1 /*
   2  * Copyright (c) 1997, 2013, 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 "classfile/classLoaderData.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/metadataOnStackMark.hpp"
  29 #include "classfile/symbolTable.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmSymbols.hpp"
  32 #include "interpreter/linkResolver.hpp"
  33 #include "memory/heapInspection.hpp"
  34 #include "memory/metadataFactory.hpp"
  35 #include "memory/oopFactory.hpp"
  36 #include "oops/constantPool.hpp"
  37 #include "oops/instanceKlass.hpp"
  38 #include "oops/objArrayKlass.hpp"
  39 #include "runtime/fieldType.hpp"
  40 #include "runtime/init.hpp"
  41 #include "runtime/javaCalls.hpp"
  42 #include "runtime/signature.hpp"
  43 #include "runtime/vframe.hpp"
  44 
  45 ConstantPool* ConstantPool::allocate(ClassLoaderData* loader_data, int length, TRAPS) {
  46   // Tags are RW but comment below applies to tags also.
  47   Array<u1>* tags = MetadataFactory::new_writeable_array<u1>(loader_data, length, 0, CHECK_NULL);
  48 
  49   int size = ConstantPool::size(length);
  50 
  51   // CDS considerations:
  52   // Allocate read-write but may be able to move to read-only at dumping time
  53   // if all the klasses are resolved.  The only other field that is writable is
  54   // the resolved_references array, which is recreated at startup time.
  55   // But that could be moved to InstanceKlass (although a pain to access from
  56   // assembly code).  Maybe it could be moved to the cpCache which is RW.
  57   return new (loader_data, size, false, THREAD) ConstantPool(tags);
  58 }
  59 
  60 ConstantPool::ConstantPool(Array<u1>* tags) {
  61   set_length(tags->length());
  62   set_tags(NULL);
  63   set_cache(NULL);
  64   set_reference_map(NULL);
  65   set_resolved_references(NULL);
  66   set_operands(NULL);
  67   set_pool_holder(NULL);
  68   set_flags(0);
  69 
  70   // only set to non-zero if constant pool is merged by RedefineClasses
  71   set_version(0);
  72   set_lock(new Monitor(Monitor::nonleaf + 2, "A constant pool lock"));
  73 
  74   // initialize tag array
  75   int length = tags->length();
  76   for (int index = 0; index < length; index++) {
  77     tags->at_put(index, JVM_CONSTANT_Invalid);
  78   }
  79   set_tags(tags);
  80 }
  81 
  82 void ConstantPool::deallocate_contents(ClassLoaderData* loader_data) {
  83   MetadataFactory::free_metadata(loader_data, cache());
  84   set_cache(NULL);
  85   MetadataFactory::free_array<jushort>(loader_data, operands());
  86   set_operands(NULL);
  87 
  88   release_C_heap_structures();
  89 
  90   // free tag array
  91   MetadataFactory::free_array<u1>(loader_data, tags());
  92   set_tags(NULL);
  93 }
  94 
  95 void ConstantPool::release_C_heap_structures() {
  96   // walk constant pool and decrement symbol reference counts
  97   unreference_symbols();
  98 
  99   delete _lock;
 100   set_lock(NULL);
 101 }
 102 
 103 objArrayOop ConstantPool::resolved_references() const {
 104   return (objArrayOop)JNIHandles::resolve(_resolved_references);
 105 }
 106 
 107 // Create resolved_references array and mapping array for original cp indexes
 108 // The ldc bytecode was rewritten to have the resolved reference array index so need a way
 109 // to map it back for resolving and some unlikely miscellaneous uses.
 110 // The objects created by invokedynamic are appended to this list.
 111 void ConstantPool::initialize_resolved_references(ClassLoaderData* loader_data,
 112                                                   intStack reference_map,
 113                                                   int constant_pool_map_length,
 114                                                    TRAPS) {
 115   // Initialized the resolved object cache.
 116   int map_length = reference_map.length();
 117   if (map_length > 0) {
 118     // Only need mapping back to constant pool entries.  The map isn't used for
 119     // invokedynamic resolved_reference entries.  The constant pool cache index
 120     // has the mapping back to both the constant pool and to the resolved
 121     // reference index.
