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/metadataFactory.hpp"
31 #include "memory/metaspaceShared.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/generateOopMap.hpp"
34 #include "prims/methodHandles.hpp"
35
36 // Computes a CPC map (new_index -> original_index) for constant pool entries
37 // that are referred to by the interpreter at runtime via the constant pool cache.
38 // Also computes a CP map (original_index -> new_index).
39 // Marks entries in CP which require additional processing.
40 void Rewriter::compute_index_maps() {
41 const int length = _pool->length();
42 init_maps(length);
43 bool saw_mh_symbol = false;
44 for (int i = 0; i < length; i++) {
45 int tag = _pool->tag_at(i).value();
46 switch (tag) {
47 case JVM_CONSTANT_InterfaceMethodref:
48 case JVM_CONSTANT_Fieldref : // fall through
49 case JVM_CONSTANT_Methodref : // fall through
50 add_cp_cache_entry(i);
51 break;
52 case JVM_CONSTANT_String:
53 case JVM_CONSTANT_MethodHandle : // fall through
54 case JVM_CONSTANT_MethodType : // fall through
55 add_resolved_references_entry(i);
56 break;
57 case JVM_CONSTANT_Utf8:
58 if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
59 _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
60 saw_mh_symbol = true;
61 }
62 break;
63 }
64 }
65
66 // Record limits of resolved reference map for constant pool cache indices
67 record_map_limits();
68
69 guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
70 "all cp cache indexes fit in a u2");
71
72 if (saw_mh_symbol) {
73 _method_handle_invokers.at_grow(length, 0);
74 }
75 }
76
77 // Unrewrite the bytecodes if an error occurs.
78 void Rewriter::restore_bytecodes() {
79 int len = _methods->length();
80 bool invokespecial_error = false;
81
82 for (int i = len-1; i >= 0; i--) {
83 Method* method = _methods->at(i);
84 scan_method(method, true, &invokespecial_error);
85 assert(!invokespecial_error, "reversing should not get an invokespecial error");
86 }
87 }
88
89 // Creates a constant pool cache given a CPC map
90 void Rewriter::make_constant_pool_cache(TRAPS) {
91 ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
92 ConstantPoolCache* cache =
93 ConstantPoolCache::allocate(loader_data, _cp_cache_map,
94 _invokedynamic_cp_cache_map,
95 _invokedynamic_references_map, CHECK);
96
97 // initialize object cache in constant pool
98 _pool->set_cache(cache);
99 cache->set_constant_pool(_pool());
100
101 // _resolved_references is stored in pool->cache(), so need to be done after
102 // the above lines.
103 _pool->initialize_resolved_references(loader_data, _resolved_references_map,
104 _resolved_reference_limit,
105 THREAD);
106
107 // Clean up constant pool cache if initialize_resolved_references() failed.
108 if (HAS_PENDING_EXCEPTION) {
109 MetadataFactory::free_metadata(loader_data, cache);
110 _pool->set_cache(NULL); // so the verifier isn't confused
111 }
112
113 DEBUG_ONLY(
114 if (DumpSharedSpaces) {
115 cache->verify_just_initialized();
116 })
117 }
118
119
120
121 // The new finalization semantics says that registration of
122 // finalizable objects must be performed on successful return from the
123 // Object.<init> constructor. We could implement this trivially if
124 // <init> were never rewritten but since JVMTI allows this to occur, a
125 // more complicated solution is required. A special return bytecode
126 // is used only by Object.<init> to signal the finalization
127 // registration point. Additionally local 0 must be preserved so it's
128 // available to pass to the registration function. For simplicity we
129 // require that local 0 is never overwritten so it's available as an
130 // argument for registration.
131
132 void Rewriter::rewrite_Object_init(const methodHandle& method, TRAPS) {
133 RawBytecodeStream bcs(method);
134 while (!bcs.is_last_bytecode()) {
135 Bytecodes::Code opcode = bcs.raw_next();
136 switch (opcode) {
137 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
138
139 case Bytecodes::_istore:
140 case Bytecodes::_lstore:
141 case Bytecodes::_fstore:
142 case Bytecodes::_dstore:
143 case Bytecodes::_astore:
144 if (bcs.get_index() != 0) continue;
145
146 // fall through
147 case Bytecodes::_istore_0:
148 case Bytecodes::_lstore_0:
149 case Bytecodes::_fstore_0:
150 case Bytecodes::_dstore_0:
151 case Bytecodes::_astore_0:
152 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
153 "can't overwrite local 0 in Object.<init>");
154 break;
155
156 default:
157 break;
158 }
159 }
160 }
161
162
163 // Rewrite a classfile-order CP index into a native-order CPC index.
