1 /*
  2  * Copyright (c) 1998, 2021, 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/interpreter.hpp"
 30 #include "interpreter/rewriter.hpp"
 31 #include "memory/metadataFactory.hpp"
 32 #include "memory/resourceArea.hpp"
 33 #include "oops/constantPool.hpp"
 34 #include "oops/generateOopMap.hpp"
 35 #include "prims/methodHandles.hpp"
 36 #include "runtime/fieldDescriptor.inline.hpp"
 37 #include "runtime/handles.inline.hpp"
 38 
 39 // Computes a CPC map (new_index -> original_index) for constant pool entries
 40 // that are referred to by the interpreter at runtime via the constant pool cache.
 41 // Also computes a CP map (original_index -> new_index).
 42 // Marks entries in CP which require additional processing.
 43 void Rewriter::compute_index_maps() {
 44   const int length  = _pool->length();
 45   init_maps(length);
 46   bool saw_mh_symbol = false;
 47   for (int i = 0; i < length; i++) {
 48     int tag = _pool->tag_at(i).value();
 49     switch (tag) {
 50       case JVM_CONSTANT_InterfaceMethodref:
 51       case JVM_CONSTANT_Fieldref          : // fall through
 52       case JVM_CONSTANT_Methodref         : // fall through
 53         add_cp_cache_entry(i);
 54         break;
 55       case JVM_CONSTANT_Dynamic:
 56         assert(_pool->has_dynamic_constant(), "constant pool's _has_dynamic_constant flag not set");
 57         add_resolved_references_entry(i);
 58         break;
 59       case JVM_CONSTANT_String            : // fall through
 60       case JVM_CONSTANT_MethodHandle      : // fall through
 61       case JVM_CONSTANT_MethodType        : // fall through
 62         add_resolved_references_entry(i);
 63         break;
 64       case JVM_CONSTANT_Utf8:
 65         if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
 66             _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
 67           saw_mh_symbol = true;
 68         }
 69         break;
 70     }
 71   }
 72 
 73   // Record limits of resolved reference map for constant pool cache indices
 74   record_map_limits();
 75 
 76   guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
 77             "all cp cache indexes fit in a u2");
 78 
 79   if (saw_mh_symbol) {
 80     _method_handle_invokers.at_grow(length, 0);
 81   }
 82 }
 83 
 84 // Unrewrite the bytecodes if an error occurs.
 85 void Rewriter::restore_bytecodes(Thread* thread) {
 86   int len = _methods->length();
 87   bool invokespecial_error = false;
 88 
 89   for (int i = len-1; i >= 0; i--) {
 90     Method* method = _methods->at(i);
 91     scan_method(thread, method, true, &invokespecial_error);
 92     assert(!invokespecial_error, "reversing should not get an invokespecial error");
 93   }
 94 }
 95 
 96 // Creates a constant pool cache given a CPC map
 97 void Rewriter::make_constant_pool_cache(TRAPS) {
 98   ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
 99   ConstantPoolCache* cache =
100       ConstantPoolCache::allocate(loader_data, _cp_cache_map,
101                                   _invokedynamic_cp_cache_map,
102                                   _invokedynamic_references_map, CHECK);
103 
104   // initialize object cache in constant pool
105   _pool->set_cache(cache);
106   cache->set_constant_pool(_pool());
107 
108   // _resolved_references is stored in pool->cache(), so need to be done after
109   // the above lines.
110   _pool->initialize_resolved_references(loader_data, _resolved_references_map,
111                                         _resolved_reference_limit,
112                                         THREAD);
113 
114   // Clean up constant pool cache if initialize_resolved_references() failed.