 122     if (constant_pool_map_length > 0) {
 123       Array<u2>* om = MetadataFactory::new_array<u2>(loader_data, map_length, CHECK);
 124 
 125       for (int i = 0; i < constant_pool_map_length; i++) {
 126         int x = reference_map.at(i);
 127         assert(x == (int)(jushort) x, "klass index is too big");
 128         om->at_put(i, (jushort)x);
 129       }
 130       set_reference_map(om);
 131     }
 132 
 133     // Create Java array for holding resolved strings, methodHandles,
 134     // methodTypes, invokedynamic and invokehandle appendix objects, etc.
 135     objArrayOop stom = oopFactory::new_objArray(SystemDictionary::Object_klass(), map_length, CHECK);
 136     Handle refs_handle (THREAD, (oop)stom);  // must handleize.
 137     set_resolved_references(loader_data->add_handle(refs_handle));
 138   }
 139 }
 140 
 141 // CDS support. Create a new resolved_references array.
 142 void ConstantPool::restore_unshareable_info(TRAPS) {
 143 
 144   // restore the C++ vtable from the shared archive
 145   restore_vtable();
 146 
 147   if (SystemDictionary::Object_klass_loaded()) {
 148     // Recreate the object array and add to ClassLoaderData.
 149     int map_length = resolved_reference_length();
 150     if (map_length > 0) {
 151       objArrayOop stom = oopFactory::new_objArray(SystemDictionary::Object_klass(), map_length, CHECK);
 152       Handle refs_handle (THREAD, (oop)stom);  // must handleize.
 153 
 154       ClassLoaderData* loader_data = pool_holder()->class_loader_data();
 155       set_resolved_references(loader_data->add_handle(refs_handle));
 156     }
 157 
 158     // Also need to recreate the mutex.  Make sure this matches the constructor
 159     set_lock(new Monitor(Monitor::nonleaf + 2, "A constant pool lock"));
 160   }
 161 }
 162 
 163 void ConstantPool::remove_unshareable_info() {
 164   // Resolved references are not in the shared archive.
 165   // Save the length for restoration.  It is not necessarily the same length
 166   // as reference_map.length() if invokedynamic is saved.
 167   set_resolved_reference_length(
 168     resolved_references() != NULL ? resolved_references()->length() : 0);
 169   set_resolved_references(NULL);
 170   set_lock(NULL);
 171 }
 172 
 173 int ConstantPool::cp_to_object_index(int cp_index) {
 174   // this is harder don't do this so much.
 175   for (int i = 0; i< reference_map()->length(); i++) {
 176     if (reference_map()->at(i) == cp_index) return i;
 177     // Zero entry is divider between constant pool indices for strings,
 178     // method handles and method types. After that the index is a constant
 179     // pool cache index for invokedynamic.  Stop when zero (which can never
 180     // be a constant pool index)
 181     if (reference_map()->at(i) == 0) break;
 182   }
 183   // We might not find the index.
 184   return _no_index_sentinel;
 185 }
 186 
 187 Klass* ConstantPool::klass_at_impl(constantPoolHandle this_oop, int which, TRAPS) {
 188   // A resolved constantPool entry will contain a Klass*, otherwise a Symbol*.
 189   // It is not safe to rely on the tag bit's here, since we don't have a lock, and the entry and
 190   // tag is not updated atomicly.
 191 
 192   CPSlot entry = this_oop->slot_at(which);
 193   if (entry.is_resolved()) {
 194     assert(entry.get_klass()->is_klass(), "must be");
 195     // Already resolved - return entry.
 196     return entry.get_klass();
 197   }
 198 
 199   // Acquire lock on constant oop while doing update. After we get the lock, we check if another object
 200   // already has updated the object
 201   assert(THREAD->is_Java_thread(), "must be a Java thread");
 202   bool do_resolve = false;
 203   bool in_error = false;
 204 
 205   // Create a handle for the mirror. This will preserve the resolved class
 206   // until the loader_data is registered.
