1 /*
   2  * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/shared/gcLocker.hpp"
  27 #include "interpreter/bytecodes.hpp"
  28 #include "interpreter/interpreter.hpp"
  29 #include "interpreter/rewriter.hpp"
  30 #include "memory/metaspaceShared.hpp"
  31 #include "memory/resourceArea.hpp"
  32 #include "oops/generateOopMap.hpp"
  33 #include "prims/methodHandles.hpp"
  34 
  35 // Computes a CPC map (new_index -> original_index) for constant pool entries
  36 // that are referred to by the interpreter at runtime via the constant pool cache.
  37 // Also computes a CP map (original_index -> new_index).
  38 // Marks entries in CP which require additional processing.
  39 void Rewriter::compute_index_maps() {
  40   const int length  = _pool->length();
  41   init_maps(length);
  42   bool saw_mh_symbol = false;
  43   for (int i = 0; i < length; i++) {
  44     int tag = _pool->tag_at(i).value();
  45     switch (tag) {
  46       case JVM_CONSTANT_InterfaceMethodref:
  47       case JVM_CONSTANT_Fieldref          : // fall through
  48       case JVM_CONSTANT_Methodref         : // fall through
  49         add_cp_cache_entry(i);
  50         break;
  51       case JVM_CONSTANT_String:
  52       case JVM_CONSTANT_MethodHandle      : // fall through
  53       case JVM_CONSTANT_MethodType        : // fall through
  54         add_resolved_references_entry(i);
  55         break;
  56       case JVM_CONSTANT_Utf8:
  57         if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
  58             _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
  59           saw_mh_symbol = true;
  60         }
  61         break;
  62     }
  63   }
  64 
  65   // Record limits of resolved reference map for constant pool cache indices
  66   record_map_limits();
  67 
  68   guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
  69             "all cp cache indexes fit in a u2");
  70 
  71   if (saw_mh_symbol) {
  72     _method_handle_invokers.at_grow(length, 0);
  73   }
  74 }
  75 
  76 // Unrewrite the bytecodes if an error occurs.
  77 void Rewriter::restore_bytecodes() {
  78   int len = _methods->length();
  79   bool invokespecial_error = false;
  80 
  81   for (int i = len-1; i >= 0; i--) {
  82     Method* method = _methods->at(i);
  83     scan_method(method, true, &invokespecial_error);
  84     assert(!invokespecial_error, "reversing should not get an invokespecial error");
  85   }
  86 }
  87 
  88 // Creates a constant pool cache given a CPC map
  89 void Rewriter::make_constant_pool_cache(TRAPS) {
  90   ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
  91   ConstantPoolCache* cache =
  92       ConstantPoolCache::allocate(loader_data, _cp_cache_map,
  93                                   _invokedynamic_cp_cache_map,
  94                                   _invokedynamic_references_map, CHECK);
  95 
  96   // initialize object cache in constant pool
  97   _pool->initialize_resolved_references(loader_data, _resolved_references_map,
  98                                         _resolved_reference_limit,
  99                                         CHECK);
 100   _pool->set_cache(cache);
 101   cache->set_constant_pool(_pool());
 102 }
 103 
 104 
 105 
 106 // The new finalization semantics says that registration of
 107 // finalizable objects must be performed on successful return from the
 108 // Object.<init> constructor.  We could implement this trivially if
 109 // <init> were never rewritten but since JVMTI allows this to occur, a
 110 // more complicated solution is required.  A special return bytecode
 111 // is used only by Object.<init> to signal the finalization
 112 // registration point.  Additionally local 0 must be preserved so it's
 113 // available to pass to the registration function.  For simplicity we
 114 // require that local 0 is never overwritten so it's available as an
 115 // argument for registration.
 116 
 117 void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) {
 118   RawBytecodeStream bcs(method);
 119   while (!bcs.is_last_bytecode()) {
 120     Bytecodes::Code opcode = bcs.raw_next();
 121     switch (opcode) {
 122       case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
 123 
 124       case Bytecodes::_istore:
 125       case Bytecodes::_lstore:
 126       case Bytecodes::_fstore:
 127       case Bytecodes::_dstore:
 128       case Bytecodes::_astore:
 129         if (bcs.get_index() != 0) continue;
 130 
 131         // fall through
 132       case Bytecodes::_istore_0:
 133       case Bytecodes::_lstore_0:
 134       case Bytecodes::_fstore_0:
 135       case Bytecodes::_dstore_0:
 136       case Bytecodes::_astore_0:
 137         THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
 138                   "can't overwrite local 0 in Object.<init>");
 139         break;
 140     }
 141   }
 142 }
 143 
 144 
 145 // Rewrite a classfile-order CP index into a native-order CPC index.
