("field-name_index change: %d to %d", cur_index, new_index));
2549 fs.set_name_index(new_index);
2550 }
2551 cur_index = fs.signature_index();
2552 new_index = find_new_index(cur_index);
2553 if (new_index != 0) {
2554 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2555 ("field-signature_index change: %d to %d", cur_index, new_index));
2556 fs.set_signature_index(new_index);
2557 }
2558 cur_index = fs.initval_index();
2559 new_index = find_new_index(cur_index);
2560 if (new_index != 0) {
2561 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2562 ("field-initval_index change: %d to %d", cur_index, new_index));
2563 fs.set_initval_index(new_index);
2564 }
2565 cur_index = fs.generic_signature_index();
2566 new_index = find_new_index(cur_index);
2567 if (new_index != 0) {
2568 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2569 ("field-generic_signature change: %d to %d", cur_index, new_index));
2570 fs.set_generic_signature_index(new_index);
2571 }
2572 } // end for each field
2574 // Update constant pool indices in the inner classes info to use
2575 // new constant indices as needed. The inner classes info is a
2576 // quadruple:
2577 // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
2578 InnerClassesIterator iter(scratch_class);
2579 for (; !iter.done(); iter.next()) {
2580 int cur_index = iter.inner_class_info_index();
2581 if (cur_index == 0) {
2582 continue; // JVM spec. allows null inner class refs so skip it
2583 }
2584 int new_index = find_new_index(cur_index);
2585 if (new_index != 0) {
2586 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2587 ("inner_class_info change: %d to %d", cur_index, new_index));
2588 iter.set_inner_class_info_index(new_index);
2589 }
2590 cur_index = iter.outer_class_info_index();
2591 new_index = find_new_index(cur_index);
2592 if (new_index != 0) {
2593 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2594 ("outer_class_info change: %d to %d", cur_index, new_index));
2595 iter.set_outer_class_info_index(new_index);
2596 }
2597 cur_index = iter.inner_name_index();
2598 new_index = find_new_index(cur_index);
2599 if (new_index != 0) {
2600 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2601 ("inner_name change: %d to %d", cur_index, new_index));
2602 iter.set_inner_name_index(new_index);
2603 }
2604 } // end for each inner class
2606 // Attach each method in klass to the new constant pool and update
2607 // to use new constant pool indices as needed:
2608 Array<Method*>* methods = scratch_class->methods();
2609 for (i = methods->length() - 1; i >= 0; i--) {
2610 methodHandle method(THREAD, methods->at(i));
2611 method->set_constants(scratch_cp());
2613 int new_index = find_new_index(method->name_index());
2614 if (new_index != 0) {
2615 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2616 ("method-name_index change: %d to %d", method->name_index(),
2617 new_index));
2618 method->set_name_index(new_index);
2619 }
2620 new_index = find_new_index(method->signature_index());
2621 if (new_index != 0) {
2622 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2623 ("method-signature_index change: %d to %d",
2624 method->signature_index(), new_index));
2625 method->set_signature_index(new_index);
2626 }
2627 new_index = find_new_index(method->generic_signature_index());
2628 if (new_index != 0) {
2629 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2630 ("method-generic_signature_index change: %d to %d",
2631 method->generic_signature_index(), new_index));
2632 method->set_generic_signature_index(new_index);
2633 }
2635 // Update constant pool indices in the method's checked exception
2636 // table to use new constant indices as needed.
2637 int cext_length = method->checked_exceptions_length();
2638 if (cext_length > 0) {
2639 CheckedExceptionElement * cext_table =
2640 method->checked_exceptions_start();
2641 for (int j = 0; j < cext_length; j++) {
2642 int cur_index = cext_table[j].class_cp_index;
2643 int new_index = find_new_index(cur_index);
2644 if (new_index != 0) {
2645 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2646 ("cext-class_cp_index change: %d to %d", cur_index, new_index));
2647 cext_table[j].class_cp_index = (u2)new_index;
2648 }
2649 } // end for each checked exception table entry
2650 } // end if there are checked exception table entries
2652 // Update each catch type index in the method's exception table
2653 // to use new constant pool indices as needed. The exception table
2654 // holds quadruple entries of the form:
2655 // (beg_bci, end_bci, handler_bci, klass_index)
2657 ExceptionTable ex_table(method());
2658 int ext_length = ex_table.length();
2660 for (int j = 0; j < ext_length; j ++) {
2661 int cur_index = ex_table.catch_type_index(j);
2662 int new_index = find_new_index(cur_index);
2663 if (new_index != 0) {
2664 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2665 ("ext-klass_index change: %d to %d", cur_index, new_index));
2666 ex_table.set_catch_type_index(j, new_index);
2667 }
2668 } // end for each exception table entry
2670 // Update constant pool indices in the method's local variable
2671 // table to use new constant indices as needed. The local variable
2672 // table hold sextuple entries of the form:
2673 // (start_pc, length, name_index, descriptor_index, signature_index, slot)
2674 int lvt_length = method->localvariable_table_length();
2675 if (lvt_length > 0) {
2676 LocalVariableTableElement * lv_table =
2677 method->localvariable_table_start();
2678 for (int j = 0; j < lvt_length; j++) {
2679 int cur_index = lv_table[j].name_cp_index;
2680 int new_index = find_new_index(cur_index);
2681 if (new_index != 0) {
2682 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2683 ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
2684 lv_table[j].name_cp_index = (u2)new_index;
2685 }
2686 cur_index = lv_table[j].descriptor_cp_index;
2687 new_index = find_new_index(cur_index);
2688 if (new_index != 0) {
2689 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2690 ("lvt-descriptor_cp_index change: %d to %d", cur_index,
2691 new_index));
2692 lv_table[j].descriptor_cp_index = (u2)new_index;
2693 }
2694 cur_index = lv_table[j].signature_cp_index;
2695 new_index = find_new_index(cur_index);
2696 if (new_index != 0) {
2697 RC_TRACE_WITH_THREAD(0x00080000, THREAD,
2698 ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
2699 lv_table[j].signature_cp_index = (u2)new_index;
2700 }
2701 } // end for each local variable table entry
2702 } // end if there are local variable table entries
2704 rewrite_cp_refs_in_stack_map_table(method, THREAD);
2705 } // end for each method
2706 } // end set_new_constant_pool()
2709 // Unevolving classes may point to methods of the_class directly
2710 // from their constant pool caches, itables, and/or vtables. We
2711 // use the ClassLoaderDataGraph::classes_do() facility and this helper
2712 // to fix up these pointers.