 207   Handle mirror_handle;
 208 
 209   Symbol* name = NULL;
 210   Handle       loader;
 211   {  MonitorLockerEx ml(this_oop->lock());
 212 
 213     if (this_oop->tag_at(which).is_unresolved_klass()) {
 214       if (this_oop->tag_at(which).is_unresolved_klass_in_error()) {
 215         in_error = true;
 216       } else {
 217         do_resolve = true;
 218         name   = this_oop->unresolved_klass_at(which);
 219         loader = Handle(THREAD, this_oop->pool_holder()->class_loader());
 220       }
 221     }
 222   } // unlocking constantPool
 223 
 224 
 225   // The original attempt to resolve this constant pool entry failed so find the
 226   // original error and throw it again (JVMS 5.4.3).
 227   if (in_error) {
 228     Symbol* error = SystemDictionary::find_resolution_error(this_oop, which);
 229     guarantee(error != (Symbol*)NULL, "tag mismatch with resolution error table");
 230     ResourceMark rm;
 231     // exception text will be the class name
 232     const char* className = this_oop->unresolved_klass_at(which)->as_C_string();
 233     THROW_MSG_0(error, className);
 234   }
 235 
 236   if (do_resolve) {
 237     // this_oop must be unlocked during resolve_or_fail
 238     oop protection_domain = this_oop->pool_holder()->protection_domain();
 239     Handle h_prot (THREAD, protection_domain);
 240     Klass* k_oop = SystemDictionary::resolve_or_fail(name, loader, h_prot, true, THREAD);
 241     KlassHandle k;
 242     if (!HAS_PENDING_EXCEPTION) {
 243       k = KlassHandle(THREAD, k_oop);
 244       // preserve the resolved klass.
 245       mirror_handle = Handle(THREAD, k_oop->java_mirror());
 246       // Do access check for klasses
 247       verify_constant_pool_resolve(this_oop, k, THREAD);
 248     }
 249 
 250     // Failed to resolve class. We must record the errors so that subsequent attempts
 251     // to resolve this constant pool entry fail with the same error (JVMS 5.4.3).
 252     if (HAS_PENDING_EXCEPTION) {
 253       ResourceMark rm;
 254       Symbol* error = PENDING_EXCEPTION->klass()->name();
 255 
 256       bool throw_orig_error = false;
 257       {
 258         MonitorLockerEx ml(this_oop->lock());
 259 
 260         // some other thread has beaten us and has resolved the class.
 261         if (this_oop->tag_at(which).is_klass()) {
 262           CLEAR_PENDING_EXCEPTION;
 263           entry = this_oop->resolved_klass_at(which);
 264           return entry.get_klass();
 265         }
 266 
 267         if (!PENDING_EXCEPTION->
 268               is_a(SystemDictionary::LinkageError_klass())) {
 269           // Just throw the exception and don't prevent these classes from
 270           // being loaded due to virtual machine errors like StackOverflow
 271           // and OutOfMemoryError, etc, or if the thread was hit by stop()
 272           // Needs clarification to section 5.4.3 of the VM spec (see 6308271)
 273         }
 274         else if (!this_oop->tag_at(which).is_unresolved_klass_in_error()) {
 275           SystemDictionary::add_resolution_error(this_oop, which, error);
 276           this_oop->tag_at_put(which, JVM_CONSTANT_UnresolvedClassInError);
 277         } else {
 278           // some other thread has put the class in error state.
 279           error = SystemDictionary::find_resolution_error(this_oop, which);
 280           assert(error != NULL, "checking");
 281           throw_orig_error = true;
 282         }
 283       } // unlocked
 284 
 285       if (throw_orig_error) {
 286         CLEAR_PENDING_EXCEPTION;
 287         ResourceMark rm;
 288         const char* className = this_oop->unresolved_klass_at(which)->as_C_string();
 289         THROW_MSG_0(error, className);
 290       }
 291 
 292       return 0;
 293     }
 294 
 295     if (TraceClassResolution && !k()->oop_is_array()) {
 296       // skip resolving the constant pool so that this code get's
 297       // called the next time some bytecodes refer to this class.
 298       ResourceMark rm;
 299       int line_number = -1;
 300       const char * source_file = NULL;
 301       if (JavaThread::current()->has_last_Java_frame()) {
 302         // try to identify the method which called this function.
