1 /*
2 * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/gcLocker.hpp"
27 #include "interpreter/bytecodes.hpp"
28 #include "interpreter/interpreter.hpp"
29 #include "interpreter/rewriter.hpp"
30 #include "memory/metaspaceShared.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/generateOopMap.hpp"
33 #include "prims/methodHandles.hpp"
34
35 // Computes a CPC map (new_index -> original_index) for constant pool entries
36 // that are referred to by the interpreter at runtime via the constant pool cache.
37 // Also computes a CP map (original_index -> new_index).
38 // Marks entries in CP which require additional processing.
39 void Rewriter::compute_index_maps() {
40 const int length = _pool->length();
41 init_maps(length);
42 bool saw_mh_symbol = false;
43 for (int i = 0; i < length; i++) {
44 int tag = _pool->tag_at(i).value();
45 switch (tag) {
46 case JVM_CONSTANT_InterfaceMethodref:
47 case JVM_CONSTANT_Fieldref : // fall through
48 case JVM_CONSTANT_Methodref : // fall through
49 add_cp_cache_entry(i);
50 break;
51 case JVM_CONSTANT_String:
52 case JVM_CONSTANT_MethodHandle : // fall through
53 case JVM_CONSTANT_MethodType : // fall through
54 add_resolved_references_entry(i);
55 break;
56 case JVM_CONSTANT_Utf8:
57 if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
58 _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
59 saw_mh_symbol = true;
60 }
61 break;
62 }
63 }
64
65 // Record limits of resolved reference map for constant pool cache indices
66 record_map_limits();
67
68 guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
69 "all cp cache indexes fit in a u2");
70
71 if (saw_mh_symbol) {
72 _method_handle_invokers.at_grow(length, 0);
73 }
74 }
75
76 // Unrewrite the bytecodes if an error occurs.
77 void Rewriter::restore_bytecodes() {
78 int len = _methods->length();
79 bool invokespecial_error = false;
80
81 for (int i = len-1; i >= 0; i--) {
82 Method* method = _methods->at(i);
83 scan_method(method, true, &invokespecial_error);
84 assert(!invokespecial_error, "reversing should not get an invokespecial error");
85 }
86 }
87
88 // Creates a constant pool cache given a CPC map
89 void Rewriter::make_constant_pool_cache(TRAPS) {
90 ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
91 ConstantPoolCache* cache =
92 ConstantPoolCache::allocate(loader_data, _cp_cache_map,
93 _invokedynamic_cp_cache_map,
94 _invokedynamic_references_map, CHECK);
95
96 // initialize object cache in constant pool
97 _pool->set_cache(cache);
98 cache->set_constant_pool(_pool());
99
100 // _resolved_references is stored in pool->cache(), so need to be done after
101 // the above lines.
102 _pool->initialize_resolved_references(loader_data, _resolved_references_map,
103 _resolved_reference_limit,
104 CHECK);
105 }
106
107
108
109 // The new finalization semantics says that registration of
110 // finalizable objects must be performed on successful return from the
111 // Object.<init> constructor. We could implement this trivially if
112 // <init> were never rewritten but since JVMTI allows this to occur, a
113 // more complicated solution is required. A special return bytecode
114 // is used only by Object.<init> to signal the finalization
115 // registration point. Additionally local 0 must be preserved so it's
116 // available to pass to the registration function. For simplicity we
117 // require that local 0 is never overwritten so it's available as an
118 // argument for registration.
119
120 void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) {
121 RawBytecodeStream bcs(method);
122 while (!bcs.is_last_bytecode()) {
123 Bytecodes::Code opcode = bcs.raw_next();
124 switch (opcode) {
125 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
126
127 case Bytecodes::_istore:
128 case Bytecodes::_lstore:
129 case Bytecodes::_fstore:
130 case Bytecodes::_dstore:
131 case Bytecodes::_astore:
132 if (bcs.get_index() != 0) continue;
133
134 // fall through
135 case Bytecodes::_istore_0:
136 case Bytecodes::_lstore_0:
137 case Bytecodes::_fstore_0:
138 case Bytecodes::_dstore_0:
139 case Bytecodes::_astore_0:
140 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
141 "can't overwrite local 0 in Object.<init>");
142 break;
143 }
144 }
145 }
146
147
148 // Rewrite a classfile-order CP index into a native-order CPC index.