2714 // Adjust cpools and vtables closure
2715 void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
2717 // This is a very busy routine. We don't want too much tracing
2718 // printed out.
2719 bool trace_name_printed = false;
2721 // Very noisy: only enable this call if you are trying to determine
2722 // that a specific class gets found by this routine.
2723 // RC_TRACE macro has an embedded ResourceMark
2724 // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
2725 // ("adjust check: name=%s", k->external_name()));
2726 // trace_name_printed = true;
2728 // If the class being redefined is java.lang.Object, we need to fix all
2729 // array class vtables also
2730 if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
2731 k->vtable()->adjust_method_entries(_matching_old_methods,
2732 _matching_new_methods,
2733 _matching_methods_length,
2734 &trace_name_printed);
2735 } else if (k->oop_is_instance()) {
2736 HandleMark hm(_thread);
2737 InstanceKlass *ik = InstanceKlass::cast(k);
2739 // HotSpot specific optimization! HotSpot does not currently
2740 // support delegation from the bootstrap class loader to a
2741 // user-defined class loader. This means that if the bootstrap
2742 // class loader is the initiating class loader, then it will also
2743 // be the defining class loader. This also means that classes
2744 // loaded by the bootstrap class loader cannot refer to classes
2745 // loaded by a user-defined class loader. Note: a user-defined
2746 // class loader can delegate to the bootstrap class loader.
2747 //
2748 // If the current class being redefined has a user-defined class
2749 // loader as its defining class loader, then we can skip all
2750 // classes loaded by the bootstrap class loader.
2751 bool is_user_defined =
2752 InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
2753 if (is_user_defined && ik->class_loader() == NULL) {
2754 return;
2755 }
2757 // Fix the vtable embedded in the_class and subclasses of the_class,
2758 // if one exists. We discard scratch_class and we don't keep an
2759 // InstanceKlass around to hold obsolete methods so we don't have
2760 // any other InstanceKlass embedded vtables to update. The vtable
2761 // holds the Method*s for virtual (but not final) methods.
2762 // Default methods, or concrete methods in interfaces are stored
2763 // in the vtable, so if an interface changes we need to check
2764 // adjust_method_entries() for every InstanceKlass, which will also
2765 // adjust the default method vtable indices.
2766 // We also need to adjust any default method entries that are
2767 // not yet in the vtable, because the vtable setup is in progress.
2768 // This must be done after we adjust the default_methods and
2769 // default_vtable_indices for methods already in the vtable.
2770 if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
2771 || ik->is_subtype_of(_the_class_oop))) {
2772 // ik->vtable() creates a wrapper object; rm cleans it up
2773 ResourceMark rm(_thread);
2774 ik->vtable()->adjust_method_entries(_matching_old_methods,
2775 _matching_new_methods,
2776 _matching_methods_length,
2777 &trace_name_printed);
2778 ik->adjust_default_methods(_matching_old_methods,
2779 _matching_new_methods,
2780 _matching_methods_length,
2781 &trace_name_printed);
2782 }
2784 // If the current class has an itable and we are either redefining an
2785 // interface or if the current class is a subclass of the_class, then
2786 // we potentially have to fix the itable. If we are redefining an
2787 // interface, then we have to call adjust_method_entries() for
2788 // every InstanceKlass that has an itable since there isn't a
2789 // subclass relationship between an interface and an InstanceKlass.
2790 if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
2791 || ik->is_subclass_of(_the_class_oop))) {
2792 // ik->itable() creates a wrapper object; rm cleans it up
2793 ResourceMark rm(_thread);
2794 ik->itable()->adjust_method_entries(_matching_old_methods,
2795 _matching_new_methods,
2796 _matching_methods_length,
2797 &trace_name_printed);
2798 }
2800 // The constant pools in other classes (other_cp) can refer to
2801 // methods in the_class. We have to update method information in
2802 // other_cp's cache. If other_cp has a previous version, then we
2803 // have to repeat the process for each previous version. The
2804 // constant pool cache holds the Method*s for non-virtual
2805 // methods and for virtual, final methods.
2806 //
2807 // Special case: if the current class is the_class, then new_cp
2808 // has already been attached to the_class and old_cp has already
2809 // been added as a previous version. The new_cp doesn't have any
2810 // cached references to old methods so it doesn't need to be
2811 // updated. We can simply start with the previous version(s) in
2812 // that case.