 303         vframeStream vfst(JavaThread::current());
 304         if (!vfst.at_end()) {
 305           line_number = vfst.method()->line_number_from_bci(vfst.bci());
 306           Symbol* s = vfst.method()->method_holder()->source_file_name();
 307           if (s != NULL) {
 308             source_file = s->as_C_string();
 309           }
 310         }
 311       }
 312       if (k() != this_oop->pool_holder()) {
 313         // only print something if the classes are different
 314         if (source_file != NULL) {
 315           tty->print("RESOLVE %s %s %s:%d\n",
 316                      this_oop->pool_holder()->external_name(),
 317                      InstanceKlass::cast(k())->external_name(), source_file, line_number);
 318         } else {
 319           tty->print("RESOLVE %s %s\n",
 320                      this_oop->pool_holder()->external_name(),
 321                      InstanceKlass::cast(k())->external_name());
 322         }
 323       }
 324       return k();
 325     } else {
 326       MonitorLockerEx ml(this_oop->lock());
 327       // Only updated constant pool - if it is resolved.
 328       do_resolve = this_oop->tag_at(which).is_unresolved_klass();
 329       if (do_resolve) {
 330         ClassLoaderData* this_key = this_oop->pool_holder()->class_loader_data();
 331         this_key->record_dependency(k(), CHECK_NULL); // Can throw OOM
 332         this_oop->klass_at_put(which, k());
 333       }
 334     }
 335   }
 336 
 337   entry = this_oop->resolved_klass_at(which);
 338   assert(entry.is_resolved() && entry.get_klass()->is_klass(), "must be resolved at this point");
 339   return entry.get_klass();
 340 }
 341 
 342 
 343 // Does not update ConstantPool* - to avoid any exception throwing. Used
 344 // by compiler and exception handling.  Also used to avoid classloads for
 345 // instanceof operations. Returns NULL if the class has not been loaded or
 346 // if the verification of constant pool failed
 347 Klass* ConstantPool::klass_at_if_loaded(constantPoolHandle this_oop, int which) {
 348   CPSlot entry = this_oop->slot_at(which);
 349   if (entry.is_resolved()) {
 350     assert(entry.get_klass()->is_klass(), "must be");
 351     return entry.get_klass();
 352   } else {
 353     assert(entry.is_unresolved(), "must be either symbol or klass");
 354     Thread *thread = Thread::current();
 355     Symbol* name = entry.get_symbol();
 356     oop loader = this_oop->pool_holder()->class_loader();
 357     oop protection_domain = this_oop->pool_holder()->protection_domain();
 358     Handle h_prot (thread, protection_domain);
 359     Handle h_loader (thread, loader);
 360     Klass* k = SystemDictionary::find(name, h_loader, h_prot, thread);
 361 
 362     if (k != NULL) {
 363       // Make sure that resolving is legal
 364       EXCEPTION_MARK;
 365       KlassHandle klass(THREAD, k);
 366       // return NULL if verification fails
 367       verify_constant_pool_resolve(this_oop, klass, THREAD);
 368       if (HAS_PENDING_EXCEPTION) {
 369         CLEAR_PENDING_EXCEPTION;
 370         return NULL;
 371       }
 372       return klass();
 373     } else {
 374       return k;
 375     }
 376   }
 377 }
 378 
 379 
 380 Klass* ConstantPool::klass_ref_at_if_loaded(constantPoolHandle this_oop, int which) {
 381   return klass_at_if_loaded(this_oop, this_oop->klass_ref_index_at(which));
 382 }
 383 
 384 
 385 // This is an interface for the compiler that allows accessing non-resolved entries
 386 // in the constant pool - but still performs the validations tests. Must be used
 387 // in a pre-parse of the compiler - to determine what it can do and not do.
 388 // Note: We cannot update the ConstantPool from the vm_thread.