 146 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
 147   address p = bcp + offset;
 148   if (!reverse) {
 149     int  cp_index    = Bytes::get_Java_u2(p);
 150     int  cache_index = cp_entry_to_cp_cache(cp_index);
 151     Bytes::put_native_u2(p, cache_index);
 152     if (!_method_handle_invokers.is_empty())
 153       maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
 154   } else {
 155     int cache_index = Bytes::get_native_u2(p);
 156     int pool_index = cp_cache_entry_pool_index(cache_index);
 157     Bytes::put_Java_u2(p, pool_index);
 158     if (!_method_handle_invokers.is_empty())
 159       maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
 160   }
 161 }
 162 
 163 // If the constant pool entry for invokespecial is InterfaceMethodref,
 164 // we need to add a separate cpCache entry for its resolution, because it is
 165 // different than the resolution for invokeinterface with InterfaceMethodref.
 166 // These cannot share cpCache entries.  It's unclear if all invokespecial to
 167 // InterfaceMethodrefs would resolve to the same thing so a new cpCache entry
 168 // is created for each one.  This was added with lambda.
 169 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
 170   address p = bcp + offset;
 171   if (!reverse) {
 172     int cp_index = Bytes::get_Java_u2(p);
 173     if (_pool->tag_at(cp_index).is_interface_method()) {
 174       int cache_index = add_invokespecial_cp_cache_entry(cp_index);
 175       if (cache_index != (int)(jushort) cache_index) {
 176         *invokespecial_error = true;
 177       }
 178       Bytes::put_native_u2(p, cache_index);
 179     } else {
 180       rewrite_member_reference(bcp, offset, reverse);
 181     }
 182   } else {
 183     rewrite_member_reference(bcp, offset, reverse);
 184   }
 185 }
 186 
 187 
 188 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
 189 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
 190   if (!reverse) {
 191     if ((*opc) == (u1)Bytecodes::_invokevirtual ||
 192         // allow invokespecial as an alias, although it would be very odd:
 193         (*opc) == (u1)Bytecodes::_invokespecial) {
 194       assert(_pool->tag_at(cp_index).is_method(), "wrong index");
 195       // Determine whether this is a signature-polymorphic method.
 196       if (cp_index >= _method_handle_invokers.length())  return;
 197       int status = _method_handle_invokers.at(cp_index);
 198       assert(status >= -1 && status <= 1, "oob tri-state");
 199       if (status == 0) {
 200         if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
 201             MethodHandles::is_signature_polymorphic_name(SystemDictionary::MethodHandle_klass(),
 202                                                          _pool->name_ref_at(cp_index))) {
 203           // we may need a resolved_refs entry for the appendix
 204           add_invokedynamic_resolved_references_entries(cp_index, cache_index);
 205           status = +1;
 206         } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
 207                    MethodHandles::is_signature_polymorphic_name(SystemDictionary::VarHandle_klass(),
 208                                                                 _pool->name_ref_at(cp_index))) {
 209           // we may need a resolved_refs entry for the appendix
 210           add_invokedynamic_resolved_references_entries(cp_index, cache_index);
 211           status = +1;
 212         } else {
 213           status = -1;
 214         }
 215         _method_handle_invokers.at(cp_index) = status;
 216       }
 217       // We use a special internal bytecode for such methods (if non-static).
 218       // The basic reason for this is that such methods need an extra "appendix" argument
 219       // to transmit the call site's intended call type.
 220       if (status > 0) {
 221         (*opc) = (u1)Bytecodes::_invokehandle;
 222       }
 223     }
 224   } else {
 225     // Do not need to look at cp_index.
 226     if ((*opc) == (u1)Bytecodes::_invokehandle) {
 227       (*opc) = (u1)Bytecodes::_invokevirtual;
 228       // Ignore corner case of original _invokespecial instruction.
 229       // This is safe because (a) the signature polymorphic method was final, and
 230       // (b) the implementation of MethodHandle will not call invokespecial on it.