2813 constantPoolHandle other_cp;
2814 ConstantPoolCache* cp_cache;
2816 if (ik != _the_class_oop) {
2817 // this klass' constant pool cache may need adjustment
2818 other_cp = constantPoolHandle(ik->constants());
2819 cp_cache = other_cp->cache();
2820 if (cp_cache != NULL) {
2821 cp_cache->adjust_method_entries(_matching_old_methods,
2822 _matching_new_methods,
2823 _matching_methods_length,
2824 &trace_name_printed);
2825 }
2826 }
2828 // the previous versions' constant pool caches may need adjustment
2829 PreviousVersionWalker pvw(_thread, ik);
2830 for (PreviousVersionNode * pv_node = pvw.next_previous_version();
2831 pv_node != NULL; pv_node = pvw.next_previous_version()) {
2832 other_cp = pv_node->prev_constant_pool();
2833 cp_cache = other_cp->cache();
2834 if (cp_cache != NULL) {
2835 cp_cache->adjust_method_entries(_matching_old_methods,
2836 _matching_new_methods,
2837 _matching_methods_length,
2838 &trace_name_printed);
2839 }
2840 }
2841 }
2842 }
2844 void VM_RedefineClasses::update_jmethod_ids() {
2845 for (int j = 0; j < _matching_methods_length; ++j) {
2846 Method* old_method = _matching_old_methods[j];
2847 jmethodID jmid = old_method->find_jmethod_id_or_null();
2848 if (jmid != NULL) {
2849 // There is a jmethodID, change it to point to the new method
2850 methodHandle new_method_h(_matching_new_methods[j]);
2851 Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
2852 assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
2853 "should be replaced");
2854 }
2855 }
2856 }
2858 void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
2859 BitMap *emcp_methods, int * emcp_method_count_p) {
2860 *emcp_method_count_p = 0;
2861 int obsolete_count = 0;
2862 int old_index = 0;
2863 for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
2864 Method* old_method = _matching_old_methods[j];
2865 Method* new_method = _matching_new_methods[j];
2866 Method* old_array_method;
2868 // Maintain an old_index into the _old_methods array by skipping
2869 // deleted methods
2870 while ((old_array_method = _old_methods->at(old_index)) != old_method) {
2871 ++old_index;
2872 }
2874 if (MethodComparator::methods_EMCP(old_method, new_method)) {
2875 // The EMCP definition from JSR-163 requires the bytecodes to be
2876 // the same with the exception of constant pool indices which may
2877 // differ. However, the constants referred to by those indices
2878 // must be the same.
2879 //
2880 // We use methods_EMCP() for comparison since constant pool
2881 // merging can remove duplicate constant pool entries that were
2882 // present in the old method and removed from the rewritten new
2883 // method. A faster binary comparison function would consider the
2884 // old and new methods to be different when they are actually
2885 // EMCP.
2886 //
2887 // The old and new methods are EMCP and you would think that we
2888 // could get rid of one of them here and now and save some space.
2889 // However, the concept of EMCP only considers the bytecodes and
2890 // the constant pool entries in the comparison. Other things,
2891 // e.g., the line number table (LNT) or the local variable table
2892 // (LVT) don't count in the comparison. So the new (and EMCP)
2893 // method can have a new LNT that we need so we can't just
2894 // overwrite the new method with the old method.
2895 //
2896 // When this routine is called, we have already attached the new
2897 // methods to the_class so the old methods are effectively
2898 // overwritten. However, if an old method is still executing,
2899 // then the old method cannot be collected until sometime after
2900 // the old method call has returned. So the overwriting of old
2901 // methods by new methods will save us space except for those
2902 // (hopefully few) old methods that are still executing.
2903 //
2904 // A method refers to a ConstMethod* and this presents another
2905 // possible avenue to space savings. The ConstMethod* in the
2906 // new method contains possibly new attributes (LNT, LVT, etc).
2907 // At first glance, it seems possible to save space by replacing
2908 // the ConstMethod* in the old method with the ConstMethod*
2909 // from the new method. The old and new methods would share the
2910 // same ConstMethod* and we would save the space occupied by
2911 // the old ConstMethod*. However, the ConstMethod* contains
2912 // a back reference to the containing method. Sharing the
2913 // ConstMethod* between two methods could lead to confusion in
2914 // the code that uses the back reference. This would lead to
2915 // brittle code that could be broken in non-obvious ways now or
2916 // in the future.
2917 //
2918 // Another possibility is to copy the ConstMethod* from the new
2919 // method to the old method and then overwrite the new method with
2920 // the old method. Since the ConstMethod* contains the bytecodes
2921 // for the method embedded in the oop, this option would change
2922 // the bytecodes out from under any threads executing the old
2923 // method and make the thread's bcp invalid. Since EMCP requires
2924 // that the bytecodes be the same modulo constant pool indices, it
2925 // is straight forward to compute the correct new bcp in the new
2926 // ConstMethod* from the old bcp in the old ConstMethod*. The
2927 // time consuming part would be searching all the frames in all
2928 // of the threads to find all of the calls to the old method.
2929 //
2930 // It looks like we will have to live with the limited savings
2931 // that we get from effectively overwriting the old methods
2932 // when the new methods are attached to the_class.