149 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
150 address p = bcp + offset;
151 if (!reverse) {
152 int cp_index = Bytes::get_Java_u2(p);
153 int cache_index = cp_entry_to_cp_cache(cp_index);
154 Bytes::put_native_u2(p, cache_index);
155 if (!_method_handle_invokers.is_empty())
156 maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
157 } else {
158 int cache_index = Bytes::get_native_u2(p);
159 int pool_index = cp_cache_entry_pool_index(cache_index);
160 Bytes::put_Java_u2(p, pool_index);
161 if (!_method_handle_invokers.is_empty())
162 maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
163 }
164 }
165
166 // If the constant pool entry for invokespecial is InterfaceMethodref,
167 // we need to add a separate cpCache entry for its resolution, because it is
168 // different than the resolution for invokeinterface with InterfaceMethodref.
169 // These cannot share cpCache entries.
170 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
171 address p = bcp + offset;
172 if (!reverse) {
173 int cp_index = Bytes::get_Java_u2(p);
174 if (_pool->tag_at(cp_index).is_interface_method()) {
175 int cache_index = add_invokespecial_cp_cache_entry(cp_index);
176 if (cache_index != (int)(jushort) cache_index) {
177 *invokespecial_error = true;
178 }
179 Bytes::put_native_u2(p, cache_index);
180 } else {
181 rewrite_member_reference(bcp, offset, reverse);
182 }
183 } else {
184 rewrite_member_reference(bcp, offset, reverse);
185 }
186 }
187
188
189 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
190 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
191 if (!reverse) {
192 if ((*opc) == (u1)Bytecodes::_invokevirtual ||
193 // allow invokespecial as an alias, although it would be very odd:
194 (*opc) == (u1)Bytecodes::_invokespecial) {
195 assert(_pool->tag_at(cp_index).is_method(), "wrong index");
196 // Determine whether this is a signature-polymorphic method.
197 if (cp_index >= _method_handle_invokers.length()) return;
198 int status = _method_handle_invokers.at(cp_index);
199 assert(status >= -1 && status <= 1, "oob tri-state");
200 if (status == 0) {
201 if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
202 MethodHandles::is_signature_polymorphic_name(SystemDictionary::MethodHandle_klass(),
203 _pool->name_ref_at(cp_index))) {
204 // we may need a resolved_refs entry for the appendix
205 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
206 status = +1;
207 } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
208 MethodHandles::is_signature_polymorphic_name(SystemDictionary::VarHandle_klass(),
209 _pool->name_ref_at(cp_index))) {
210 // we may need a resolved_refs entry for the appendix
211 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
212 status = +1;
213 } else {
214 status = -1;
215 }
216 _method_handle_invokers.at(cp_index) = status;
217 }
218 // We use a special internal bytecode for such methods (if non-static).
219 // The basic reason for this is that such methods need an extra "appendix" argument
220 // to transmit the call site's intended call type.
221 if (status > 0) {
222 (*opc) = (u1)Bytecodes::_invokehandle;
223 }
224 }
225 } else {
226 // Do not need to look at cp_index.
227 if ((*opc) == (u1)Bytecodes::_invokehandle) {
228 (*opc) = (u1)Bytecodes::_invokevirtual;
229 // Ignore corner case of original _invokespecial instruction.
230 // This is safe because (a) the signature polymorphic method was final, and
231 // (b) the implementation of MethodHandle will not call invokespecial on it.
232 }
233 }
234 }
235
236
237 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
238 address p = bcp + offset;
239 assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
240 if (!reverse) {
241 int cp_index = Bytes::get_Java_u2(p);
242 int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
243 int resolved_index = add_invokedynamic_resolved_references_entries(cp_index, cache_index);
244 // Replace the trailing four bytes with a CPC index for the dynamic
245 // call site. Unlike other CPC entries, there is one per bytecode,
246 // not just one per distinct CP entry. In other words, the
247 // CPC-to-CP relation is many-to-one for invokedynamic entries.
248 // This means we must use a larger index size than u2 to address
249 // all these entries. That is the main reason invokedynamic
250 // must have a five-byte instruction format. (Of course, other JVM
251 // implementations can use the bytes for other purposes.)
