1 /* 2 * Copyright (c) 1998, 2023, 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 "cds/metaspaceShared.hpp" 27 #include "classfile/vmClasses.hpp" 28 #include "interpreter/bytecodes.hpp" 29 #include "interpreter/bytecodeStream.hpp" 30 #include "interpreter/interpreter.hpp" 31 #include "interpreter/rewriter.hpp" 32 #include "memory/metadataFactory.hpp" 33 #include "memory/resourceArea.hpp" 34 #include "oops/generateOopMap.hpp" 35 #include "oops/resolvedIndyEntry.hpp" 36 #include "prims/methodHandles.hpp" 37 #include "runtime/arguments.hpp" 38 #include "runtime/fieldDescriptor.inline.hpp" 39 #include "runtime/handles.inline.hpp" 40 41 // Computes a CPC map (new_index -> original_index) for constant pool entries 42 // that are referred to by the interpreter at runtime via the constant pool cache. 43 // Also computes a CP map (original_index -> new_index). 44 // Marks entries in CP which require additional processing. 45 void Rewriter::compute_index_maps() { 46 const int length = _pool->length(); 47 init_maps(length); 48 bool saw_mh_symbol = false; 49 for (int i = 0; i < length; i++) { 50 int tag = _pool->tag_at(i).value(); 51 switch (tag) { 52 case JVM_CONSTANT_InterfaceMethodref: 53 case JVM_CONSTANT_Fieldref : // fall through 54 case JVM_CONSTANT_Methodref : // fall through 55 add_cp_cache_entry(i); 56 break; 57 case JVM_CONSTANT_Dynamic: 58 assert(_pool->has_dynamic_constant(), "constant pool's _has_dynamic_constant flag not set"); 59 add_resolved_references_entry(i); 60 break; 61 case JVM_CONSTANT_String : // fall through 62 case JVM_CONSTANT_MethodHandle : // fall through 63 case JVM_CONSTANT_MethodType : // fall through 64 add_resolved_references_entry(i); 65 break; 66 case JVM_CONSTANT_Utf8: 67 if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() || 68 _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) { 69 saw_mh_symbol = true; 70 } 71 break; 72 } 73 } 74 75 // Record limits of resolved reference map for constant pool cache indices 76 record_map_limits(); 77 78 guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1), 79 "all cp cache indexes fit in a u2"); 80 81 if (saw_mh_symbol) { 82 _method_handle_invokers.at_grow(length, 0); 83 } 84 } 85 86 // Unrewrite the bytecodes if an error occurs. 87 void Rewriter::restore_bytecodes(Thread* thread) { 88 int len = _methods->length(); 89 bool invokespecial_error = false; 90 91 for (int i = len-1; i >= 0; i--) { 92 Method* method = _methods->at(i); 93 scan_method(thread, method, true, &invokespecial_error); 94 assert(!invokespecial_error, "reversing should not get an invokespecial error"); 95 } 96 } 97 98 // Creates a constant pool cache given a CPC map 99 void Rewriter::make_constant_pool_cache(TRAPS) { 100 ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data(); 101 ConstantPoolCache* cache = 102 ConstantPoolCache::allocate(loader_data, _cp_cache_map, 103 _invokedynamic_references_map, _initialized_indy_entries, CHECK); 104 105 // initialize object cache in constant pool 106 _pool->set_cache(cache); 107 cache->set_constant_pool(_pool()); 108 109 // _resolved_references is stored in pool->cache(), so need to be done after 110 // the above lines. 111 _pool->initialize_resolved_references(loader_data, _resolved_references_map, 112 _resolved_reference_limit, 113 THREAD); 114 #if INCLUDE_CDS 115 if (!HAS_PENDING_EXCEPTION && Arguments::is_dumping_archive()) { 116 if (_pool->pool_holder()->is_shared()) { 117 assert(DynamicDumpSharedSpaces, "must be"); 118 // We are linking a shared class from the base archive. This 119 // class won't be written into the dynamic archive, so there's no 120 // need to save its CpCaches. 121 } else { 122 cache->save_for_archive(THREAD); 123 } 124 } 125 #endif 126 127 // Clean up constant pool cache if initialize_resolved_references() failed. 