2934 // track which methods are EMCP for add_previous_version() call
2935 emcp_methods->set_bit(old_index);
2936 (*emcp_method_count_p)++;
2938 // An EMCP method is _not_ obsolete. An obsolete method has a
2939 // different jmethodID than the current method. An EMCP method
2940 // has the same jmethodID as the current method. Having the
2941 // same jmethodID for all EMCP versions of a method allows for
2942 // a consistent view of the EMCP methods regardless of which
2943 // EMCP method you happen to have in hand. For example, a
2944 // breakpoint set in one EMCP method will work for all EMCP
2945 // versions of the method including the current one.
2946 } else {
2947 // mark obsolete methods as such
2948 old_method->set_is_obsolete();
2949 obsolete_count++;
2951 // obsolete methods need a unique idnum so they become new entries in
2952 // the jmethodID cache in InstanceKlass
2953 u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
2954 if (num != ConstMethod::UNSET_IDNUM) {
2955 old_method->set_method_idnum(num);
2956 }
2958 // With tracing we try not to "yack" too much. The position of
2959 // this trace assumes there are fewer obsolete methods than
2960 // EMCP methods.
2961 RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
2962 old_method->name()->as_C_string(),
2963 old_method->signature()->as_C_string()));
2964 }
2965 old_method->set_is_old();
2966 }
2967 for (int i = 0; i < _deleted_methods_length; ++i) {
2968 Method* old_method = _deleted_methods[i];
2970 assert(!old_method->has_vtable_index(),
2971 "cannot delete methods with vtable entries");;
2973 // Mark all deleted methods as old and obsolete
2974 old_method->set_is_old();
2975 old_method->set_is_obsolete();
2976 ++obsolete_count;
2977 // With tracing we try not to "yack" too much. The position of
2978 // this trace assumes there are fewer obsolete methods than
2979 // EMCP methods.
2980 RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
2981 old_method->name()->as_C_string(),
2982 old_method->signature()->as_C_string()));
2983 }
2984 assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
2985 "sanity check");
2986 RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
2987 obsolete_count));
2988 }
2990 // This internal class transfers the native function registration from old methods
2991 // to new methods. It is designed to handle both the simple case of unchanged
2992 // native methods and the complex cases of native method prefixes being added and/or
2993 // removed.
2994 // It expects only to be used during the VM_RedefineClasses op (a safepoint).
2995 //
2996 // This class is used after the new methods have been installed in "the_class".
2997 //
2998 // So, for example, the following must be handled. Where 'm' is a method and
2999 // a number followed by an underscore is a prefix.
3000 //
3001 // Old Name New Name
3002 // Simple transfer to new method m -> m
3003 // Add prefix m -> 1_m
3004 // Remove prefix 1_m -> m
3005 // Simultaneous add of prefixes m -> 3_2_1_m
3006 // Simultaneous removal of prefixes 3_2_1_m -> m
3007 // Simultaneous add and remove 1_m -> 2_m
3008 // Same, caused by prefix removal only 3_2_1_m -> 3_2_m
3009 //
3010 class TransferNativeFunctionRegistration {
3011 private:
3012 instanceKlassHandle the_class;
3013 int prefix_count;
3014 char** prefixes;
3016 // Recursively search the binary tree of possibly prefixed method names.
3017 // Iteration could be used if all agents were well behaved. Full tree walk is
3018 // more resilent to agents not cleaning up intermediate methods.
3019 // Branch at each depth in the binary tree is:
3020 // (1) without the prefix.
3021 // (2) with the prefix.
3022 // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
3023 Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
3024 Symbol* signature) {
3025 TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
3026 if (name_symbol != NULL) {
3027 Method* method = the_class()->lookup_method(name_symbol, signature);
3028 if (method != NULL) {
3029 // Even if prefixed, intermediate methods must exist.
3030 if (method->is_native()) {
3031 // Wahoo, we found a (possibly prefixed) version of the method, return it.
3032 return method;
3033 }
3034 if (depth < prefix_count) {
3035 // Try applying further prefixes (other than this one).
3036 method = search_prefix_name_space(depth+1, name_str, name_len, signature);
3037 if (method != NULL) {
3038 return method; // found
3039 }
3041 // Try adding this prefix to the method name and see if it matches
3042 // another method name.
3043 char* prefix = prefixes[depth];
3044 size_t prefix_len = strlen(prefix);
3045 size_t trial_len = name_len + prefix_len;
3046 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
3047 strcpy(trial_name_str, prefix);
3048 strcat(trial_name_str, name_str);
3049 method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
3050 signature);
3051 if (method != NULL) {
3052 // If found along this branch, it was prefixed, mark as such
3053 method->set_is_prefixed_native();
3054 return method; // found
3055 }
3056 }
3057 }
3058 }
3059 return NULL; // This whole branch bore nothing
3060 }
3062 // Return the method name with old prefixes stripped away.
3063 char* method_name_without_prefixes(Method* method) {
3064 Symbol* name = method->name();
3065 char* name_str = name->as_utf8();
3067 // Old prefixing may be defunct, strip prefixes, if any.
3068 for (int i = prefix_count-1; i >= 0; i--) {
3069 char* prefix = prefixes[i];
3070 size_t prefix_len = strlen(prefix);
3071 if (strncmp(prefix, name_str, prefix_len) == 0) {
3072 name_str += prefix_len;
3073 }
3074 }
3075 return name_str;
3076 }
3078 // Strip any prefixes off the old native method, then try to find a
3079 // (possibly prefixed) new native that matches it.
3080 Method* strip_and_search_for_new_native(Method* method) {
3081 ResourceMark rm;
3082 char* name_str = method_name_without_prefixes(method);
3083 return search_prefix_name_space(0, name_str, strlen(name_str),
3084 method->signature());
3085 }
3087 public:
3089 // Construct a native method transfer processor for this class.