252 // Note: We use native_u4 format exclusively for 4-byte indexes.
253 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
254 // add the bcp in case we need to patch this bytecode if we also find a
255 // invokespecial/InterfaceMethodref in the bytecode stream
256 _patch_invokedynamic_bcps->push(p);
257 _patch_invokedynamic_refs->push(resolved_index);
258 } else {
259 int cache_index = ConstantPool::decode_invokedynamic_index(
260 Bytes::get_native_u4(p));
261 // We will reverse the bytecode rewriting _after_ adjusting them.
262 // Adjust the cache index by offset to the invokedynamic entries in the
263 // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
264 int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
265 int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
266 assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
267 // zero out 4 bytes
268 Bytes::put_Java_u4(p, 0);
269 Bytes::put_Java_u2(p, cp_index);
270 }
271 }
272
273 void Rewriter::patch_invokedynamic_bytecodes() {
274 // If the end of the cp_cache is the same as after initializing with the
275 // cpool, nothing needs to be done. Invokedynamic bytecodes are at the
276 // correct offsets. ie. no invokespecials added
277 int delta = cp_cache_delta();
278 if (delta > 0) {
279 int length = _patch_invokedynamic_bcps->length();
280 assert(length == _patch_invokedynamic_refs->length(),
281 "lengths should match");
282 for (int i = 0; i < length; i++) {
283 address p = _patch_invokedynamic_bcps->at(i);
284 int cache_index = ConstantPool::decode_invokedynamic_index(
285 Bytes::get_native_u4(p));
286 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
287
288 // invokedynamic resolved references map also points to cp cache and must
289 // add delta to each.
290 int resolved_index = _patch_invokedynamic_refs->at(i);
291 for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
292 assert(_invokedynamic_references_map.at(resolved_index + entry) == cache_index,
293 "should be the same index");
294 _invokedynamic_references_map.at_put(resolved_index+entry,
295 cache_index + delta);
296 }
297 }
298 }
299 }
300
301
302 // Rewrite some ldc bytecodes to _fast_aldc
303 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
304 bool reverse) {
305 if (!reverse) {
306 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
307 address p = bcp + offset;
308 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
309 constantTag tag = _pool->tag_at(cp_index).value();
310 if (tag.is_method_handle() || tag.is_method_type() || tag.is_string()) {
311 int ref_index = cp_entry_to_resolved_references(cp_index);
312 if (is_wide) {
313 (*bcp) = Bytecodes::_fast_aldc_w;
314 assert(ref_index == (u2)ref_index, "index overflow");
315 Bytes::put_native_u2(p, ref_index);
316 } else {
317 (*bcp) = Bytecodes::_fast_aldc;
318 assert(ref_index == (u1)ref_index, "index overflow");
319 (*p) = (u1)ref_index;
320 }
321 }
322 } else {
323 Bytecodes::Code rewritten_bc =
324 (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
325 if ((*bcp) == rewritten_bc) {
326 address p = bcp + offset;
327 int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
328 int pool_index = resolved_references_entry_to_pool_index(ref_index);
329 if (is_wide) {
330 (*bcp) = Bytecodes::_ldc_w;
331 assert(pool_index == (u2)pool_index, "index overflow");
332 Bytes::put_Java_u2(p, pool_index);
333 } else {
334 (*bcp) = Bytecodes::_ldc;
335 assert(pool_index == (u1)pool_index, "index overflow");
336 (*p) = (u1)pool_index;
337 }
338 }
339 }
340 }
341
342
343 // Rewrites a method given the index_map information
344 void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_error) {
345
346 int nof_jsrs = 0;
347 bool has_monitor_bytecodes = false;
348
349 {
350 // We cannot tolerate a GC in this block, because we've
351 // cached the bytecodes in 'code_base'. If the Method*
352 // moves, the bytecodes will also move.
353 NoSafepointVerifier nsv;
354 Bytecodes::Code c;
355
356 // Bytecodes and their length
357 const address code_base = method->code_base();
358 const int code_length = method->code_size();
359
360 int bc_length;
361 for (int bci = 0; bci < code_length; bci += bc_length) {
362 address bcp = code_base + bci;
363 int prefix_length = 0;
364 c = (Bytecodes::Code)(*bcp);
365
366 // Since we have the code, see if we can get the length
367 // directly. Some more complicated bytecodes will report
368 // a length of zero, meaning we need to make another method
369 // call to calculate the length.
