1 /*
2 * Copyright (c) 1998, 2018, 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/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_Dynamic:
52 assert(_pool->has_dynamic_constant(), "constant pool's _has_dynamic_constant flag not set");
53 add_resolved_references_entry(i);
54 break;
55 case JVM_CONSTANT_String : // fall through
56 case JVM_CONSTANT_MethodHandle : // fall through
57 case JVM_CONSTANT_MethodType : // fall through
58 add_resolved_references_entry(i);
59 break;
60 case JVM_CONSTANT_Utf8:
61 if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
62 _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
63 saw_mh_symbol = true;
64 }
65 break;
66 }
67 }
68
69 // Record limits of resolved reference map for constant pool cache indices
70 record_map_limits();
71
72 guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
73 "all cp cache indexes fit in a u2");
74
75 if (saw_mh_symbol) {
76 _method_handle_invokers.at_grow(length, 0);
77 }
78 }
79
80 // Unrewrite the bytecodes if an error occurs.
81 void Rewriter::restore_bytecodes() {
82 int len = _methods->length();
83 bool invokespecial_error = false;
84
85 for (int i = len-1; i >= 0; i--) {
86 Method* method = _methods->at(i);
87 scan_method(method, true, &invokespecial_error);
88 assert(!invokespecial_error, "reversing should not get an invokespecial error");
89 }
90 }
91
92 // Creates a constant pool cache given a CPC map
93 void Rewriter::make_constant_pool_cache(TRAPS) {
94 ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
95 ConstantPoolCache* cache =
96 ConstantPoolCache::allocate(loader_data, _cp_cache_map,
97 _invokedynamic_cp_cache_map,
98 _invokedynamic_references_map, CHECK);
99
100 // initialize object cache in constant pool
101 _pool->set_cache(cache);
102 cache->set_constant_pool(_pool());
103
104 // _resolved_references is stored in pool->cache(), so need to be done after
105 // the above lines.
106 _pool->initialize_resolved_references(loader_data, _resolved_references_map,
107 _resolved_reference_limit,
108 THREAD);
109
110 // Clean up constant pool cache if initialize_resolved_references() failed.
111 if (HAS_PENDING_EXCEPTION) {
112 MetadataFactory::free_metadata(loader_data, cache);
113 _pool->set_cache(NULL); // so the verifier isn't confused
114 }
115
116 DEBUG_ONLY(
117 if (DumpSharedSpaces) {
118 cache->verify_just_initialized();
119 })
120 }
121
122
123
124 // The new finalization semantics says that registration of
125 // finalizable objects must be performed on successful return from the
126 // Object.<init> constructor. We could implement this trivially if
127 // <init> were never rewritten but since JVMTI allows this to occur, a
128 // more complicated solution is required. A special return bytecode
129 // is used only by Object.<init> to signal the finalization
130 // registration point. Additionally local 0 must be preserved so it's
131 // available to pass to the registration function. For simplicity we
132 // require that local 0 is never overwritten so it's available as an
133 // argument for registration.
134
135 void Rewriter::rewrite_Object_init(const methodHandle& method, TRAPS) {
136 RawBytecodeStream bcs(method);
137 while (!bcs.is_last_bytecode()) {
138 Bytecodes::Code opcode = bcs.raw_next();
139 switch (opcode) {
140 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
141
142 case Bytecodes::_istore:
143 case Bytecodes::_lstore:
144 case Bytecodes::_fstore:
145 case Bytecodes::_dstore:
146 case Bytecodes::_astore:
147 if (bcs.get_index() != 0) continue;
148
149 // fall through
150 case Bytecodes::_istore_0:
151 case Bytecodes::_lstore_0:
152 case Bytecodes::_fstore_0:
153 case Bytecodes::_dstore_0:
154 case Bytecodes::_astore_0:
155 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
156 "can't overwrite local 0 in Object.<init>");
157 break;
158
159 default:
160 break;
161 }
162 }
163 }
164
165
166 // Rewrite a classfile-order CP index into a native-order CPC index.