128 if (HAS_PENDING_EXCEPTION) { 129 MetadataFactory::free_metadata(loader_data, cache); 130 _pool->set_cache(nullptr); // so the verifier isn't confused 131 } 132 } 133 134 135 136 // The new finalization semantics says that registration of 137 // finalizable objects must be performed on successful return from the 138 // Object.<init> constructor. We could implement this trivially if 139 // <init> were never rewritten but since JVMTI allows this to occur, a 140 // more complicated solution is required. A special return bytecode 141 // is used only by Object.<init> to signal the finalization 142 // registration point. Additionally local 0 must be preserved so it's 143 // available to pass to the registration function. For simplicity we 144 // require that local 0 is never overwritten so it's available as an 145 // argument for registration. 146 147 void Rewriter::rewrite_Object_init(const methodHandle& method, TRAPS) { 148 RawBytecodeStream bcs(method); 149 while (!bcs.is_last_bytecode()) { 150 Bytecodes::Code opcode = bcs.raw_next(); 151 switch (opcode) { 152 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break; 153 154 case Bytecodes::_istore: 155 case Bytecodes::_lstore: 156 case Bytecodes::_fstore: 157 case Bytecodes::_dstore: 158 case Bytecodes::_astore: 159 if (bcs.get_index() != 0) continue; 160 161 // fall through 162 case Bytecodes::_istore_0: 163 case Bytecodes::_lstore_0: 164 case Bytecodes::_fstore_0: 165 case Bytecodes::_dstore_0: 166 case Bytecodes::_astore_0: 167 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(), 168 "can't overwrite local 0 in Object.<init>"); 169 break; 170 171 default: 172 break; 173 } 174 } 175 } 176 177 178 // Rewrite a classfile-order CP index into a native-order CPC index. 179 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) { 180 address p = bcp + offset; 181 if (!reverse) { 182 int cp_index = Bytes::get_Java_u2(p); 183 int cache_index = cp_entry_to_cp_cache(cp_index); 184 Bytes::put_native_u2(p, (u2)cache_index); 185 if (!_method_handle_invokers.is_empty()) 186 maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse); 187 } else { 188 int cache_index = Bytes::get_native_u2(p); 189 int pool_index = cp_cache_entry_pool_index(cache_index); 190 Bytes::put_Java_u2(p, (u2)pool_index); 191 if (!_method_handle_invokers.is_empty()) 192 maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse); 193 } 194 } 195 196 // If the constant pool entry for invokespecial is InterfaceMethodref, 197 // we need to add a separate cpCache entry for its resolution, because it is 198 // different than the resolution for invokeinterface with InterfaceMethodref. 199 // These cannot share cpCache entries. 200 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) { 201 address p = bcp + offset; 202 if (!reverse) { 203 int cp_index = Bytes::get_Java_u2(p); 204 if (_pool->tag_at(cp_index).is_interface_method()) { 205 int cache_index = add_invokespecial_cp_cache_entry(cp_index); 206 if (cache_index != (int)(jushort) cache_index) { 207 *invokespecial_error = true; 208 } 209 Bytes::put_native_u2(p, (u2)cache_index); 210 } else { 211 rewrite_member_reference(bcp, offset, reverse); 212 } 213 } else { 214 rewrite_member_reference(bcp, offset, reverse); 215 } 216 } 217 218 219 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.) 220 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) { 221 if (!reverse) { 222 if ((*opc) == (u1)Bytecodes::_invokevirtual || 223 // allow invokespecial as an alias, although it would be very odd: 224 (*opc) == (u1)Bytecodes::_invokespecial) { 225 assert(_pool->tag_at(cp_index).is_method(), "wrong index"); 226 // Determine whether this is a signature-polymorphic method. 