3090 TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
3091 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
3093 the_class = _the_class;
3094 prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
3095 }
3097 // Attempt to transfer any of the old or deleted methods that are native
3098 void transfer_registrations(Method** old_methods, int methods_length) {
3099 for (int j = 0; j < methods_length; j++) {
3100 Method* old_method = old_methods[j];
3102 if (old_method->is_native() && old_method->has_native_function()) {
3103 Method* new_method = strip_and_search_for_new_native(old_method);
3104 if (new_method != NULL) {
3105 // Actually set the native function in the new method.
3106 // Redefine does not send events (except CFLH), certainly not this
3107 // behind the scenes re-registration.
3108 new_method->set_native_function(old_method->native_function(),
3109 !Method::native_bind_event_is_interesting);
3110 }
3111 }
3112 }
3113 }
3114 };
3116 // Don't lose the association between a native method and its JNI function.
3117 void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
3118 TransferNativeFunctionRegistration transfer(the_class);
3119 transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
3120 transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
3121 }
3123 // Deoptimize all compiled code that depends on this class.
3124 //
3125 // If the can_redefine_classes capability is obtained in the onload
3126 // phase then the compiler has recorded all dependencies from startup.
3127 // In that case we need only deoptimize and throw away all compiled code
3128 // that depends on the class.
3129 //
3130 // If can_redefine_classes is obtained sometime after the onload
3131 // phase then the dependency information may be incomplete. In that case
3132 // the first call to RedefineClasses causes all compiled code to be
3133 // thrown away. As can_redefine_classes has been obtained then
3134 // all future compilations will record dependencies so second and
3135 // subsequent calls to RedefineClasses need only throw away code
3136 // that depends on the class.
3137 //
3138 void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
3139 assert_locked_or_safepoint(Compile_lock);
3141 // All dependencies have been recorded from startup or this is a second or
3142 // subsequent use of RedefineClasses
3143 if (JvmtiExport::all_dependencies_are_recorded()) {
3144 Universe::flush_evol_dependents_on(k_h);
3145 } else {
3146 CodeCache::mark_all_nmethods_for_deoptimization();
3148 ResourceMark rm(THREAD);
3149 DeoptimizationMarker dm;
3151 // Deoptimize all activations depending on marked nmethods
3152 Deoptimization::deoptimize_dependents();
3154 // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
3155 CodeCache::make_marked_nmethods_not_entrant();
3157 // From now on we know that the dependency information is complete
3158 JvmtiExport::set_all_dependencies_are_recorded(true);
3159 }
3160 }
3162 void VM_RedefineClasses::compute_added_deleted_matching_methods() {
3163 Method* old_method;
3164 Method* new_method;
3166 _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3167 _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3168 _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
3169 _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
3171 _matching_methods_length = 0;
3172 _deleted_methods_length = 0;
3173 _added_methods_length = 0;
3175 int nj = 0;
3176 int oj = 0;
3177 while (true) {
3178 if (oj >= _old_methods->length()) {
3179 if (nj >= _new_methods->length()) {
3180 break; // we've looked at everything, done
3181 }
3182 // New method at the end
3183 new_method = _new_methods->at(nj);
3184 _added_methods[_added_methods_length++] = new_method;
3185 ++nj;
3186 } else if (nj >= _new_methods->length()) {
3187 // Old method, at the end, is deleted
3188 old_method = _old_methods->at(oj);
3189 _deleted_methods[_deleted_methods_length++] = old_method;
3190 ++oj;
3191 } else {
3192 old_method = _old_methods->at(oj);
3193 new_method = _new_methods->at(nj);
3194 if (old_method->name() == new_method->name()) {
3195 if (old_method->signature() == new_method->signature()) {
3196 _matching_old_methods[_matching_methods_length ] = old_method;
3197 _matching_new_methods[_matching_methods_length++] = new_method;
3198 ++nj;
3199 ++oj;
3200 } else {
3201 // added overloaded have already been moved to the end,
3202 // so this is a deleted overloaded method
3203 _deleted_methods[_deleted_methods_length++] = old_method;
3204 ++oj;
3205 }
3206 } else { // names don't match
3207 if (old_method->name()->fast_compare(new_method->name()) > 0) {
3208 // new method
3209 _added_methods[_added_methods_length++] = new_method;
3210 ++nj;
3211 } else {
3212 // deleted method
3213 _deleted_methods[_deleted_methods_length++] = old_method;
3214 ++oj;
3215 }
3216 }
3217 }
3218 }
3219 assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
3220 assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
3221 }
3224 void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
3225 instanceKlassHandle scratch_class) {
3226 // Since there is currently no rewriting of type annotations indexes
3227 // into the CP, we null out type annotations on scratch_class before
3228 // we swap annotations with the_class rather than facing the
3229 // possibility of shipping annotations with broken indexes to
3230 // Java-land.