167 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
168 address p = bcp + offset;
169 if (!reverse) {
170 int cp_index = Bytes::get_Java_u2(p);
171 int cache_index = cp_entry_to_cp_cache(cp_index);
172 Bytes::put_native_u2(p, cache_index);
173 if (!_method_handle_invokers.is_empty())
174 maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
175 } else {
176 int cache_index = Bytes::get_native_u2(p);
177 int pool_index = cp_cache_entry_pool_index(cache_index);
178 Bytes::put_Java_u2(p, pool_index);
179 if (!_method_handle_invokers.is_empty())
180 maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
181 }
182 }
183
184 // If the constant pool entry for invokespecial is InterfaceMethodref,
185 // we need to add a separate cpCache entry for its resolution, because it is
186 // different than the resolution for invokeinterface with InterfaceMethodref.
187 // These cannot share cpCache entries.
188 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
189 address p = bcp + offset;
190 if (!reverse) {
191 int cp_index = Bytes::get_Java_u2(p);
192 if (_pool->tag_at(cp_index).is_interface_method()) {
193 int cache_index = add_invokespecial_cp_cache_entry(cp_index);
194 if (cache_index != (int)(jushort) cache_index) {
195 *invokespecial_error = true;
196 }
197 Bytes::put_native_u2(p, cache_index);
198 } else {
199 rewrite_member_reference(bcp, offset, reverse);
200 }
201 } else {
202 rewrite_member_reference(bcp, offset, reverse);
203 }
204 }
205
206 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
207 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
208 if (!reverse) {
209 if ((*opc) == (u1)Bytecodes::_invokevirtual ||
210 // allow invokespecial as an alias, although it would be very odd:
211 (*opc) == (u1)Bytecodes::_invokespecial) {
212 assert(_pool->tag_at(cp_index).is_method(), "wrong index");
213 // Determine whether this is a signature-polymorphic method.
214 if (cp_index >= _method_handle_invokers.length()) return;
215 int status = _method_handle_invokers.at(cp_index);
216 assert(status >= -1 && status <= 1, "oob tri-state");
217 if (status == 0) {
218 if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
219 MethodHandles::is_signature_polymorphic_name(SystemDictionary::MethodHandle_klass(),
220 _pool->name_ref_at(cp_index))) {
221 // we may need a resolved_refs entry for the appendix
222 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
223 status = +1;
224 } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
225 MethodHandles::is_signature_polymorphic_name(SystemDictionary::VarHandle_klass(),
226 _pool->name_ref_at(cp_index))) {
227 // we may need a resolved_refs entry for the appendix
228 add_invokedynamic_resolved_references_entries(cp_index, cache_index);
229 status = +1;
230 } else {
231 status = -1;
232 }
233 _method_handle_invokers.at(cp_index) = status;
234 }
235 // We use a special internal bytecode for such methods (if non-static).
236 // The basic reason for this is that such methods need an extra "appendix" argument
237 // to transmit the call site's intended call type.
238 if (status > 0) {
239 (*opc) = (u1)Bytecodes::_invokehandle;
240 }
241 }
242 } else {
243 // Do not need to look at cp_index.
244 if ((*opc) == (u1)Bytecodes::_invokehandle) {
245 (*opc) = (u1)Bytecodes::_invokevirtual;
246 // Ignore corner case of original _invokespecial instruction.
247 // This is safe because (a) the signature polymorphic method was final, and
248 // (b) the implementation of MethodHandle will not call invokespecial on it.
249 }
250 }
251 }
252
253
254 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
255 address p = bcp + offset;
256 assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
257 if (!reverse) {
258 int cp_index = Bytes::get_Java_u2(p);
259 int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
260 int resolved_index = add_invokedynamic_resolved_references_entries(cp_index, cache_index);
261 // Replace the trailing four bytes with a CPC index for the dynamic
262 // call site. Unlike other CPC entries, there is one per bytecode,
263 // not just one per distinct CP entry. In other words, the
264 // CPC-to-CP relation is many-to-one for invokedynamic entries.
265 // This means we must use a larger index size than u2 to address
266 // all these entries. That is the main reason invokedynamic
267 // must have a five-byte instruction format. (Of course, other JVM
268 // implementations can use the bytes for other purposes.)
269 // Note: We use native_u4 format exclusively for 4-byte indexes.