227 if (cp_index >= _method_handle_invokers.length()) return; 228 int status = _method_handle_invokers.at(cp_index); 229 assert(status >= -1 && status <= 1, "oob tri-state"); 230 if (status == 0) { 231 if (_pool->uncached_klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() && 232 MethodHandles::is_signature_polymorphic_name(vmClasses::MethodHandle_klass(), 233 _pool->uncached_name_ref_at(cp_index))) { 234 // we may need a resolved_refs entry for the appendix 235 add_invokedynamic_resolved_references_entry(cp_index, cache_index); 236 status = +1; 237 } else if (_pool->uncached_klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() && 238 MethodHandles::is_signature_polymorphic_name(vmClasses::VarHandle_klass(), 239 _pool->uncached_name_ref_at(cp_index))) { 240 // we may need a resolved_refs entry for the appendix 241 add_invokedynamic_resolved_references_entry(cp_index, cache_index); 242 status = +1; 243 } else { 244 status = -1; 245 } 246 _method_handle_invokers.at(cp_index) = status; 247 } 248 // We use a special internal bytecode for such methods (if non-static). 249 // The basic reason for this is that such methods need an extra "appendix" argument 250 // to transmit the call site's intended call type. 251 if (status > 0) { 252 (*opc) = (u1)Bytecodes::_invokehandle; 253 } 254 } 255 } else { 256 // Do not need to look at cp_index. 257 if ((*opc) == (u1)Bytecodes::_invokehandle) { 258 (*opc) = (u1)Bytecodes::_invokevirtual; 259 // Ignore corner case of original _invokespecial instruction. 260 // This is safe because (a) the signature polymorphic method was final, and 261 // (b) the implementation of MethodHandle will not call invokespecial on it. 262 } 263 } 264 } 265 266 267 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) { 268 address p = bcp + offset; 269 assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode"); 270 if (!reverse) { 271 int cp_index = Bytes::get_Java_u2(p); 272 int resolved_index = add_invokedynamic_resolved_references_entry(cp_index, -1); // Indy no longer has a CPCE 273 // Replace the trailing four bytes with an index to the array of 274 // indy resolution information in the CPC. There is one entry for 275 // each bytecode, even if they make the same call. In other words, 276 // the CPC-to-CP relation is many-to-one for invokedynamic entries. 277 // This means we must use a larger index size than u2 to address 278 // all these entries. That is the main reason invokedynamic 279 // must have a five-byte instruction format. (Of course, other JVM 280 // implementations can use the bytes for other purposes.) 281 // Note: We use native_u4 format exclusively for 4-byte indexes. 282 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(_invokedynamic_index)); 283 _invokedynamic_index++; 284 285 // Collect invokedynamic information before creating ResolvedInvokeDynamicInfo array 286 _initialized_indy_entries.push(ResolvedIndyEntry((u2)resolved_index, (u2)cp_index)); 287 } else { 288 // Should do nothing since we are not patching this bytecode 289 int cache_index = ConstantPool::decode_invokedynamic_index( 290 Bytes::get_native_u4(p)); 291 int cp_index = _initialized_indy_entries.at(cache_index).constant_pool_index(); 292 assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index"); 293 // zero out 4 bytes 294 Bytes::put_Java_u4(p, 0); 295 Bytes::put_Java_u2(p, (u2)cp_index); 296 } 297 } 298 299 // Rewrite some ldc bytecodes to _fast_aldc 300 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide, 301 bool reverse) { 302 if (!reverse) { 303 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode"); 304 address p = bcp + offset; 305 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p); 306 constantTag tag = _pool->tag_at(cp_index).value(); 307 308 if (tag.is_method_handle() || 309 tag.is_method_type() || 310 tag.is_string() || 311 (tag.is_dynamic_constant() && 312 // keep regular ldc