115   if (HAS_PENDING_EXCEPTION) {
116     MetadataFactory::free_metadata(loader_data, cache);
117     _pool->set_cache(NULL);  // so the verifier isn't confused
118   } else {
119     DEBUG_ONLY(
120     if (DumpSharedSpaces) {
121       cache->verify_just_initialized();
122     })
123   }
124 }
125 
126 
127 
128 // The new finalization semantics says that registration of
129 // finalizable objects must be performed on successful return from the
130 // Object.<init> constructor.  We could implement this trivially if
131 // <init> were never rewritten but since JVMTI allows this to occur, a
132 // more complicated solution is required.  A special return bytecode
133 // is used only by Object.<init> to signal the finalization
134 // registration point.  Additionally local 0 must be preserved so it's
135 // available to pass to the registration function.  For simplicity we
136 // require that local 0 is never overwritten so it's available as an
137 // argument for registration.
138 
139 void Rewriter::rewrite_Object_init(const methodHandle& method, TRAPS) {
140   RawBytecodeStream bcs(method);
141   while (!bcs.is_last_bytecode()) {
142     Bytecodes::Code opcode = bcs.raw_next();
143     switch (opcode) {
144       case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
145 
146       case Bytecodes::_istore:
147       case Bytecodes::_lstore:
148       case Bytecodes::_fstore:
149       case Bytecodes::_dstore:
150       case Bytecodes::_astore:
151         if (bcs.get_index() != 0) continue;
152 
153         // fall through
154       case Bytecodes::_istore_0:
155       case Bytecodes::_lstore_0:
156       case Bytecodes::_fstore_0:
157       case Bytecodes::_dstore_0:
158       case Bytecodes::_astore_0:
159         THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
160                   "can't overwrite local 0 in Object.<init>");
161         break;
162 
163       default:
164         break;
165     }
166   }
167 }
168 
169 
170 // Rewrite a classfile-order CP index into a native-order CPC index.
171 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
172   address p = bcp + offset;
173   if (!reverse) {
174     int  cp_index    = Bytes::get_Java_u2(p);
175     int  cache_index = cp_entry_to_cp_cache(cp_index);
176     Bytes::put_native_u2(p, cache_index);
177     if (!_method_handle_invokers.is_empty())
178       maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
179   } else {
180     int cache_index = Bytes::get_native_u2(p);
181     int pool_index = cp_cache_entry_pool_index(cache_index);
182     Bytes::put_Java_u2(p, pool_index);
183     if (!_method_handle_invokers.is_empty())
184       maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
185   }
186 }
187 
188 // If the constant pool entry for invokespecial is InterfaceMethodref,
189 // we need to add a separate cpCache entry for its resolution, because it is
190 // different than the resolution for invokeinterface with InterfaceMethodref.
191 // These cannot share cpCache entries.
192 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
193   address p = bcp + offset;
194   if (!reverse) {
195     int cp_index = Bytes::get_Java_u2(p);
196     if (_pool->tag_at(cp_index).is_interface_method()) {
197       int cache_index = add_invokespecial_cp_cache_entry(cp_index);
198       if (cache_index != (int)(jushort) cache_index) {
199         *invokespecial_error = true;
200       }
201       Bytes::put_native_u2(p, cache_index);
202     } else {
203       rewrite_member_reference(bcp, offset, reverse);
204     }
205   } else {
206     rewrite_member_reference(bcp, offset, reverse);
207   }
208 }
209 
210 
211 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
212 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
213   if (!reverse) {
214     if ((*opc) == (u1)Bytecodes::_invokevirtual ||
215         // allow invokespecial as an alias, although it would be very odd:
216         (*opc) == (u1)Bytecodes::_invokespecial) {
217       assert(_pool->tag_at(cp_index).is_method(), "wrong index");
218       // Determine whether this is a signature-polymorphic method.