3231 ClassLoaderData* loader_data = scratch_class->class_loader_data();
3232 AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
3233 if (new_class_type_annotations != NULL) {
3234 MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
3235 scratch_class->annotations()->set_class_type_annotations(NULL);
3236 }
3237 Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
3238 if (new_field_type_annotations != NULL) {
3239 Annotations::free_contents(loader_data, new_field_type_annotations);
3240 scratch_class->annotations()->set_fields_type_annotations(NULL);
3241 }
3243 // Swap annotation fields values
3244 Annotations* old_annotations = the_class->annotations();
3245 the_class->set_annotations(scratch_class->annotations());
3246 scratch_class->set_annotations(old_annotations);
3247 }
3250 // Install the redefinition of a class:
3251 // - house keeping (flushing breakpoints and caches, deoptimizing
3252 // dependent compiled code)
3253 // - replacing parts in the_class with parts from scratch_class
3254 // - adding a weak reference to track the obsolete but interesting
3255 // parts of the_class
3256 // - adjusting constant pool caches and vtables in other classes
3257 // that refer to methods in the_class. These adjustments use the
3258 // ClassLoaderDataGraph::classes_do() facility which only allows
3259 // a helper method to be specified. The interesting parameters
3260 // that we would like to pass to the helper method are saved in
3261 // static global fields in the VM operation.
3262 void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
3263 Klass* scratch_class_oop, TRAPS) {
3265 HandleMark hm(THREAD); // make sure handles from this call are freed
3266 RC_TIMER_START(_timer_rsc_phase1);
3268 instanceKlassHandle scratch_class(scratch_class_oop);
3270 oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
3271 Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
3272 instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
3274 // Remove all breakpoints in methods of this class
3275 JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
3276 jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
3278 // Deoptimize all compiled code that depends on this class
3279 flush_dependent_code(the_class, THREAD);
3281 _old_methods = the_class->methods();
3282 _new_methods = scratch_class->methods();
3283 _the_class_oop = the_class_oop;
3284 compute_added_deleted_matching_methods();
3285 update_jmethod_ids();
3287 // Attach new constant pool to the original klass. The original
3288 // klass still refers to the old constant pool (for now).
3289 scratch_class->constants()->set_pool_holder(the_class());
3291 #if 0
3292 // In theory, with constant pool merging in place we should be able
3293 // to save space by using the new, merged constant pool in place of
3294 // the old constant pool(s). By "pool(s)" I mean the constant pool in
3295 // the klass version we are replacing now and any constant pool(s) in
3296 // previous versions of klass. Nice theory, doesn't work in practice.
3297 // When this code is enabled, even simple programs throw NullPointer
3298 // exceptions. I'm guessing that this is caused by some constant pool
3299 // cache difference between the new, merged constant pool and the
3300 // constant pool that was just being used by the klass. I'm keeping
3301 // this code around to archive the idea, but the code has to remain
3302 // disabled for now.
3304 // Attach each old method to the new constant pool. This can be
3305 // done here since we are past the bytecode verification and
3306 // constant pool optimization phases.
3307 for (int i = _old_methods->length() - 1; i >= 0; i--) {
3308 Method* method = _old_methods->at(i);
3309 method->set_constants(scratch_class->constants());
3310 }
3312 {
3313 // walk all previous versions of the klass
3314 InstanceKlass *ik = (InstanceKlass *)the_class();
3315 PreviousVersionWalker pvw(ik);
3316 instanceKlassHandle ikh;
3317 do {
3318 ikh = pvw.next_previous_version();
3319 if (!ikh.is_null()) {
3320 ik = ikh();
3322 // attach previous version of klass to the new constant pool
3323 ik->set_constants(scratch_class->constants());
3325 // Attach each method in the previous version of klass to the
3326 // new constant pool
3327 Array<Method*>* prev_methods = ik->methods();
3328 for (int i = prev_methods->length() - 1; i >= 0; i--) {
3329 Method* method = prev_methods->at(i);
3330 method->set_constants(scratch_class->constants());
3331 }
3332 }
3333 } while (!ikh.is_null());
3334 }
3335 #endif
3337 // Replace methods and constantpool
3338 the_class->set_methods(_new_methods);
3339 scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
3340 // and to be able to undo operation easily.
3342 ConstantPool* old_constants = the_class->constants();
3343 the_class->set_constants(scratch_class->constants());
3344 scratch_class->set_constants(old_constants); // See the previous comment.
3345 #if 0
3346 // We are swapping the guts of "the new class" with the guts of "the
3347 // class". Since the old constant pool has just been attached to "the
3348 // new class", it seems logical to set the pool holder in the old
3349 // constant pool also. However, doing this will change the observable
3350 // class hierarchy for any old methods that are still executing. A
3351 // method can query the identity of its "holder" and this query uses
3352 // the method's constant pool link to find the holder. The change in
3353 // holding class from "the class" to "the new class" can confuse
3354 // things.
3355 //
3356 // Setting the old constant pool's holder will also cause
3357 // verification done during vtable initialization below to fail.
3358 // During vtable initialization, the vtable's class is verified to be
3359 // a subtype of the method's holder. The vtable's class is "the
3360 // class" and the method's holder is gotten from the constant pool
3361 // link in the method itself. For "the class"'s directly implemented
3362 // methods, the method holder is "the class" itself (as gotten from
3363 // the new constant pool). The check works fine in this case. The
3364 // check also works fine for methods inherited from super classes.
3365 //
3366 // Miranda methods are a little more complicated. A miranda method is
3367 // provided by an interface when the class implementing the interface
3368 // does not provide its own method. These interfaces are implemented
3369 // internally as an InstanceKlass. These special instanceKlasses
3370 // share the constant pool of the class that "implements" the
3371 // interface. By sharing the constant pool, the method holder of a
3372 // miranda method is the class that "implements" the interface. In a
3373 // non-redefine situation, the subtype check works fine. However, if
3374 // the old constant pool's pool holder is modified, then the check
3375 // fails because there is no class hierarchy relationship between the
3376 // vtable's class and "the new class".