 389 Klass* ConstantPool::klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int index, TRAPS) {
 390   int which = this_oop->klass_ref_index_at(index);
 391   CPSlot entry = this_oop->slot_at(which);
 392   if (entry.is_resolved()) {
 393     assert(entry.get_klass()->is_klass(), "must be");
 394     return entry.get_klass();
 395   } else {
 396     assert(entry.is_unresolved(), "must be either symbol or klass");
 397     Symbol*  name  = entry.get_symbol();
 398     oop loader = this_oop->pool_holder()->class_loader();
 399     oop protection_domain = this_oop->pool_holder()->protection_domain();
 400     Handle h_loader(THREAD, loader);
 401     Handle h_prot  (THREAD, protection_domain);
 402     KlassHandle k(THREAD, SystemDictionary::find(name, h_loader, h_prot, THREAD));
 403 
 404     // Do access check for klasses
 405     if( k.not_null() ) verify_constant_pool_resolve(this_oop, k, CHECK_NULL);
 406     return k();
 407   }
 408 }
 409 
 410 
 411 Method* ConstantPool::method_at_if_loaded(constantPoolHandle cpool,
 412                                                    int which) {
 413   if (cpool->cache() == NULL)  return NULL;  // nothing to load yet
 414   int cache_index = decode_cpcache_index(which, true);
 415   if (!(cache_index >= 0 && cache_index < cpool->cache()->length())) {
 416     // FIXME: should be an assert
 417     if (PrintMiscellaneous && (Verbose||WizardMode)) {
 418       tty->print_cr("bad operand %d in:", which); cpool->print();
 419     }
 420     return NULL;
 421   }
 422   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 423   return e->method_if_resolved(cpool);
 424 }
 425 
 426 
 427 bool ConstantPool::has_appendix_at_if_loaded(constantPoolHandle cpool, int which) {
 428   if (cpool->cache() == NULL)  return false;  // nothing to load yet
 429   int cache_index = decode_cpcache_index(which, true);
 430   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 431   return e->has_appendix();
 432 }
 433 
 434 oop ConstantPool::appendix_at_if_loaded(constantPoolHandle cpool, int which) {
 435   if (cpool->cache() == NULL)  return NULL;  // nothing to load yet
 436   int cache_index = decode_cpcache_index(which, true);
 437   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 438   return e->appendix_if_resolved(cpool);
 439 }
 440 
 441 
 442 bool ConstantPool::has_method_type_at_if_loaded(constantPoolHandle cpool, int which) {
 443   if (cpool->cache() == NULL)  return false;  // nothing to load yet
 444   int cache_index = decode_cpcache_index(which, true);
 445   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 446   return e->has_method_type();
 447 }
 448 
 449 oop ConstantPool::method_type_at_if_loaded(constantPoolHandle cpool, int which) {
 450   if (cpool->cache() == NULL)  return NULL;  // nothing to load yet
 451   int cache_index = decode_cpcache_index(which, true);
 452   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 453   return e->method_type_if_resolved(cpool);
 454 }
 455 
 456 
 457 Symbol* ConstantPool::impl_name_ref_at(int which, bool uncached) {
 458   int name_index = name_ref_index_at(impl_name_and_type_ref_index_at(which, uncached));
 459   return symbol_at(name_index);
 460 }
 461 
 462 
 463 Symbol* ConstantPool::impl_signature_ref_at(int which, bool uncached) {
 464   int signature_index = signature_ref_index_at(impl_name_and_type_ref_index_at(which, uncached));
 465   return symbol_at(signature_index);
 466 }
 467 
 468 
 469 int ConstantPool::impl_name_and_type_ref_index_at(int which, bool uncached) {
 470   int i = which;
 471   if (!uncached && cache() != NULL) {
 472     if (ConstantPool::is_invokedynamic_index(which)) {
 473       // Invokedynamic index is index into resolved_references
 474       int pool_index = invokedynamic_cp_cache_entry_at(which)->constant_pool_index();
 475       pool_index = invoke_dynamic_name_and_type_ref_index_at(pool_index);
 476       assert(tag_at(pool_index).is_name_and_type(), "");
 477       return pool_index;
 478     }
 479     // change byte-ordering and go via cache
 480     i = remap_instruction_operand_from_cache(which);
 481   } else {
 482     if (tag_at(which).is_invoke_dynamic()) {
 483       int pool_index = invoke_dynamic_name_and_type_ref_index_at(which);
 484       assert(tag_at(pool_index).is_name_and_type(), "");
 485       return pool_index;
 486     }
 487   }