219       if (cp_index >= _method_handle_invokers.length())  return;
220       int status = _method_handle_invokers.at(cp_index);
221       assert(status >= -1 && status <= 1, "oob tri-state");
222       if (status == 0) {
223         if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
224             MethodHandles::is_signature_polymorphic_name(vmClasses::MethodHandle_klass(),
225                                                          _pool->name_ref_at(cp_index))) {
226           // we may need a resolved_refs entry for the appendix
227           add_invokedynamic_resolved_references_entry(cp_index, cache_index);
228           status = +1;
229         } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
230                    MethodHandles::is_signature_polymorphic_name(vmClasses::VarHandle_klass(),
231                                                                 _pool->name_ref_at(cp_index))) {
232           // we may need a resolved_refs entry for the appendix
233           add_invokedynamic_resolved_references_entry(cp_index, cache_index);
234           status = +1;
235         } else {
236           status = -1;
237         }
238         _method_handle_invokers.at(cp_index) = status;
239       }
240       // We use a special internal bytecode for such methods (if non-static).
241       // The basic reason for this is that such methods need an extra "appendix" argument
242       // to transmit the call site's intended call type.
243       if (status > 0) {
244         (*opc) = (u1)Bytecodes::_invokehandle;
245       }
246     }
247   } else {
248     // Do not need to look at cp_index.
249     if ((*opc) == (u1)Bytecodes::_invokehandle) {
250       (*opc) = (u1)Bytecodes::_invokevirtual;
251       // Ignore corner case of original _invokespecial instruction.
252       // This is safe because (a) the signature polymorphic method was final, and
253       // (b) the implementation of MethodHandle will not call invokespecial on it.
254     }
255   }
256 }
257 
258 
259 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
260   address p = bcp + offset;
261   assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
262   if (!reverse) {
263     int cp_index = Bytes::get_Java_u2(p);
264     int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
265     int resolved_index = add_invokedynamic_resolved_references_entry(cp_index, cache_index);
266     // Replace the trailing four bytes with a CPC index for the dynamic
267     // call site.  Unlike other CPC entries, there is one per bytecode,
268     // not just one per distinct CP entry.  In other words, the
269     // CPC-to-CP relation is many-to-one for invokedynamic entries.
270     // This means we must use a larger index size than u2 to address
271     // all these entries.  That is the main reason invokedynamic
272     // must have a five-byte instruction format.  (Of course, other JVM
273     // implementations can use the bytes for other purposes.)
274     // Note: We use native_u4 format exclusively for 4-byte indexes.
275     Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
276     // add the bcp in case we need to patch this bytecode if we also find a
277     // invokespecial/InterfaceMethodref in the bytecode stream
278     _patch_invokedynamic_bcps->push(p);
279     _patch_invokedynamic_refs->push(resolved_index);
280   } else {
281     int cache_index = ConstantPool::decode_invokedynamic_index(
282                         Bytes::get_native_u4(p));
283     // We will reverse the bytecode rewriting _after_ adjusting them.
284     // Adjust the cache index by offset to the invokedynamic entries in the
285     // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
286     int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
287     int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
288     assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
289     // zero out 4 bytes
290     Bytes::put_Java_u4(p, 0);
291     Bytes::put_Java_u2(p, cp_index);
292   }
293 }
294 
295 void Rewriter::patch_invokedynamic_bytecodes() {
296   // If the end of the cp_cache is the same as after initializing with the
297   // cpool, nothing needs to be done.  Invokedynamic bytecodes are at the
298   // correct offsets. ie. no invokespecials added
299   int delta = cp_cache_delta();
300   if (delta > 0) {
301     int length = _patch_invokedynamic_bcps->length();
302     assert(length == _patch_invokedynamic_refs->length(),
303            "lengths should match");
304     for (int i = 0; i < length; i++) {
305       address p = _patch_invokedynamic_bcps->at(i);
306       int cache_index = ConstantPool::decode_invokedynamic_index(
307                           Bytes::get_native_u4(p));
308       Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
309 
310       // invokedynamic resolved references map also points to cp cache and must
311       // add delta to each.