370 bc_length = Bytecodes::length_for(c);
371 if (bc_length == 0) {
372 bc_length = Bytecodes::length_at(method, bcp);
373
374 // length_at will put us at the bytecode after the one modified
375 // by 'wide'. We don't currently examine any of the bytecodes
376 // modified by wide, but in case we do in the future...
377 if (c == Bytecodes::_wide) {
378 prefix_length = 1;
379 c = (Bytecodes::Code)bcp[1];
380 }
381 }
382
383 assert(bc_length != 0, "impossible bytecode length");
384
385 switch (c) {
386 case Bytecodes::_lookupswitch : {
387 #ifndef CC_INTERP
388 Bytecode_lookupswitch bc(method, bcp);
389 (*bcp) = (
390 bc.number_of_pairs() < BinarySwitchThreshold
391 ? Bytecodes::_fast_linearswitch
392 : Bytecodes::_fast_binaryswitch
393 );
394 #endif
395 break;
396 }
397 case Bytecodes::_fast_linearswitch:
398 case Bytecodes::_fast_binaryswitch: {
399 #ifndef CC_INTERP
400 (*bcp) = Bytecodes::_lookupswitch;
401 #endif
402 break;
403 }
404
405 case Bytecodes::_invokespecial : {
406 rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
407 break;
408 }
409
410 case Bytecodes::_putstatic :
411 case Bytecodes::_putfield : {
412 if (!reverse) {
413 // Check if any final field of the class given as parameter is modified
414 // outside of initializer methods of the class. Fields that are modified
415 // are marked with a flag. For marked fields, the compilers do not perform
416 // constant folding (as the field can be changed after initialization).
417 //
418 // The check is performed after verification and only if verification has
419 // succeeded. Therefore, the class is guaranteed to be well-formed.
420 InstanceKlass* klass = method->method_holder();
421 u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
422 constantPoolHandle cp(method->constants());
423 Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
424
425 if (klass->name() == ref_class_name) {
426 Symbol* field_name = cp->name_ref_at(bc_index);
427 Symbol* field_sig = cp->signature_ref_at(bc_index);
428
429 fieldDescriptor fd;
430 if (klass->find_field(field_name, field_sig, &fd) != NULL) {
431 if (fd.access_flags().is_final()) {
432 if (fd.access_flags().is_static()) {
433 if (!method->is_static_initializer()) {
434 fd.set_has_initialized_final_update(true);
435 }
436 } else {
437 if (!method->is_object_initializer()) {
438 fd.set_has_initialized_final_update(true);
439 }
440 }
441 }
442 }
443 }
444 }
445 }
446 // fall through
447 case Bytecodes::_getstatic : // fall through
448 case Bytecodes::_getfield : // fall through
449 case Bytecodes::_invokevirtual : // fall through
450 case Bytecodes::_invokestatic :
451 case Bytecodes::_invokeinterface:
452 case Bytecodes::_invokehandle : // if reverse=true
453 rewrite_member_reference(bcp, prefix_length+1, reverse);
454 break;
455 case Bytecodes::_invokedynamic:
456 rewrite_invokedynamic(bcp, prefix_length+1, reverse);
457 break;
458 case Bytecodes::_ldc:
459 case Bytecodes::_fast_aldc: // if reverse=true
460 maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
461 break;
462 case Bytecodes::_ldc_w:
463 case Bytecodes::_fast_aldc_w: // if reverse=true
464 maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
465 break;
466 case Bytecodes::_jsr : // fall through
467 case Bytecodes::_jsr_w : nof_jsrs++; break;
468 case Bytecodes::_monitorenter : // fall through
469 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break;
470 }
471 }
472 }
473
474 // Update access flags
475 if (has_monitor_bytecodes) {
476 method->set_has_monitor_bytecodes();
477 }
478
479 // The present of a jsr bytecode implies that the method might potentially
480 // have to be rewritten, so we run the oopMapGenerator on the method
481 if (nof_jsrs > 0) {
482 method->set_has_jsrs();
483 // Second pass will revisit this method.
484 assert(method->has_jsrs(), "didn't we just set this?");
485 }
486 }
487
488 // After constant pool is created, revisit methods containing jsrs.