164 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
165 address p = bcp + offset;
166 if (!reverse) {
167 int cp_index = Bytes::get_Java_u2(p);
168 int cache_index = cp_entry_to_cp_cache(cp_index);
169 Bytes::put_native_u2(p, cache_index);
170 if (!_method_handle_invokers.is_empty())
171 maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
172 } else {
173 int cache_index = Bytes::get_native_u2(p);
174 int pool_index = cp_cache_entry_pool_index(cache_index);
175 Bytes::put_Java_u2(p, pool_index);
176 if (!_method_handle_invokers.is_empty())
177 maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
178 }
179 }
180
181 // If the constant pool entry for invokespecial is InterfaceMethodref,
182 // we need to add a separate cpCache entry for its resolution, because it is
183 // different than the resolution for invokeinterface with InterfaceMethodref.
184 // These cannot share cpCache entries.
185 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
186 address p = bcp + offset;
187 if (!reverse) {
188 int cp_index = Bytes::get_Java_u2(p);
189 if (_pool->tag_at(cp_index).is_interface_method()) {
190 int cache_index = add_invokespecial_cp_cache_entry(cp_index);
191 if (cache_index != (int)(jushort) cache_index) {
192 *invokespecial_error = true;
193 }
194 Bytes::put_native_u2(p, cache_index);
195 } else {
196 rewrite_member_reference(bcp, offset, reverse);
197 }
198 } else {
199 rewrite_member_reference(bcp, offset, reverse);
200 }
201 }
202
203
204 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
205 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
206 if (!reverse) {
207 if ((*opc) == (u1)Bytecodes::_invokevirtual ||
208 // allow invokespecial as an alias, although it would be very odd:
209 (*opc) == (u1)Bytecodes::_invokespecial) {
210 assert(_pool->tag_at(cp_index).is_method(), "wrong index");
211 // Determine whether this is a signature-polymorphic method.
212 if (cp_index >= _method_handle_invokers.length()) return;
213 int status = _method_handle_invokers.at(cp_index);
214 assert(status >= -1 && status <= 1, "oob tri-state");
215 if (status == 0) {
216 if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
217 MethodHandles::is_signature_polymorphic_name(SystemDictionary::MethodHandle_klass(),
218 _pool->name_ref_at(cp_index))) {
219 // we may need a resolved_refs entry for the appendix
220 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
221 status = +1;
222 } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
223 MethodHandles::is_signature_polymorphic_name(SystemDictionary::VarHandle_klass(),
224 _pool->name_ref_at(cp_index))) {
225 // we may need a resolved_refs entry for the appendix
226 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
227 status = +1;
228 } else {
229 status = -1;
230 }
231 _method_handle_invokers.at(cp_index) = status;
232 }
233 // We use a special internal bytecode for such methods (if non-static).
234 // The basic reason for this is that such methods need an extra "appendix" argument
235 // to transmit the call site's intended call type.
236 if (status > 0) {
237 (*opc) = (u1)Bytecodes::_invokehandle;
238 }
239 }
240 } else {
241 // Do not need to look at cp_index.
242 if ((*opc) == (u1)Bytecodes::_invokehandle) {
243 (*opc) = (u1)Bytecodes::_invokevirtual;
244 // Ignore corner case of original _invokespecial instruction.
245 // This is safe because (a) the signature polymorphic method was final, and
246 // (b) the implementation of MethodHandle will not call invokespecial on it.
247 }
248 }
249 }
250
251
252 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
253 address p = bcp + offset;
254 assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
255 if (!reverse) {
256 int cp_index = Bytes::get_Java_u2(p);
257 int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
258 int resolved_index = add_invokedynamic_resolved_references_entries(cp_index, cache_index);
259 // Replace the trailing four bytes with a CPC index for the dynamic
260 // call site. Unlike other CPC entries, there is one per bytecode,
261 // not just one per distinct CP entry. In other words, the
262 // CPC-to-CP relation is many-to-one for invokedynamic entries.