interpreter logic for condy primitives 313 is_reference_type(Signature::basic_type(_pool->uncached_signature_ref_at(cp_index)))) 314 ) { 315 int ref_index = cp_entry_to_resolved_references(cp_index); 316 if (is_wide) { 317 (*bcp) = Bytecodes::_fast_aldc_w; 318 assert(ref_index == (u2)ref_index, "index overflow"); 319 Bytes::put_native_u2(p, (u2)ref_index); 320 } else { 321 (*bcp) = Bytecodes::_fast_aldc; 322 assert(ref_index == (u1)ref_index, "index overflow"); 323 (*p) = (u1)ref_index; 324 } 325 } 326 } else { 327 Bytecodes::Code rewritten_bc = 328 (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc); 329 if ((*bcp) == rewritten_bc) { 330 address p = bcp + offset; 331 int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p); 332 int pool_index = resolved_references_entry_to_pool_index(ref_index); 333 if (is_wide) { 334 (*bcp) = Bytecodes::_ldc_w; 335 assert(pool_index == (u2)pool_index, "index overflow"); 336 Bytes::put_Java_u2(p, (u2)pool_index); 337 } else { 338 (*bcp) = Bytecodes::_ldc; 339 assert(pool_index == (u1)pool_index, "index overflow"); 340 (*p) = (u1)pool_index; 341 } 342 } 343 } 344 } 345 346 347 // Rewrites a method given the index_map information 348 void Rewriter::scan_method(Thread* thread, Method* method, bool reverse, bool* invokespecial_error) { 349 350 int nof_jsrs = 0; 351 bool has_monitor_bytecodes = false; 352 Bytecodes::Code c; 353 354 // Bytecodes and their length 355 const address code_base = method->code_base(); 356 const int code_length = method->code_size(); 357 358 int bc_length; 359 for (int bci = 0; bci < code_length; bci += bc_length) { 360 address bcp = code_base + bci; 361 int prefix_length = 0; 362 c = (Bytecodes::Code)(*bcp); 363 364 // Since we have the code, see if we can get the length 365 // directly. Some more complicated bytecodes will report 366 // a length of zero, meaning we need to make another method 367 // call to calculate the length. 368 bc_length = Bytecodes::length_for(c); 369 if (bc_length == 0) { 370 bc_length = Bytecodes::length_at(method, bcp); 371 372 // length_at will put us at the bytecode after the one modified 373 // by 'wide'. We don't currently examine any of the bytecodes 374 // modified by wide, but in case we do in the future... 375 if (c == Bytecodes::_wide) { 376 prefix_length = 1; 377 c = (Bytecodes::Code)bcp[1]; 378 } 379 } 380 381 // Continuing with an invalid bytecode will fail in the loop below. 382 // So guarantee here. 383 guarantee(bc_length > 0, "Verifier should have caught this invalid bytecode"); 384 385 switch (c) { 386 case Bytecodes::_lookupswitch : { 387 #ifndef ZERO 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 ZERO 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(thread, method->constants()); 423 Symbol* ref_class_name = cp->klass_name_at(cp->uncached_klass_ref_index_at(bc_index)); 424 425 if (klass->name() == ref_class_name) { 426 Symbol* field_name = cp->uncached_name_ref_at(bc_index); 427 Symbol* field_sig = cp->uncached_signature_ref_at(bc_index); 428 429 fieldDescriptor fd; 430 if (klass->find_field(field_name, field_sig, &fd) != nullptr) { 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 default: break; 472 } 473 } 474 475 // Update flags 476 if (has_monitor_bytecodes) { 477 method->set_has_monitor_bytecodes(); 478 } 479 480 // The present of a jsr bytecode implies that the method might potentially 481 // have to be rewritten, so we run the oopMapGenerator on the method 482 if (nof_jsrs > 0) { 483 method->set_has_jsrs(); 484 } 485 } 486 487 // After constant pool is created, revisit methods containing jsrs. 488 methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) { 489 ResourceMark rm(THREAD); 490 ResolveOopMapConflicts romc(method); 491 methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle())); 492 // Update monitor matching info. 493 if (romc.monitor_safe()) { 494 new_method->set_guaranteed_monitor_matching(); 495 } 496 497 return new_method; 498 } 499 500 void Rewriter::rewrite_bytecodes(TRAPS) { 501 assert(_pool->cache() == nullptr, "constant pool cache must not be set yet"); 502 503 // determine index maps for Method* rewriting 504 compute_index_maps(); 505 506 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) { 507 bool did_rewrite = false; 508 int i = _methods->length(); 509 while (i-- > 0) { 510 Method* method = _methods->at(i); 511 if (method->intrinsic_id() == vmIntrinsics::_Object_init) { 512 // rewrite the return bytecodes of Object.<init> to register the 513 // object for finalization if needed. 514 methodHandle m(THREAD, method); 515 rewrite_Object_init(m, CHECK); 516 did_rewrite = true; 517 break; 518 } 519 } 520 assert(did_rewrite, "must find Object::<init> to rewrite it"); 521 } 522 523 // rewrite methods, in two passes 524 int len = _methods->length(); 525 bool invokespecial_error = false; 526 527 for (int i = len-1; i >= 0; i--) { 528 Method* method = _methods->at(i); 529 scan_method(THREAD, method, false, &invokespecial_error); 530 if (invokespecial_error) { 531 // If you get an error here, there is no reversing bytecodes 532 // This exception is stored for this class and no further attempt is 533 // made at verifying or rewriting. 534 THROW_MSG(vmSymbols::java_lang_InternalError(), 535 "This classfile overflows invokespecial for interfaces " 536 "and cannot be loaded"); 537 return; 538 } 539 } 540 } 541 542 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) { 543 #if INCLUDE_CDS 544 if (klass->is_shared()) { 545 assert(!klass->is_rewritten(), "rewritten shared classes cannot be rewritten again"); 546 } 547 #endif // INCLUDE_CDS 548 ResourceMark rm(THREAD); 549 constantPoolHandle cpool(THREAD, klass->constants()); 550 Rewriter rw(klass, cpool, klass->methods(), CHECK); 551 // (That's all, folks.) 552 } 553 554 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS) 555 : _klass(klass), 556 _pool(cpool), 557 _methods(methods), 558 _cp_map(cpool->length()), 559 _cp_cache_map(cpool->length() / 2), 560 _reference_map(cpool->length()), 561 _resolved_references_map(cpool->length() / 2), 562 _invokedynamic_references_map(cpool->length() / 2), 563 _method_handle_invokers(cpool->length()), 564 _invokedynamic_index(0) 565 { 566 567 // Rewrite bytecodes - exception here exits. 568 rewrite_bytecodes(CHECK); 569 570 // Stress restoring bytecodes 571 if (StressRewriter) { 572 restore_bytecodes(THREAD); 573 rewrite_bytecodes(CHECK); 574 } 575 576 // allocate constant pool cache, now that we've seen all the bytecodes 577 make_constant_pool_cache(THREAD); 578 579 // Restore bytecodes to their unrewritten state if there are exceptions 580 // rewriting bytecodes or allocating the cpCache 581 if (HAS_PENDING_EXCEPTION) { 582 restore_bytecodes(THREAD); 583 return; 584 } 585 586 // Relocate after everything, but still do this under the is_rewritten flag, 587 // so methods with jsrs in custom class lists in aren't attempted to be 588 // rewritten in the RO section of the shared archive. 589 // Relocated bytecodes don't have to be restored, only the cp cache entries 590 int len = _methods->length(); 591 for (int i = len-1; i >= 0; i--) { 592 methodHandle m(THREAD, _methods->at(i)); 593 594 if (m->has_jsrs()) { 595 m = rewrite_jsrs(m, THREAD); 596 // Restore bytecodes to their unrewritten state if there are exceptions 597 // relocating bytecodes. If some are relocated, that is ok because that 598 // doesn't affect constant pool to cpCache rewriting. 599 if (HAS_PENDING_EXCEPTION) { 600 restore_bytecodes(THREAD); 601 return; 602 } 603 // Method might have gotten rewritten. 604 methods->at_put(i, m()); 605 } 606 } 607 }