270 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
271 // add the bcp in case we need to patch this bytecode if we also find a
272 // invokespecial/InterfaceMethodref in the bytecode stream
273 _patch_invokedynamic_bcps->push(p);
274 _patch_invokedynamic_refs->push(resolved_index);
275 } else {
276 int cache_index = ConstantPool::decode_invokedynamic_index(
277 Bytes::get_native_u4(p));
278 // We will reverse the bytecode rewriting _after_ adjusting them.
279 // Adjust the cache index by offset to the invokedynamic entries in the
280 // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
281 int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
282 int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
283 assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
284 // zero out 4 bytes
285 Bytes::put_Java_u4(p, 0);
286 Bytes::put_Java_u2(p, cp_index);
287 }
288 }
289
290 void Rewriter::patch_invokedynamic_bytecodes() {
291 // If the end of the cp_cache is the same as after initializing with the
292 // cpool, nothing needs to be done. Invokedynamic bytecodes are at the
293 // correct offsets. ie. no invokespecials added
294 int delta = cp_cache_delta();
295 if (delta > 0) {
296 int length = _patch_invokedynamic_bcps->length();
297 assert(length == _patch_invokedynamic_refs->length(),
298 "lengths should match");
299 for (int i = 0; i < length; i++) {
300 address p = _patch_invokedynamic_bcps->at(i);
301 int cache_index = ConstantPool::decode_invokedynamic_index(
302 Bytes::get_native_u4(p));
303 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
304
305 // invokedynamic resolved references map also points to cp cache and must
306 // add delta to each.
307 int resolved_index = _patch_invokedynamic_refs->at(i);
308 for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
309 assert(_invokedynamic_references_map.at(resolved_index + entry) == cache_index,
310 "should be the same index");
311 _invokedynamic_references_map.at_put(resolved_index+entry,
312 cache_index + delta);
313 }
314 }
315 }
316 }
317
318
319 // Rewrite some ldc bytecodes to _fast_aldc
320 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
321 bool reverse) {
322 if (!reverse) {
323 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
324 address p = bcp + offset;
325 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
326 constantTag tag = _pool->tag_at(cp_index).value();
327
328 if (tag.is_method_handle() ||
329 tag.is_method_type() ||
330 tag.is_string() ||
331 (tag.is_dynamic_constant() &&
332 // keep regular ldc interpreter logic for condy primitives
333 is_reference_type(FieldType::basic_type(_pool->uncached_signature_ref_at(cp_index))))
334 ) {
335 int ref_index = cp_entry_to_resolved_references(cp_index);
336 if (is_wide) {
337 (*bcp) = Bytecodes::_fast_aldc_w;
338 assert(ref_index == (u2)ref_index, "index overflow");
339 Bytes::put_native_u2(p, ref_index);
340 } else {
341 (*bcp) = Bytecodes::_fast_aldc;
342 assert(ref_index == (u1)ref_index, "index overflow");
343 (*p) = (u1)ref_index;
344 }
345 }
346 } else {
347 Bytecodes::Code rewritten_bc =
348 (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
349 if ((*bcp) == rewritten_bc) {
350 address p = bcp + offset;
351 int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
352 int pool_index = resolved_references_entry_to_pool_index(ref_index);
353 if (is_wide) {
354 (*bcp) = Bytecodes::_ldc_w;
355 assert(pool_index == (u2)pool_index, "index overflow");
356 Bytes::put_Java_u2(p, pool_index);
357 } else {
358 (*bcp) = Bytecodes::_ldc;
359 assert(pool_index == (u1)pool_index, "index overflow");
360 (*p) = (u1)pool_index;
361 }
362 }
363 }
364 }
365
366
367 // Rewrites a method given the index_map information
368 void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_error) {
369
370 int nof_jsrs = 0;
371 bool has_monitor_bytecodes = false;
372 Bytecodes::Code c;
373
374 // Bytecodes and their length
375 const address code_base = method->code_base();
376 const int code_length = method->code_size();
377
378 int bc_length;
379 for (int bci = 0; bci < code_length; bci += bc_length) {
380 address bcp = code_base + bci;
381 int prefix_length = 0;
382 c = (Bytecodes::Code)(*bcp);
383
384 // Since we have the code, see if we can get the length
385 // directly. Some more complicated bytecodes will report
386 // a length of zero, meaning we need to make another method
387 // call to calculate the length.