312       int resolved_index = _patch_invokedynamic_refs->at(i);
313         assert(_invokedynamic_references_map.at(resolved_index) == cache_index,
314              "should be the same index");
315         _invokedynamic_references_map.at_put(resolved_index, cache_index + delta);
316     }
317   }
318 }
319 
320 
321 // Rewrite some ldc bytecodes to _fast_aldc
322 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
323                                  bool reverse) {
324   if (!reverse) {
325     assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
326     address p = bcp + offset;
327     int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
328     constantTag tag = _pool->tag_at(cp_index).value();
329 
330     if (tag.is_method_handle() ||
331         tag.is_method_type() ||
332         tag.is_string() ||
333         (tag.is_dynamic_constant() &&
334          // keep regular ldc interpreter logic for condy primitives
335          is_reference_type(Signature::basic_type(_pool->uncached_signature_ref_at(cp_index))))
336         ) {
337       int ref_index = cp_entry_to_resolved_references(cp_index);
338       if (is_wide) {
339         (*bcp) = Bytecodes::_fast_aldc_w;
340         assert(ref_index == (u2)ref_index, "index overflow");
341         Bytes::put_native_u2(p, ref_index);
342       } else {
343         (*bcp) = Bytecodes::_fast_aldc;
344         assert(ref_index == (u1)ref_index, "index overflow");
345         (*p) = (u1)ref_index;
346       }
347     }
348   } else {
349     Bytecodes::Code rewritten_bc =
350               (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
351     if ((*bcp) == rewritten_bc) {
352       address p = bcp + offset;
353       int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
354       int pool_index = resolved_references_entry_to_pool_index(ref_index);
355       if (is_wide) {
356         (*bcp) = Bytecodes::_ldc_w;
357         assert(pool_index == (u2)pool_index, "index overflow");
358         Bytes::put_Java_u2(p, pool_index);
359       } else {
360         (*bcp) = Bytecodes::_ldc;
361         assert(pool_index == (u1)pool_index, "index overflow");
362         (*p) = (u1)pool_index;
363       }
364     }
365   }
366 }
367 
368 
369 // Rewrites a method given the index_map information
370 void Rewriter::scan_method(Thread* thread, Method* method, bool reverse, bool* invokespecial_error) {
371 
372   int nof_jsrs = 0;
373   bool has_monitor_bytecodes = false;
374   Bytecodes::Code c;
375 
376   // Bytecodes and their length
377   const address code_base = method->code_base();
378   const int code_length = method->code_size();
379 
380   int bc_length;
381   for (int bci = 0; bci < code_length; bci += bc_length) {
382     address bcp = code_base + bci;
383     int prefix_length = 0;
384     c = (Bytecodes::Code)(*bcp);
385 
386     // Since we have the code, see if we can get the length
387     // directly. Some more complicated bytecodes will report
388     // a length of zero, meaning we need to make another method
389     // call to calculate the length.
390     bc_length = Bytecodes::length_for(c);
391     if (bc_length == 0) {
392       bc_length = Bytecodes::length_at(method, bcp);
393 
394       // length_at will put us at the bytecode after the one modified
395       // by 'wide'. We don't currently examine any of the bytecodes
396       // modified by wide, but in case we do in the future...
397       if (c == Bytecodes::_wide) {
398         prefix_length = 1;
399         c = (Bytecodes::Code)bcp[1];
400       }
401     }
402 
403     // Continuing with an invalid bytecode will fail in the loop below.
404     // So guarantee here.