 488   assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");
 489   assert(!tag_at(i).is_invoke_dynamic(), "Must be handled above");
 490   jint ref_index = *int_at_addr(i);
 491   return extract_high_short_from_int(ref_index);
 492 }
 493 
 494 
 495 int ConstantPool::impl_klass_ref_index_at(int which, bool uncached) {
 496   guarantee(!ConstantPool::is_invokedynamic_index(which),
 497             "an invokedynamic instruction does not have a klass");
 498   int i = which;
 499   if (!uncached && cache() != NULL) {
 500     // change byte-ordering and go via cache
 501     i = remap_instruction_operand_from_cache(which);
 502   }
 503   assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");
 504   jint ref_index = *int_at_addr(i);
 505   return extract_low_short_from_int(ref_index);
 506 }
 507 
 508 
 509 
 510 int ConstantPool::remap_instruction_operand_from_cache(int operand) {
 511   int cpc_index = operand;
 512   DEBUG_ONLY(cpc_index -= CPCACHE_INDEX_TAG);
 513   assert((int)(u2)cpc_index == cpc_index, "clean u2");
 514   int member_index = cache()->entry_at(cpc_index)->constant_pool_index();
 515   return member_index;
 516 }
 517 
 518 
 519 void ConstantPool::verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle k, TRAPS) {
 520  if (k->oop_is_instance() || k->oop_is_objArray()) {
 521     instanceKlassHandle holder (THREAD, this_oop->pool_holder());
 522     Klass* elem_oop = k->oop_is_instance() ? k() : ObjArrayKlass::cast(k())->bottom_klass();
 523     KlassHandle element (THREAD, elem_oop);
 524 
 525     // The element type could be a typeArray - we only need the access check if it is
 526     // an reference to another class
 527     if (element->oop_is_instance()) {
 528       LinkResolver::check_klass_accessability(holder, element, CHECK);
 529     }
 530   }
 531 }
 532 
 533 
 534 int ConstantPool::name_ref_index_at(int which_nt) {
 535   jint ref_index = name_and_type_at(which_nt);
 536   return extract_low_short_from_int(ref_index);
 537 }
 538 
 539 
 540 int ConstantPool::signature_ref_index_at(int which_nt) {
 541   jint ref_index = name_and_type_at(which_nt);
 542   return extract_high_short_from_int(ref_index);
 543 }
 544 
 545 
 546 Klass* ConstantPool::klass_ref_at(int which, TRAPS) {
 547   return klass_at(klass_ref_index_at(which), CHECK_NULL);
 548 }
 549 
 550 
 551 Symbol* ConstantPool::klass_name_at(int which) {
 552   assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(),
 553          "Corrupted constant pool");
 554   // A resolved constantPool entry will contain a Klass*, otherwise a Symbol*.
 555   // It is not safe to rely on the tag bit's here, since we don't have a lock, and the entry and
 556   // tag is not updated atomicly.
 557   CPSlot entry = slot_at(which);
 558   if (entry.is_resolved()) {
 559     // Already resolved - return entry's name.
 560     assert(entry.get_klass()->is_klass(), "must be");
 561     return entry.get_klass()->name();
 562   } else {
 563     assert(entry.is_unresolved(), "must be either symbol or klass");
 564     return entry.get_symbol();
 565   }
 566 }
 567 
 568 Symbol* ConstantPool::klass_ref_at_noresolve(int which) {
 569   jint ref_index = klass_ref_index_at(which);
 570   return klass_at_noresolve(ref_index);
 571 }
 572 
 573 Symbol* ConstantPool::uncached_klass_ref_at_noresolve(int which) {
 574   jint ref_index = uncached_klass_ref_index_at(which);
 575   return klass_at_noresolve(ref_index);
 576 }
 577 
 578 char* ConstantPool::string_at_noresolve(int which) {
 579   Symbol* s = unresolved_string_at(which);
 580   if (s == NULL) {
 581     return (char*)"<pseudo-string>";
 582   } else {
 583     return unresolved_string_at(which)->as_C_string();
 584   }
 585 }
 586 
 587 BasicType ConstantPool::basic_type_for_signature_at(int which) {
 588   return FieldType::basic_type(symbol_at(which));
 589 }
 590 
 591 
 592 void ConstantPool::resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS) {
 593   for (int index = 1; index < this_oop->length(); index++) { // Index 0 is unused
 594     if (this_oop->tag_at(index).is_string()) {
 595       this_oop->string_at(index, CHECK);
 596     }
 597   }
 598 }
 599 
 600 // Resolve all the classes in the constant pool.  If they are all resolved,
 601 // the constant pool is read-only.  Enhancement: allocate cp entries to
 602 // another metaspace, and copy to read-only or read-write space if this
 603 // bit is set.