388 bc_length = Bytecodes::length_for(c);
389 if (bc_length == 0) {
390 bc_length = Bytecodes::length_at(method, bcp);
391
392 // length_at will put us at the bytecode after the one modified
393 // by 'wide'. We don't currently examine any of the bytecodes
394 // modified by wide, but in case we do in the future...
395 if (c == Bytecodes::_wide) {
396 prefix_length = 1;
397 c = (Bytecodes::Code)bcp[1];
398 }
399 }
400
401 assert(bc_length != 0, "impossible bytecode length");
402
403 switch (c) {
404 case Bytecodes::_lookupswitch : {
405 #ifndef CC_INTERP
406 Bytecode_lookupswitch bc(method, bcp);
407 (*bcp) = (
408 bc.number_of_pairs() < BinarySwitchThreshold
409 ? Bytecodes::_fast_linearswitch
410 : Bytecodes::_fast_binaryswitch
411 );
412 #endif
413 break;
414 }
415 case Bytecodes::_fast_linearswitch:
416 case Bytecodes::_fast_binaryswitch: {
417 #ifndef CC_INTERP
418 (*bcp) = Bytecodes::_lookupswitch;
419 #endif
420 break;
421 }
422
423 case Bytecodes::_invokespecial : {
424 rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
425 break;
426 }
427
428 case Bytecodes::_putstatic :
429 case Bytecodes::_putfield : {
430 if (!reverse) {
431 // Check if any final field of the class given as parameter is modified
432 // outside of initializer methods of the class. Fields that are modified
433 // are marked with a flag. For marked fields, the compilers do not perform
434 // constant folding (as the field can be changed after initialization).
435 //
436 // The check is performed after verification and only if verification has
437 // succeeded. Therefore, the class is guaranteed to be well-formed.
438 InstanceKlass* klass = method->method_holder();
439 u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
440 constantPoolHandle cp(method->constants());
441 Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
442
443 if (klass->name() == ref_class_name) {
444 Symbol* field_name = cp->name_ref_at(bc_index);
445 Symbol* field_sig = cp->signature_ref_at(bc_index);
446
447 fieldDescriptor fd;
448 if (klass->find_field(field_name, field_sig, &fd) != NULL) {
449 if (fd.access_flags().is_final()) {
450 if (fd.access_flags().is_static()) {
451 if (!method->is_static_initializer()) {
452 fd.set_has_initialized_final_update(true);
453 }
454 } else {
455 if (!method->is_object_initializer()) {
456 fd.set_has_initialized_final_update(true);
457 }
458 }
459 }
460 }
461 }
462 }
463 }
464 // fall through
465 case Bytecodes::_getstatic : // fall through
466 case Bytecodes::_getfield : // fall through
467 case Bytecodes::_vwithfield : // fall through but may require more checks for correctness
468 case Bytecodes::_invokevirtual : // fall through
469 case Bytecodes::_invokestatic :
470 case Bytecodes::_invokeinterface:
471 case Bytecodes::_invokehandle : // if reverse=true
472 rewrite_member_reference(bcp, prefix_length+1, reverse);
473 break;
474 case Bytecodes::_invokedynamic:
475 rewrite_invokedynamic(bcp, prefix_length+1, reverse);
476 break;
477 case Bytecodes::_ldc:
478 case Bytecodes::_fast_aldc: // if reverse=true
479 maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
480 break;
481 case Bytecodes::_ldc_w:
482 case Bytecodes::_fast_aldc_w: // if reverse=true
483 maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
484 break;
485 case Bytecodes::_jsr : // fall through
486 case Bytecodes::_jsr_w : nof_jsrs++; break;
487 case Bytecodes::_monitorenter : // fall through
488 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break;
489
490 default: break;
491 }
492 }
493
494 // Update access flags
495 if (has_monitor_bytecodes) {
496 method->set_has_monitor_bytecodes();
497 }
498
499 // The present of a jsr bytecode implies that the method might potentially
500 // have to be rewritten, so we run the oopMapGenerator on the method
501 if (nof_jsrs > 0) {
502 method->set_has_jsrs();
503 // Second pass will revisit this method.