489 methodHandle Rewriter::rewrite_jsrs(methodHandle method, TRAPS) {
490 ResourceMark rm(THREAD);
491 ResolveOopMapConflicts romc(method);
492 methodHandle original_method = method;
493 method = romc.do_potential_rewrite(CHECK_(methodHandle()));
494 // Update monitor matching info.
495 if (romc.monitor_safe()) {
496 method->set_guaranteed_monitor_matching();
497 }
498
499 return method;
500 }
501
502 void Rewriter::rewrite_bytecodes(TRAPS) {
503 assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
504
505 // determine index maps for Method* rewriting
506 compute_index_maps();
507
508 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
509 bool did_rewrite = false;
510 int i = _methods->length();
511 while (i-- > 0) {
512 Method* method = _methods->at(i);
513 if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
514 // rewrite the return bytecodes of Object.<init> to register the
515 // object for finalization if needed.
516 methodHandle m(THREAD, method);
517 rewrite_Object_init(m, CHECK);
518 did_rewrite = true;
519 break;
520 }
521 }
522 assert(did_rewrite, "must find Object::<init> to rewrite it");
523 }
524
525 // rewrite methods, in two passes
526 int len = _methods->length();
527 bool invokespecial_error = false;
528
529 for (int i = len-1; i >= 0; i--) {
530 Method* method = _methods->at(i);
531 scan_method(method, false, &invokespecial_error);
532 if (invokespecial_error) {
533 // If you get an error here, there is no reversing bytecodes
534 // This exception is stored for this class and no further attempt is
535 // made at verifying or rewriting.
536 THROW_MSG(vmSymbols::java_lang_InternalError(),
537 "This classfile overflows invokespecial for interfaces "
538 "and cannot be loaded");
539 return;
540 }
541 }
542
543 // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
544 // entries had to be added.
545 patch_invokedynamic_bytecodes();
546 }
547
548 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) {
549 if (!DumpSharedSpaces) {
550 assert(!MetaspaceShared::is_in_shared_space(klass), "archive methods must not be rewritten at run time");
551 }
552 ResourceMark rm(THREAD);
553 Rewriter rw(klass, klass->constants(), klass->methods(), CHECK);
554 // (That's all, folks.)
555 }
556
557 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
558 : _klass(klass),
559 _pool(cpool),
560 _methods(methods),
561 _cp_map(cpool->length()),
562 _cp_cache_map(cpool->length() / 2),
563 _reference_map(cpool->length()),
564 _resolved_references_map(cpool->length() / 2),
565 _invokedynamic_references_map(cpool->length() / 2),
566 _method_handle_invokers(cpool->length()),
567 _invokedynamic_cp_cache_map(cpool->length() / 4)
568 {
569
570 // Rewrite bytecodes - exception here exits.
571 rewrite_bytecodes(CHECK);
572
573 // Stress restoring bytecodes
574 if (StressRewriter) {
575 restore_bytecodes();
576 rewrite_bytecodes(CHECK);
577 }
578
579 // allocate constant pool cache, now that we've seen all the bytecodes
580 make_constant_pool_cache(THREAD);
581
582 // Restore bytecodes to their unrewritten state if there are exceptions
583 // rewriting bytecodes or allocating the cpCache
584 if (HAS_PENDING_EXCEPTION) {
585 restore_bytecodes();
586 return;
587 }
588
589 // Relocate after everything, but still do this under the is_rewritten flag,
590 // so methods with jsrs in custom class lists in aren't attempted to be
591 // rewritten in the RO section of the shared archive.
592 // Relocated bytecodes don't have to be restored, only the cp cache entries
593 int len = _methods->length();
594 for (int i = len-1; i >= 0; i--) {
595 methodHandle m(THREAD, _methods->at(i));
596
597 if (m->has_jsrs()) {
598 m = rewrite_jsrs(m, THREAD);
599 // Restore bytecodes to their unrewritten state if there are exceptions
600 // relocating bytecodes. If some are relocated, that is ok because that
601 // doesn't affect constant pool to cpCache rewriting.
602 if (HAS_PENDING_EXCEPTION) {
603 restore_bytecodes();
604 return;
605 }
606 // Method might have gotten rewritten.
607 methods->at_put(i, m());
608 }
609 }
610 }