 604 bool ConstantPool::resolve_class_constants(TRAPS) {
 605   constantPoolHandle cp(THREAD, this);
 606   for (int index = 1; index < length(); index++) { // Index 0 is unused
 607     if (tag_at(index).is_unresolved_klass() &&
 608         klass_at_if_loaded(cp, index) == NULL) {
 609       return false;
 610   }
 611   }
 612   // set_preresolution(); or some bit for future use
 613   return true;
 614 }
 615 
 616 // If resolution for MethodHandle or MethodType fails, save the exception
 617 // in the resolution error table, so that the same exception is thrown again.
 618 void ConstantPool::save_and_throw_exception(constantPoolHandle this_oop, int which,
 619                                      int tag, TRAPS) {
 620   ResourceMark rm;
 621   Symbol* error = PENDING_EXCEPTION->klass()->name();
 622   MonitorLockerEx ml(this_oop->lock());  // lock cpool to change tag.
 623 
 624   int error_tag = (tag == JVM_CONSTANT_MethodHandle) ?
 625            JVM_CONSTANT_MethodHandleInError : JVM_CONSTANT_MethodTypeInError;
 626 
 627   if (!PENDING_EXCEPTION->
 628     is_a(SystemDictionary::LinkageError_klass())) {
 629     // Just throw the exception and don't prevent these classes from
 630     // being loaded due to virtual machine errors like StackOverflow
 631     // and OutOfMemoryError, etc, or if the thread was hit by stop()
 632     // Needs clarification to section 5.4.3 of the VM spec (see 6308271)
 633 
 634   } else if (this_oop->tag_at(which).value() != error_tag) {
 635     SystemDictionary::add_resolution_error(this_oop, which, error);
 636     this_oop->tag_at_put(which, error_tag);
 637   } else {
 638     // some other thread has put the class in error state.
 639     error = SystemDictionary::find_resolution_error(this_oop, which);
 640     assert(error != NULL, "checking");
 641     CLEAR_PENDING_EXCEPTION;
 642     THROW_MSG(error, "");
 643   }
 644 }
 645 
 646 
 647 // Called to resolve constants in the constant pool and return an oop.
 648 // Some constant pool entries cache their resolved oop. This is also
 649 // called to create oops from constants to use in arguments for invokedynamic
 650 oop ConstantPool::resolve_constant_at_impl(constantPoolHandle this_oop, int index, int cache_index, TRAPS) {
 651   oop result_oop = NULL;
 652   Handle throw_exception;
 653 
 654   if (cache_index == _possible_index_sentinel) {
 655     // It is possible that this constant is one which is cached in the objects.
 656     // We'll do a linear search.  This should be OK because this usage is rare.
 657     assert(index > 0, "valid index");
 658     cache_index = this_oop->cp_to_object_index(index);
 659   }
 660   assert(cache_index == _no_index_sentinel || cache_index >= 0, "");
 661   assert(index == _no_index_sentinel || index >= 0, "");
 662 
 663   if (cache_index >= 0) {
 664     result_oop = this_oop->resolved_references()->obj_at(cache_index);
 665     if (result_oop != NULL) {
 666       return result_oop;
 667       // That was easy...
 668     }
 669     index = this_oop->object_to_cp_index(cache_index);
 670   }
 671 
 672   jvalue prim_value;  // temp used only in a few cases below
 673 
 674   int tag_value = this_oop->tag_at(index).value();
 675 
 676   switch (tag_value) {
 677 
 678   case JVM_CONSTANT_UnresolvedClass:
 679   case JVM_CONSTANT_UnresolvedClassInError:
 680   case JVM_CONSTANT_Class:
 681     {
 682       assert(cache_index == _no_index_sentinel, "should not have been set");
 683       Klass* resolved = klass_at_impl(this_oop, index, CHECK_NULL);
 684       // ldc wants the java mirror.