 231     }
 232   }
 233 }
 234 
 235 
 236 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
 237   address p = bcp + offset;
 238   assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
 239   if (!reverse) {
 240     int cp_index = Bytes::get_Java_u2(p);
 241     int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
 242     int resolved_index = add_invokedynamic_resolved_references_entries(cp_index, cache_index);
 243     // Replace the trailing four bytes with a CPC index for the dynamic
 244     // call site.  Unlike other CPC entries, there is one per bytecode,
 245     // not just one per distinct CP entry.  In other words, the
 246     // CPC-to-CP relation is many-to-one for invokedynamic entries.
 247     // This means we must use a larger index size than u2 to address
 248     // all these entries.  That is the main reason invokedynamic
 249     // must have a five-byte instruction format.  (Of course, other JVM
 250     // implementations can use the bytes for other purposes.)
 251     // Note: We use native_u4 format exclusively for 4-byte indexes.
 252     Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
 253     // add the bcp in case we need to patch this bytecode if we also find a
 254     // invokespecial/InterfaceMethodref in the bytecode stream
 255     _patch_invokedynamic_bcps->push(p);
 256     _patch_invokedynamic_refs->push(resolved_index);
 257   } else {
 258     int cache_index = ConstantPool::decode_invokedynamic_index(
 259                         Bytes::get_native_u4(p));
 260     // We will reverse the bytecode rewriting _after_ adjusting them.
 261     // Adjust the cache index by offset to the invokedynamic entries in the
 262     // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
 263     int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
 264     int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
 265     assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
 266     // zero out 4 bytes
 267     Bytes::put_Java_u4(p, 0);
 268     Bytes::put_Java_u2(p, cp_index);
 269   }
 270 }
 271 
 272 void Rewriter::patch_invokedynamic_bytecodes() {
 273   // If the end of the cp_cache is the same as after initializing with the
 274   // cpool, nothing needs to be done.  Invokedynamic bytecodes are at the
 275   // correct offsets. ie. no invokespecials added
 276   int delta = cp_cache_delta();
 277   if (delta > 0) {
 278     int length = _patch_invokedynamic_bcps->length();
 279     assert(length == _patch_invokedynamic_refs->length(),
 280            "lengths should match");
 281     for (int i = 0; i < length; i++) {
 282       address p = _patch_invokedynamic_bcps->at(i);
 283       int cache_index = ConstantPool::decode_invokedynamic_index(
 284                           Bytes::get_native_u4(p));
 285       Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
 286 
 287       // invokedynamic resolved references map also points to cp cache and must
 288       // add delta to each.
 289       int resolved_index = _patch_invokedynamic_refs->at(i);
 290       for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
 291         assert(_invokedynamic_references_map.at(resolved_index + entry) == cache_index,
 292              "should be the same index");
 293         _invokedynamic_references_map.at_put(resolved_index+entry,
 294                                              cache_index + delta);
 295       }
 296     }
 297   }
 298 }
 299 
 300 
 301 // Rewrite some ldc bytecodes to _fast_aldc
 302 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
 303                                  bool reverse) {
 304   if (!reverse) {
 305     assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
 306     address p = bcp + offset;
 307     int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
 308     constantTag tag = _pool->tag_at(cp_index).value();
 309     if (tag.is_method_handle() || tag.is_method_type() || tag.is_string()) {
 310       int ref_index = cp_entry_to_resolved_references(cp_index);
 311       if (is_wide) {
 312         (*bcp) = Bytecodes::_fast_aldc_w;
 313         assert(ref_index == (u2)ref_index, "index overflow");
 314         Bytes::put_native_u2(p, ref_index);
 315       } else {
 316         (*bcp) = Bytecodes::_fast_aldc;
 317         assert(ref_index == (u1)ref_index, "index overflow");
 318         (*p) = (u1)ref_index;
 319       }
 320     }
 321   } else {
 322     Bytecodes::Code rewritten_bc =
 323               (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
 324     if ((*bcp) == rewritten_bc) {
 325       address p = bcp + offset;
 326       int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
 327       int pool_index = resolved_references_entry_to_pool_index(ref_index);
 328       if (is_wide) {
 329         (*bcp) = Bytecodes::_ldc_w;
 330         assert(pool_index == (u2)pool_index, "index overflow");
 331         Bytes::put_Java_u2(p, pool_index);
 332       } else {
 333         (*bcp) = Bytecodes::_ldc;
 334         assert(pool_index == (u1)pool_index, "index overflow");
 335         (*p) = (u1)pool_index;
 336       }
 337     }
 338   }
 339 }
 340 
 341 
 342 // Rewrites a method given the index_map information
 343 void Rewriter::scan_method(Method* method, bool reverse, bool* invokespecial_error) {
 344 
 345   int nof_jsrs = 0;
 346   bool has_monitor_bytecodes = false;
 347 
 348   {
 349     // We cannot tolerate a GC in this block, because we've
 350     // cached the bytecodes in 'code_base'. If the Method*
 351     // moves, the bytecodes will also move.