405     guarantee(bc_length > 0, "Verifier should have caught this invalid bytecode");
406 
407     switch (c) {
408       case Bytecodes::_lookupswitch   : {
409 #ifndef ZERO
410         Bytecode_lookupswitch bc(method, bcp);
411         (*bcp) = (
412           bc.number_of_pairs() < BinarySwitchThreshold
413           ? Bytecodes::_fast_linearswitch
414           : Bytecodes::_fast_binaryswitch
415         );
416 #endif
417         break;
418       }
419       case Bytecodes::_fast_linearswitch:
420       case Bytecodes::_fast_binaryswitch: {
421 #ifndef ZERO
422         (*bcp) = Bytecodes::_lookupswitch;
423 #endif
424         break;
425       }
426 
427       case Bytecodes::_invokespecial  : {
428         rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
429         break;
430       }
431 
432       case Bytecodes::_putstatic      :
433       case Bytecodes::_putfield       : {
434         if (!reverse) {
435           // Check if any final field of the class given as parameter is modified
436           // outside of initializer methods of the class. Fields that are modified
437           // are marked with a flag. For marked fields, the compilers do not perform
438           // constant folding (as the field can be changed after initialization).
439           //
440           // The check is performed after verification and only if verification has
441           // succeeded. Therefore, the class is guaranteed to be well-formed.
442           InstanceKlass* klass = method->method_holder();
443           u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
444           constantPoolHandle cp(thread, method->constants());
445           Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
446 
447           if (klass->name() == ref_class_name) {
448             Symbol* field_name = cp->name_ref_at(bc_index);
449             Symbol* field_sig = cp->signature_ref_at(bc_index);
450 
451             fieldDescriptor fd;
452             if (klass->find_field(field_name, field_sig, &fd) != NULL) {
453               if (fd.access_flags().is_final()) {
454                 if (fd.access_flags().is_static()) {
455                   if (!method->is_static_initializer()) {
456                     fd.set_has_initialized_final_update(true);
457                   }
458                 } else {
459                   if (!method->is_object_initializer()) {
460                     fd.set_has_initialized_final_update(true);
461                   }
462                 }
463               }
464             }
465           }
466         }
467       }
468       // fall through
469       case Bytecodes::_getstatic      : // fall through
470       case Bytecodes::_getfield       : // fall through
471       case Bytecodes::_invokevirtual  : // fall through
472       case Bytecodes::_invokestatic   :
473       case Bytecodes::_invokeinterface:
474       case Bytecodes::_invokehandle   : // if reverse=true
475         rewrite_member_reference(bcp, prefix_length+1, reverse);
476         break;
477       case Bytecodes::_invokedynamic:
478         rewrite_invokedynamic(bcp, prefix_length+1, reverse);
479         break;
480       case Bytecodes::_ldc:
481       case Bytecodes::_fast_aldc:  // if reverse=true
482         maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
483         break;
484       case Bytecodes::_ldc_w:
485       case Bytecodes::_fast_aldc_w:  // if reverse=true
486         maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
487         break;
488       case Bytecodes::_jsr            : // fall through
489       case Bytecodes::_jsr_w          : nof_jsrs++;                   break;
490       case Bytecodes::_monitorenter   : // fall through
491       case Bytecodes::_monitorexit    : has_monitor_bytecodes = true; break;
492 
493       default: break;
494     }
495   }
496 
497   // Update access flags
498   if (has_monitor_bytecodes) {
499     method->set_has_monitor_bytecodes();
500   }
501 
502   // The present of a jsr bytecode implies that the method might potentially
503   // have to be rewritten, so we run the oopMapGenerator on the method
504   if (nof_jsrs > 0) {
505     method->set_has_jsrs();
506     // Second pass will revisit this method.
507     assert(method->has_jsrs(), "didn't we just set this?");
508   }
509 }
510 
511 // After constant pool is created, revisit methods containing jsrs.
512 methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) {
513   ResourceMark rm(THREAD);
514   ResolveOopMapConflicts romc(method);
515   methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle()));
516   // Update monitor matching info.