263 // This means we must use a larger index size than u2 to address
264 // all these entries. That is the main reason invokedynamic
265 // must have a five-byte instruction format. (Of course, other JVM
266 // implementations can use the bytes for other purposes.)
267 // Note: We use native_u4 format exclusively for 4-byte indexes.
268 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
269 // add the bcp in case we need to patch this bytecode if we also find a
270 // invokespecial/InterfaceMethodref in the bytecode stream
271 _patch_invokedynamic_bcps->push(p);
272 _patch_invokedynamic_refs->push(resolved_index);
273 } else {
274 int cache_index = ConstantPool::decode_invokedynamic_index(
275 Bytes::get_native_u4(p));
276 // We will reverse the bytecode rewriting _after_ adjusting them.
277 // Adjust the cache index by offset to the invokedynamic entries in the
278 // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
279 int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
280 int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
281 assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
282 // zero out 4 bytes
283 Bytes::put_Java_u4(p, 0);
284 Bytes::put_Java_u2(p, cp_index);
285 }
286 }
287
288 void Rewriter::patch_invokedynamic_bytecodes() {
289 // If the end of the cp_cache is the same as after initializing with the
290 // cpool, nothing needs to be done. Invokedynamic bytecodes are at the
291 // correct offsets. ie. no invokespecials added
292 int delta = cp_cache_delta();
293 if (delta > 0) {
294 int length = _patch_invokedynamic_bcps->length();
295 assert(length == _patch_invokedynamic_refs->length(),
296 "lengths should match");
297 for (int i = 0; i < length; i++) {
298 address p = _patch_invokedynamic_bcps->at(i);
299 int cache_index = ConstantPool::decode_invokedynamic_index(
300 Bytes::get_native_u4(p));
301 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
302
303 // invokedynamic resolved references map also points to cp cache and must
304 // add delta to each.
305 int resolved_index = _patch_invokedynamic_refs->at(i);
306 for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
307 assert(_invokedynamic_references_map.at(resolved_index + entry) == cache_index,
308 "should be the same index");
309 _invokedynamic_references_map.at_put(resolved_index+entry,
310 cache_index + delta);
311 }
312 }
313 }
314 }
315
316
317 // Rewrite some ldc bytecodes to _fast_aldc
318 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
319 bool reverse) {
320 if (!reverse) {
321 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
322 address p = bcp + offset;
323 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
324 constantTag tag = _pool->tag_at(cp_index).value();
325 if (tag.is_method_handle() || tag.is_method_type() || tag.is_string()) {
326 int ref_index = cp_entry_to_resolved_references(cp_index);
327 if (is_wide) {
328 (*bcp) = Bytecodes::_fast_aldc_w;
329 assert(ref_index == (u2)ref_index, "index overflow");
330 Bytes::put_native_u2(p, ref_index);
331 } else {
332 (*bcp) = Bytecodes::_fast_aldc;
333 assert(ref_index == (u1)ref_index, "index overflow");
334 (*p) = (u1)ref_index;
335 }
336 }
337 } else {
338 Bytecodes::Code rewritten_bc =
339 (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
340 if ((*bcp) == rewritten_bc) {
341 address p = bcp + offset;
342 int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
343 int pool_index = resolved_references_entry_to_pool_index(ref_index);
344 if (is_wide) {
345 (*bcp) = Bytecodes::_ldc_w;
346 assert(pool_index == (u2)pool_index, "index overflow");
347 Bytes::put_Java_u2(p, pool_index);
348 } else {
349 (*bcp) = Bytecodes::_ldc;
350 assert(pool_index == (u1)pool_index, "index overflow");
351 (*p) = (u1)pool_index;
352 }
353 }
354 }
355 }
356
357
358 // Rewrites a method given the index_map information
359 void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_error) {
360
361 int nof_jsrs = 0;
362 bool has_monitor_bytecodes = false;
363 Bytecodes::Code c;
364
365 // Bytecodes and their length
366 const address code_base = method->code_base();
367 const int code_length = method->code_size();
368
369 int bc_length;
370 for (int bci = 0; bci < code_length; bci += bc_length) {
371 address bcp = code_base + bci;
372 int prefix_length = 0;
373 c = (Bytecodes::Code)(*bcp);
374
375 // Since we have the code, see if we can get the length
376 // directly. Some more complicated bytecodes will report
377 // a length of zero, meaning we need to make another method
378 // call to calculate the length.