 352     NoSafepointVerifier nsv;
 353     Bytecodes::Code c;
 354 
 355     // Bytecodes and their length
 356     const address code_base = method->code_base();
 357     const int code_length = method->code_size();
 358 
 359     int bc_length;
 360     for (int bci = 0; bci < code_length; bci += bc_length) {
 361       address bcp = code_base + bci;
 362       int prefix_length = 0;
 363       c = (Bytecodes::Code)(*bcp);
 364 
 365       // Since we have the code, see if we can get the length
 366       // directly. Some more complicated bytecodes will report
 367       // a length of zero, meaning we need to make another method
 368       // call to calculate the length.
 369       bc_length = Bytecodes::length_for(c);
 370       if (bc_length == 0) {
 371         bc_length = Bytecodes::length_at(method, bcp);
 372 
 373         // length_at will put us at the bytecode after the one modified
 374         // by 'wide'. We don't currently examine any of the bytecodes
 375         // modified by wide, but in case we do in the future...
 376         if (c == Bytecodes::_wide) {
 377           prefix_length = 1;
 378           c = (Bytecodes::Code)bcp[1];
 379         }
 380       }
 381 
 382       assert(bc_length != 0, "impossible bytecode length");
 383 
 384       switch (c) {
 385         case Bytecodes::_lookupswitch   : {
 386 #ifndef CC_INTERP
 387           Bytecode_lookupswitch bc(method, bcp);
 388           (*bcp) = (
 389             bc.number_of_pairs() < BinarySwitchThreshold
 390             ? Bytecodes::_fast_linearswitch
 391             : Bytecodes::_fast_binaryswitch
 392           );
 393 #endif
 394           break;
 395         }
 396         case Bytecodes::_fast_linearswitch:
 397         case Bytecodes::_fast_binaryswitch: {
 398 #ifndef CC_INTERP
 399           (*bcp) = Bytecodes::_lookupswitch;
 400 #endif
 401           break;
 402         }
 403 
 404         case Bytecodes::_invokespecial  : {
 405           rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
 406           break;
 407         }
 408 
 409         case Bytecodes::_putstatic      :
 410         case Bytecodes::_putfield       : {
 411           if (!reverse) {
 412             // Check if any final field of the class given as parameter is modified
 413             // outside of initializer methods of the class. Fields that are modified
 414             // are marked with a flag. For marked fields, the compilers do not perform
 415             // constant folding (as the field can be changed after initialization).
 416             //
 417             // The check is performed after verification and only if verification has
 418             // succeeded. Therefore, the class is guaranteed to be well-formed.
 419             InstanceKlass* klass = method->method_holder();
 420             u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
 421             constantPoolHandle cp(method->constants());
 422             Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
 423 
 424             if (klass->name() == ref_class_name) {
 425               Symbol* field_name = cp->name_ref_at(bc_index);
 426               Symbol* field_sig = cp->signature_ref_at(bc_index);
 427 
 428               fieldDescriptor fd;
 429               klass->find_field(field_name, field_sig, &fd);
 430               if (fd.access_flags().is_final()) {
 431                 if (fd.access_flags().is_static()) {
 432                   if (!method->is_static_initializer()) {
 433                     fd.set_has_initialized_final_update(true);
 434                   }
 435                 } else {
 436                   if (!method->is_object_initializer()) {
 437                     fd.set_has_initialized_final_update(true);
 438                   }
 439                 }
 440               }
 441             }
 442           }
 443         }
 444         // fall through
 445         case Bytecodes::_getstatic      : // fall through
 446         case Bytecodes::_getfield       : // fall through
 447         case Bytecodes::_invokevirtual  : // fall through
 448         case Bytecodes::_invokestatic   :
 449         case Bytecodes::_invokeinterface:
 450         case Bytecodes::_invokehandle   : // if reverse=true
 451           rewrite_member_reference(bcp, prefix_length+1, reverse);
 452           break;
 453         case Bytecodes::_invokedynamic:
 454           rewrite_invokedynamic(bcp, prefix_length+1, reverse);
 455           break;
 456         case Bytecodes::_ldc:
 457         case Bytecodes::_fast_aldc:  // if reverse=true
 458           maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
 459           break;
 460         case Bytecodes::_ldc_w:
 461         case Bytecodes::_fast_aldc_w:  // if reverse=true
 462           maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
 463           break;
 464         case Bytecodes::_jsr            : // fall through
 465         case Bytecodes::_jsr_w          : nof_jsrs++;                   break;
 466         case Bytecodes::_monitorenter   : // fall through
 467         case Bytecodes::_monitorexit    : has_monitor_bytecodes = true; break;
 468       }
 469     }
 470   }
 471 
 472   // Update access flags
 473   if (has_monitor_bytecodes) {
 474     method->set_has_monitor_bytecodes();
 475   }
 476 
 477   // The present of a jsr bytecode implies that the method might potentially
 478   // have to be rewritten, so we run the oopMapGenerator on the method
 479   if (nof_jsrs > 0) {
 480     method->set_has_jsrs();
 481     // Second pass will revisit this method.