504 assert(method->has_jsrs(), "didn't we just set this?");
505 }
506 }
507
508 // After constant pool is created, revisit methods containing jsrs.
509 methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) {
510 ResourceMark rm(THREAD);
511 ResolveOopMapConflicts romc(method);
512 methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle()));
513 // Update monitor matching info.
514 if (romc.monitor_safe()) {
515 new_method->set_guaranteed_monitor_matching();
516 }
517
518 return new_method;
519 }
520
521 void Rewriter::rewrite_bytecodes(TRAPS) {
522 assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
523
524 // determine index maps for Method* rewriting
525 compute_index_maps();
526
527 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
528 bool did_rewrite = false;
529 int i = _methods->length();
530 while (i-- > 0) {
531 Method* method = _methods->at(i);
532 if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
533 // rewrite the return bytecodes of Object.<init> to register the
534 // object for finalization if needed.
535 methodHandle m(THREAD, method);
536 rewrite_Object_init(m, CHECK);
537 did_rewrite = true;
538 break;
539 }
540 }
541 assert(did_rewrite, "must find Object::<init> to rewrite it");
542 }
543
544 // rewrite methods, in two passes
545 int len = _methods->length();
546 bool invokespecial_error = false;
547
548 for (int i = len-1; i >= 0; i--) {
549 Method* method = _methods->at(i);
550 scan_method(method, false, &invokespecial_error);
551 if (invokespecial_error) {
552 // If you get an error here, there is no reversing bytecodes
553 // This exception is stored for this class and no further attempt is
554 // made at verifying or rewriting.
555 THROW_MSG(vmSymbols::java_lang_InternalError(),
556 "This classfile overflows invokespecial for interfaces "
557 "and cannot be loaded");
558 return;
559 }
560 }
561
562 // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
563 // entries had to be added.
564 patch_invokedynamic_bytecodes();
565 }
566
567 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) {
568 if (!DumpSharedSpaces) {
569 assert(!klass->is_shared(), "archive methods must not be rewritten at run time");
570 }
571 ResourceMark rm(THREAD);
572 Rewriter rw(klass, klass->constants(), klass->methods(), CHECK);
573 // (That's all, folks.)
574 }
575
576 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
577 : _klass(klass),
578 _pool(cpool),
579 _methods(methods),
580 _cp_map(cpool->length()),
581 _cp_cache_map(cpool->length() / 2),
582 _reference_map(cpool->length()),
583 _resolved_references_map(cpool->length() / 2),
584 _invokedynamic_references_map(cpool->length() / 2),
585 _method_handle_invokers(cpool->length()),
586 _invokedynamic_cp_cache_map(cpool->length() / 4)
587 {
588
589 // Rewrite bytecodes - exception here exits.
590 rewrite_bytecodes(CHECK);
591
592 // Stress restoring bytecodes
593 if (StressRewriter) {
594 restore_bytecodes();
595 rewrite_bytecodes(CHECK);
596 }
597
598 // allocate constant pool cache, now that we've seen all the bytecodes
599 make_constant_pool_cache(THREAD);
600
601 // Restore bytecodes to their unrewritten state if there are exceptions
602 // rewriting bytecodes or allocating the cpCache
603 if (HAS_PENDING_EXCEPTION) {
604 restore_bytecodes();
605 return;
606 }
607
608 // Relocate after everything, but still do this under the is_rewritten flag,
609 // so methods with jsrs in custom class lists in aren't attempted to be
610 // rewritten in the RO section of the shared archive.
611 // Relocated bytecodes don't have to be restored, only the cp cache entries
612 int len = _methods->length();
613 for (int i = len-1; i >= 0; i--) {
614 methodHandle m(THREAD, _methods->at(i));
615
616 if (m->has_jsrs()) {
617 m = rewrite_jsrs(m, THREAD);
618 // Restore bytecodes to their unrewritten state if there are exceptions
619 // relocating bytecodes. If some are relocated, that is ok because that
620 // doesn't affect constant pool to cpCache rewriting.
621 if (HAS_PENDING_EXCEPTION) {
622 restore_bytecodes();
623 return;
624 }
625 // Method might have gotten rewritten.
626 methods->at_put(i, m());
627 }
628 }
629 }