379 bc_length = Bytecodes::length_for(c);
380 if (bc_length == 0) {
381 bc_length = Bytecodes::length_at(method, bcp);
382
383 // length_at will put us at the bytecode after the one modified
384 // by 'wide'. We don't currently examine any of the bytecodes
385 // modified by wide, but in case we do in the future...
386 if (c == Bytecodes::_wide) {
387 prefix_length = 1;
388 c = (Bytecodes::Code)bcp[1];
389 }
390 }
391
392 assert(bc_length != 0, "impossible bytecode length");
393
394 switch (c) {
395 case Bytecodes::_lookupswitch : {
396 #ifndef CC_INTERP
397 Bytecode_lookupswitch bc(method, bcp);
398 (*bcp) = (
399 bc.number_of_pairs() < BinarySwitchThreshold
400 ? Bytecodes::_fast_linearswitch
401 : Bytecodes::_fast_binaryswitch
402 );
403 #endif
404 break;
405 }
406 case Bytecodes::_fast_linearswitch:
407 case Bytecodes::_fast_binaryswitch: {
408 #ifndef CC_INTERP
409 (*bcp) = Bytecodes::_lookupswitch;
410 #endif
411 break;
412 }
413
414 case Bytecodes::_invokespecial : {
415 rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
416 break;
417 }
418
419 case Bytecodes::_putstatic :
420 case Bytecodes::_putfield : {
421 if (!reverse) {
422 // Check if any final field of the class given as parameter is modified
423 // outside of initializer methods of the class. Fields that are modified
424 // are marked with a flag. For marked fields, the compilers do not perform
425 // constant folding (as the field can be changed after initialization).
426 //
427 // The check is performed after verification and only if verification has
428 // succeeded. Therefore, the class is guaranteed to be well-formed.
429 InstanceKlass* klass = method->method_holder();
430 u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
431 constantPoolHandle cp(method->constants());
432 Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
433
434 if (klass->name() == ref_class_name) {
435 Symbol* field_name = cp->name_ref_at(bc_index);
436 Symbol* field_sig = cp->signature_ref_at(bc_index);
437
438 fieldDescriptor fd;
439 if (klass->find_field(field_name, field_sig, &fd) != NULL) {
440 if (fd.access_flags().is_final()) {
441 if (fd.access_flags().is_static()) {
442 if (!method->is_static_initializer()) {
443 fd.set_has_initialized_final_update(true);
444 }
445 } else {
446 if (!method->is_object_initializer()) {
447 fd.set_has_initialized_final_update(true);
448 }
449 }
450 }
451 }
452 }
453 }
454 }
455 // fall through
456 case Bytecodes::_getstatic : // fall through
457 case Bytecodes::_getfield : // fall through
458 case Bytecodes::_invokevirtual : // fall through
459 case Bytecodes::_invokestatic :
460 case Bytecodes::_invokeinterface:
461 case Bytecodes::_invokehandle : // if reverse=true
462 rewrite_member_reference(bcp, prefix_length+1, reverse);
463 break;
464 case Bytecodes::_invokedynamic:
465 rewrite_invokedynamic(bcp, prefix_length+1, reverse);
466 break;
467 case Bytecodes::_ldc:
468 case Bytecodes::_fast_aldc: // if reverse=true
469 maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
470 break;
471 case Bytecodes::_ldc_w:
472 case Bytecodes::_fast_aldc_w: // if reverse=true
473 maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
474 break;
475 case Bytecodes::_jsr : // fall through
476 case Bytecodes::_jsr_w : nof_jsrs++; break;
477 case Bytecodes::_monitorenter : // fall through
478 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break;
479
480 default: break;
481 }
482 }
483
484 // Update access flags
485 if (has_monitor_bytecodes) {
486 method->set_has_monitor_bytecodes();
487 }
488
489 // The present of a jsr bytecode implies that the method might potentially
490 // have to be rewritten, so we run the oopMapGenerator on the method
491 if (nof_jsrs > 0) {
492 method->set_has_jsrs();
493 // Second pass will revisit this method.