3378 old_constants->set_pool_holder(scratch_class());
3379 #endif
3381 // track which methods are EMCP for add_previous_version() call below
3382 BitMap emcp_methods(_old_methods->length());
3383 int emcp_method_count = 0;
3384 emcp_methods.clear(); // clears 0..(length() - 1)
3385 check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
3386 transfer_old_native_function_registrations(the_class);
3388 // The class file bytes from before any retransformable agents mucked
3389 // with them was cached on the scratch class, move to the_class.
3390 // Note: we still want to do this if nothing needed caching since it
3391 // should get cleared in the_class too.
3392 if (the_class->get_cached_class_file_bytes() == 0) {
3393 // the_class doesn't have a cache yet so copy it
3394 the_class->set_cached_class_file(scratch_class->get_cached_class_file());
3395 }
3396 #ifndef PRODUCT
3397 else {
3398 assert(the_class->get_cached_class_file_bytes() ==
3399 scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
3400 assert(the_class->get_cached_class_file_len() ==
3401 scratch_class->get_cached_class_file_len(), "cache lens must match");
3402 }
3403 #endif
3405 // NULL out in scratch class to not delete twice. The class to be redefined
3406 // always owns these bytes.
3407 scratch_class->set_cached_class_file(NULL);
3409 // Replace inner_classes
3410 Array<u2>* old_inner_classes = the_class->inner_classes();
3411 the_class->set_inner_classes(scratch_class->inner_classes());
3412 scratch_class->set_inner_classes(old_inner_classes);
3414 // Initialize the vtable and interface table after
3415 // methods have been rewritten
3416 {
3417 ResourceMark rm(THREAD);
3418 // no exception should happen here since we explicitly
3419 // do not check loader constraints.
3420 // compare_and_normalize_class_versions has already checked:
3421 // - classloaders unchanged, signatures unchanged
3422 // - all instanceKlasses for redefined classes reused & contents updated
3423 the_class->vtable()->initialize_vtable(false, THREAD);
3424 the_class->itable()->initialize_itable(false, THREAD);
3425 assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
3426 }
3428 // Leave arrays of jmethodIDs and itable index cache unchanged
3430 // Copy the "source file name" attribute from new class version
3431 the_class->set_source_file_name_index(
3432 scratch_class->source_file_name_index());
3434 // Copy the "source debug extension" attribute from new class version
3435 the_class->set_source_debug_extension(
3436 scratch_class->source_debug_extension(),
3437 scratch_class->source_debug_extension() == NULL ? 0 :
3438 (int)strlen(scratch_class->source_debug_extension()));
3440 // Use of javac -g could be different in the old and the new
3441 if (scratch_class->access_flags().has_localvariable_table() !=
3442 the_class->access_flags().has_localvariable_table()) {
3444 AccessFlags flags = the_class->access_flags();
3445 if (scratch_class->access_flags().has_localvariable_table()) {
3446 flags.set_has_localvariable_table();
3447 } else {
3448 flags.clear_has_localvariable_table();
3449 }
3450 the_class->set_access_flags(flags);
3451 }
3453 swap_annotations(the_class, scratch_class);
3455 // Replace minor version number of class file
3456 u2 old_minor_version = the_class->minor_version();
3457 the_class->set_minor_version(scratch_class->minor_version());
3458 scratch_class->set_minor_version(old_minor_version);
3460 // Replace major version number of class file
3461 u2 old_major_version = the_class->major_version();
3462 the_class->set_major_version(scratch_class->major_version());
3463 scratch_class->set_major_version(old_major_version);
3465 // Replace CP indexes for class and name+type of enclosing method
3466 u2 old_class_idx = the_class->enclosing_method_class_index();
3467 u2 old_method_idx = the_class->enclosing_method_method_index();
3468 the_class->set_enclosing_method_indices(
3469 scratch_class->enclosing_method_class_index(),
3470 scratch_class->enclosing_method_method_index());
3471 scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
3473 // keep track of previous versions of this class
3474 the_class->add_previous_version(scratch_class, &emcp_methods,
3475 emcp_method_count);
3477 RC_TIMER_STOP(_timer_rsc_phase1);
3478 RC_TIMER_START(_timer_rsc_phase2);
3480 // Adjust constantpool caches and vtables for all classes
3481 // that reference methods of the evolved class.
3482 AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
3483 ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
3485 // JSR-292 support
3486 MemberNameTable* mnt = the_class->member_names();
3487 if (mnt != NULL) {
3488 bool trace_name_printed = false;
3489 mnt->adjust_method_entries(_matching_old_methods,
3490 _matching_new_methods,
3491 _matching_methods_length,
3492 &trace_name_printed);
3493 }
3495 // Fix Resolution Error table also to remove old constant pools
3496 SystemDictionary::delete_resolution_error(old_constants);
3498 if (the_class->oop_map_cache() != NULL) {
3499 // Flush references to any obsolete methods from the oop map cache
3500 // so that obsolete methods are not pinned.
3501 the_class->oop_map_cache()->flush_obsolete_entries();
3502 }
3504 // increment the classRedefinedCount field in the_class and in any
3505 // direct and indirect subclasses of the_class
3506 increment_class_counter((InstanceKlass *)the_class(), THREAD);
3508 // RC_TRACE macro has an embedded ResourceMark
3509 RC_TRACE_WITH_THREAD(0x00000001, THREAD,
3510 ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
3511 the_class->external_name(),
3512 java_lang_Class::classRedefinedCount(the_class_mirror),
3513 os::available_memory() >> 10));
3515 RC_TIMER_STOP(_timer_rsc_phase2);
3516 } // end redefine_single_class()
3519 // Increment the classRedefinedCount field in the specific InstanceKlass
3520 // and in all direct and indirect subclasses.