 482     assert(method->has_jsrs(), "didn't we just set this?");
 483   }
 484 }
 485 
 486 // After constant pool is created, revisit methods containing jsrs.
 487 methodHandle Rewriter::rewrite_jsrs(methodHandle method, TRAPS) {
 488   ResourceMark rm(THREAD);
 489   ResolveOopMapConflicts romc(method);
 490   methodHandle original_method = method;
 491   method = romc.do_potential_rewrite(CHECK_(methodHandle()));
 492   // Update monitor matching info.
 493   if (romc.monitor_safe()) {
 494     method->set_guaranteed_monitor_matching();
 495   }
 496 
 497   return method;
 498 }
 499 
 500 void Rewriter::rewrite_bytecodes(TRAPS) {
 501   assert(_pool->cache() == NULL, "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(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   // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
 542   // entries had to be added.
 543   patch_invokedynamic_bytecodes();
 544 }
 545 
 546 void Rewriter::rewrite(instanceKlassHandle klass, TRAPS) {
 547   if (!DumpSharedSpaces) {
 548     assert(!MetaspaceShared::is_in_shared_space(klass()), "archive methods must not be rewritten at run time");
 549   }
 550   ResourceMark rm(THREAD);
 551   Rewriter     rw(klass, klass->constants(), klass->methods(), CHECK);
 552   // (That's all, folks.)
 553 }
 554 
 555 Rewriter::Rewriter(instanceKlassHandle klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
 556   : _klass(klass),
 557     _pool(cpool),
 558     _methods(methods),
 559     _cp_map(cpool->length()),
 560     _cp_cache_map(cpool->length() / 2),
 561     _reference_map(cpool->length()),
 562     _resolved_references_map(cpool->length() / 2),
 563     _invokedynamic_references_map(cpool->length() / 2),
 564     _method_handle_invokers(cpool->length()),
 565     _invokedynamic_cp_cache_map(cpool->length() / 4)
 566 {
 567 
 568   // Rewrite bytecodes - exception here exits.
 569   rewrite_bytecodes(CHECK);
 570 
 571   // Stress restoring bytecodes
 572   if (StressRewriter) {
 573     restore_bytecodes();
 574     rewrite_bytecodes(CHECK);
 575   }
 576 
 577   // allocate constant pool cache, now that we've seen all the bytecodes
 578   make_constant_pool_cache(THREAD);
 579 
 580   // Restore bytecodes to their unrewritten state if there are exceptions
 581   // rewriting bytecodes or allocating the cpCache
 582   if (HAS_PENDING_EXCEPTION) {
 583     restore_bytecodes();
 584     return;
 585   }
 586 
 587   // Relocate after everything, but still do this under the is_rewritten flag,
 588   // so methods with jsrs in custom class lists in aren't attempted to be
 589   // rewritten in the RO section of the shared archive.
 590   // Relocated bytecodes don't have to be restored, only the cp cache entries
 591   int len = _methods->length();
 592   for (int i = len-1; i >= 0; i--) {
 593     methodHandle m(THREAD, _methods->at(i));
 594 
 595     if (m->has_jsrs()) {
 596       m = rewrite_jsrs(m, THREAD);
 597       // Restore bytecodes to their unrewritten state if there are exceptions
 598       // relocating bytecodes.  If some are relocated, that is ok because that
 599       // doesn't affect constant pool to cpCache rewriting.
 600       if (HAS_PENDING_EXCEPTION) {
 601         restore_bytecodes();
 602         return;
 603       }
 604       // Method might have gotten rewritten.
 605       methods->at_put(i, m());
 606     }
 607   }
 608 }