494 assert(method->has_jsrs(), "didn't we just set this?");
495 }
496 }
497
498 // After constant pool is created, revisit methods containing jsrs.
499 methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) {
500 ResourceMark rm(THREAD);
501 ResolveOopMapConflicts romc(method);
502 methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle()));
503 // Update monitor matching info.
504 if (romc.monitor_safe()) {
505 new_method->set_guaranteed_monitor_matching();
506 }
507
508 return new_method;
509 }
510
511 void Rewriter::rewrite_bytecodes(TRAPS) {
512 assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
513
514 // determine index maps for Method* rewriting
515 compute_index_maps();
516
517 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
518 bool did_rewrite = false;
519 int i = _methods->length();
520 while (i-- > 0) {
521 Method* method = _methods->at(i);
522 if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
523 // rewrite the return bytecodes of Object.<init> to register the
524 // object for finalization if needed.
525 methodHandle m(THREAD, method);
526 rewrite_Object_init(m, CHECK);
527 did_rewrite = true;
528 break;
529 }
530 }
531 assert(did_rewrite, "must find Object::<init> to rewrite it");
532 }
533
534 // rewrite methods, in two passes
535 int len = _methods->length();
536 bool invokespecial_error = false;
537
538 for (int i = len-1; i >= 0; i--) {
539 Method* method = _methods->at(i);
540 scan_method(method, false, &invokespecial_error);
541 if (invokespecial_error) {
542 // If you get an error here, there is no reversing bytecodes
543 // This exception is stored for this class and no further attempt is
544 // made at verifying or rewriting.
545 THROW_MSG(vmSymbols::java_lang_InternalError(),
546 "This classfile overflows invokespecial for interfaces "
547 "and cannot be loaded");
548 return;
549 }
550 }
551
552 // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
553 // entries had to be added.
554 patch_invokedynamic_bytecodes();
555 }
556
557 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) {
558 if (!DumpSharedSpaces) {
559 assert(!MetaspaceShared::is_in_shared_space(klass), "archive methods must not be rewritten at run time");
560 }
561 ResourceMark rm(THREAD);
562 Rewriter rw(klass, klass->constants(), klass->methods(), CHECK);
563 // (That's all, folks.)
564 }
565
566 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
567 : _klass(klass),
568 _pool(cpool),
569 _methods(methods),
570 _cp_map(cpool->length()),
571 _cp_cache_map(cpool->length() / 2),
572 _reference_map(cpool->length()),
573 _resolved_references_map(cpool->length() / 2),
574 _invokedynamic_references_map(cpool->length() / 2),
575 _method_handle_invokers(cpool->length()),
576 _invokedynamic_cp_cache_map(cpool->length() / 4)
577 {
578
579 // Rewrite bytecodes - exception here exits.
580 rewrite_bytecodes(CHECK);
581
582 // Stress restoring bytecodes
583 if (StressRewriter) {
584 restore_bytecodes();
585 rewrite_bytecodes(CHECK);
586 }
587
588 // allocate constant pool cache, now that we've seen all the bytecodes
589 make_constant_pool_cache(THREAD);
590
591 // Restore bytecodes to their unrewritten state if there are exceptions
592 // rewriting bytecodes or allocating the cpCache
593 if (HAS_PENDING_EXCEPTION) {
594 restore_bytecodes();
595 return;
596 }
597
598 // Relocate after everything, but still do this under the is_rewritten flag,
599 // so methods with jsrs in custom class lists in aren't attempted to be
600 // rewritten in the RO section of the shared archive.
601 // Relocated bytecodes don't have to be restored, only the cp cache entries
602 int len = _methods->length();
603 for (int i = len-1; i >= 0; i--) {
604 methodHandle m(THREAD, _methods->at(i));
605
606 if (m->has_jsrs()) {
607 m = rewrite_jsrs(m, THREAD);
608 // Restore bytecodes to their unrewritten state if there are exceptions
609 // relocating bytecodes. If some are relocated, that is ok because that
610 // doesn't affect constant pool to cpCache rewriting.
611 if (HAS_PENDING_EXCEPTION) {
612 restore_bytecodes();
613 return;
614 }
615 // Method might have gotten rewritten.
616 methods->at_put(i, m());
617 }
618 }
619 }