3521 void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
3522 oop class_mirror = ik->java_mirror();
3523 Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
3524 int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
3525 java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
3527 if (class_oop != _the_class_oop) {
3528 // _the_class_oop count is printed at end of redefine_single_class()
3529 RC_TRACE_WITH_THREAD(0x00000008, THREAD,
3530 ("updated count in subclass=%s to %d", ik->external_name(), new_count));
3531 }
3533 for (Klass *subk = ik->subklass(); subk != NULL;
3534 subk = subk->next_sibling()) {
3535 if (subk->oop_is_instance()) {
3536 // Only update instanceKlasses
3537 InstanceKlass *subik = (InstanceKlass*)subk;
3538 // recursively do subclasses of the current subclass
3539 increment_class_counter(subik, THREAD);
3540 }
3541 }
3542 }
3544 void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
3545 bool no_old_methods = true; // be optimistic
3547 // Both array and instance classes have vtables.
3548 // a vtable should never contain old or obsolete methods
3549 ResourceMark rm(_thread);
3550 if (k->vtable_length() > 0 &&
3551 !k->vtable()->check_no_old_or_obsolete_entries()) {
3552 if (RC_TRACE_ENABLED(0x00004000)) {
3553 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3554 ("klassVtable::check_no_old_or_obsolete_entries failure"
3555 " -- OLD or OBSOLETE method found -- class: %s",
3556 k->signature_name()));
3557 k->vtable()->dump_vtable();
3558 }
3559 no_old_methods = false;
3560 }
3562 if (k->oop_is_instance()) {
3563 HandleMark hm(_thread);
3564 InstanceKlass *ik = InstanceKlass::cast(k);
3566 // an itable should never contain old or obsolete methods
3567 if (ik->itable_length() > 0 &&
3568 !ik->itable()->check_no_old_or_obsolete_entries()) {
3569 if (RC_TRACE_ENABLED(0x00004000)) {
3570 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3571 ("klassItable::check_no_old_or_obsolete_entries failure"
3572 " -- OLD or OBSOLETE method found -- class: %s",
3573 ik->signature_name()));
3574 ik->itable()->dump_itable();
3575 }
3576 no_old_methods = false;
3577 }
3579 // the constant pool cache should never contain old or obsolete methods
3580 if (ik->constants() != NULL &&
3581 ik->constants()->cache() != NULL &&
3582 !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
3583 if (RC_TRACE_ENABLED(0x00004000)) {
3584 RC_TRACE_WITH_THREAD(0x00004000, _thread,
3585 ("cp-cache::check_no_old_or_obsolete_entries failure"
3586 " -- OLD or OBSOLETE method found -- class: %s",
3587 ik->signature_name()));
3588 ik->constants()->cache()->dump_cache();
3589 }
3590 no_old_methods = false;
3591 }
3592 }
3594 // print and fail guarantee if old methods are found.
3595 if (!no_old_methods) {
3596 if (RC_TRACE_ENABLED(0x00004000)) {
3597 dump_methods();
3598 } else {
3599 tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
3600 "to see more info about the following guarantee() failure.");
3601 }
3602 guarantee(false, "OLD and/or OBSOLETE method(s) found");
3603 }
3604 }
3607 void VM_RedefineClasses::dump_methods() {
3608 int j;
3609 RC_TRACE(0x00004000, ("_old_methods --"));
3610 for (j = 0; j < _old_methods->length(); ++j) {
3611 Method* m = _old_methods->at(j);
3612 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3613 m->access_flags().print_on(tty);
3614 tty->print(" -- ");
3615 m->print_name(tty);
3616 tty->cr();
3617 }
3618 RC_TRACE(0x00004000, ("_new_methods --"));
3619 for (j = 0; j < _new_methods->length(); ++j) {
3620 Method* m = _new_methods->at(j);
3621 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3622 m->access_flags().print_on(tty);
3623 tty->print(" -- ");
3624 m->print_name(tty);
3625 tty->cr();
3626 }
3627 RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
3628 for (j = 0; j < _matching_methods_length; ++j) {
3629 Method* m = _matching_old_methods[j];
3630 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3631 m->access_flags().print_on(tty);
3632 tty->print(" -- ");
3633 m->print_name(tty);
3634 tty->cr();
3635 m = _matching_new_methods[j];
3636 RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
3637 m->access_flags().print_on(tty);
3638 tty->cr();
3639 }
3640 RC_TRACE(0x00004000, ("_deleted_methods --"));
3641 for (j = 0; j < _deleted_methods_length; ++j) {
3642 Method* m = _deleted_methods[j];
3643 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3644 m->access_flags().print_on(tty);
3645 tty->print(" -- ");
3646 m->print_name(tty);
3647 tty->cr();
3648 }
3649 RC_TRACE(0x00004000, ("_added_methods --"));
3650 for (j = 0; j < _added_methods_length; ++j) {
3651 Method* m = _added_methods[j];
3652 RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
3653 m->access_flags().print_on(tty);
3654 tty->print(" -- ");
3655 m->print_name(tty);
3656 tty->cr();
3657 }
3658 }