517   if (romc.monitor_safe()) {
518     new_method->set_guaranteed_monitor_matching();
519   }
520 
521   return new_method;
522 }
523 
524 void Rewriter::rewrite_bytecodes(TRAPS) {
525   assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
526 
527   // determine index maps for Method* rewriting
528   compute_index_maps();
529 
530   if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
531     bool did_rewrite = false;
532     int i = _methods->length();
533     while (i-- > 0) {
534       Method* method = _methods->at(i);
535       if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
536         // rewrite the return bytecodes of Object.<init> to register the
537         // object for finalization if needed.
538         methodHandle m(THREAD, method);
539         rewrite_Object_init(m, CHECK);
540         did_rewrite = true;
541         break;
542       }
543     }
544     assert(did_rewrite, "must find Object::<init> to rewrite it");
545   }
546 
547   // rewrite methods, in two passes
548   int len = _methods->length();
549   bool invokespecial_error = false;
550 
551   for (int i = len-1; i >= 0; i--) {
552     Method* method = _methods->at(i);
553     scan_method(THREAD, method, false, &invokespecial_error);
554     if (invokespecial_error) {
555       // If you get an error here, there is no reversing bytecodes
556       // This exception is stored for this class and no further attempt is
557       // made at verifying or rewriting.
558       THROW_MSG(vmSymbols::java_lang_InternalError(),
559                 "This classfile overflows invokespecial for interfaces "
560                 "and cannot be loaded");
561       return;
562      }
563   }
564 
565   // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
566   // entries had to be added.
567   patch_invokedynamic_bytecodes();
568 }
569 
570 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) {
571 #if INCLUDE_CDS
572   if (klass->is_shared()) {
573     assert(!klass->is_rewritten(), "rewritten shared classes cannot be rewritten again");
574   }
575 #endif // INCLUDE_CDS
576   ResourceMark rm(THREAD);
577   constantPoolHandle cpool(THREAD, klass->constants());
578   Rewriter     rw(klass, cpool, klass->methods(), CHECK);
579   // (That's all, folks.)
580 }
581 
582 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
583   : _klass(klass),
584     _pool(cpool),
585     _methods(methods),
586     _cp_map(cpool->length()),
587     _cp_cache_map(cpool->length() / 2),
588     _reference_map(cpool->length()),
589     _resolved_references_map(cpool->length() / 2),
590     _invokedynamic_references_map(cpool->length() / 2),
591     _method_handle_invokers(cpool->length()),
592     _invokedynamic_cp_cache_map(cpool->length() / 4)
593 {
594 
595   // Rewrite bytecodes - exception here exits.
596   rewrite_bytecodes(CHECK);
597 
598   // Stress restoring bytecodes
599   if (StressRewriter) {
600     restore_bytecodes(THREAD);
601     rewrite_bytecodes(CHECK);
602   }
603 
604   // allocate constant pool cache, now that we've seen all the bytecodes
605   make_constant_pool_cache(THREAD);
606 
607   // Restore bytecodes to their unrewritten state if there are exceptions
608   // rewriting bytecodes or allocating the cpCache
609   if (HAS_PENDING_EXCEPTION) {
610     restore_bytecodes(THREAD);
611     return;
612   }
613 
614   // Relocate after everything, but still do this under the is_rewritten flag,
615   // so methods with jsrs in custom class lists in aren't attempted to be
616   // rewritten in the RO section of the shared archive.
617   // Relocated bytecodes don't have to be restored, only the cp cache entries
618   int len = _methods->length();
619   for (int i = len-1; i >= 0; i--) {
620     methodHandle m(THREAD, _methods->at(i));
621 
622     if (m->has_jsrs()) {
623       m = rewrite_jsrs(m, THREAD);
624       // Restore bytecodes to their unrewritten state if there are exceptions
625       // relocating bytecodes.  If some are relocated, that is ok because that
626       // doesn't affect constant pool to cpCache rewriting.
627       if (HAS_PENDING_EXCEPTION) {
628         restore_bytecodes(THREAD);
629         return;
630       }
631       // Method might have gotten rewritten.
632       methods->at_put(i, m());
633     }
634   }
635 }