 685       result_oop = resolved->java_mirror();
 686       break;
 687     }
 688 
 689   case JVM_CONSTANT_String:
 690     assert(cache_index != _no_index_sentinel, "should have been set");
 691     if (this_oop->is_pseudo_string_at(index)) {
 692       result_oop = this_oop->pseudo_string_at(index, cache_index);
 693       break;
 694     }
 695     result_oop = string_at_impl(this_oop, index, cache_index, CHECK_NULL);
 696     break;
 697 
 698   case JVM_CONSTANT_MethodHandleInError:
 699   case JVM_CONSTANT_MethodTypeInError:
 700     {
 701       Symbol* error = SystemDictionary::find_resolution_error(this_oop, index);
 702       guarantee(error != (Symbol*)NULL, "tag mismatch with resolution error table");
 703       ResourceMark rm;
 704       THROW_MSG_0(error, "");
 705       break;
 706     }
 707 
 708   case JVM_CONSTANT_MethodHandle:
 709     {
 710       int ref_kind                 = this_oop->method_handle_ref_kind_at(index);
 711       int callee_index             = this_oop->method_handle_klass_index_at(index);
 712       Symbol*  name =      this_oop->method_handle_name_ref_at(index);
 713       Symbol*  signature = this_oop->method_handle_signature_ref_at(index);
 714       if (PrintMiscellaneous)
 715         tty->print_cr("resolve JVM_CONSTANT_MethodHandle:%d [%d/%d/%d] %s.%s",
 716                       ref_kind, index, this_oop->method_handle_index_at(index),
 717                       callee_index, name->as_C_string(), signature->as_C_string());
 718       KlassHandle callee;
 719       { Klass* k = klass_at_impl(this_oop, callee_index, CHECK_NULL);
 720         callee = KlassHandle(THREAD, k);
 721       }
 722       KlassHandle klass(THREAD, this_oop->pool_holder());
 723       Handle value = SystemDictionary::link_method_handle_constant(klass, ref_kind,
 724                                                                    callee, name, signature,
 725                                                                    THREAD);
 726       result_oop = value();
 727       if (HAS_PENDING_EXCEPTION) {
 728         save_and_throw_exception(this_oop, index, tag_value, CHECK_NULL);
 729       }
 730       break;
 731     }
 732 
 733   case JVM_CONSTANT_MethodType:
 734     {
 735       Symbol*  signature = this_oop->method_type_signature_at(index);
 736       if (PrintMiscellaneous)
 737         tty->print_cr("resolve JVM_CONSTANT_MethodType [%d/%d] %s",
 738                       index, this_oop->method_type_index_at(index),
 739                       signature->as_C_string());
 740       KlassHandle klass(THREAD, this_oop->pool_holder());
 741       Handle value = SystemDictionary::find_method_handle_type(signature, klass, THREAD);
 742       result_oop = value();
 743       if (HAS_PENDING_EXCEPTION) {
 744         save_and_throw_exception(this_oop, index, tag_value, CHECK_NULL);
 745       }
 746       break;
 747     }
 748 
 749   case JVM_CONSTANT_Integer:
 750     assert(cache_index == _no_index_sentinel, "should not have been set");
 751     prim_value.i = this_oop->int_at(index);
 752     result_oop = java_lang_boxing_object::create(T_INT, &prim_value, CHECK_NULL);
 753     break;
 754 
 755   case JVM_CONSTANT_Float:
 756     assert(cache_index == _no_index_sentinel, "should not have been set");
 757     prim_value.f = this_oop->float_at(index);
 758     result_oop = java_lang_boxing_object::create(T_FLOAT, &prim_value, CHECK_NULL);
 759     break;
 760 
 761   case JVM_CONSTANT_Long:
 762     assert(cache_index == _no_index_sentinel, "should not have been set");
 763     prim_value.j = this_oop->long_at(index);
 764     result_oop = java_lang_boxing_object::create(T_LONG, &prim_value, CHECK_NULL);
 765     break;
 766 
 767   case JVM_CONSTANT_Double:
 768     assert(cache_index == _no_index_sentinel, "should not have been set");
 769     prim_value.d = this_oop->double_at(index);
 770     result_oop = java_lang_boxing_object::create(T_DOUBLE, &prim_value, CHECK_NULL);
 771     break;
 772 
 773   default:
 774     DEBUG_ONLY( tty->print_cr("*** %p: tag at CP[%d/%d] = %d",
 775                               this_oop(), index, cache_index, tag_value) );
 776     assert(false, "unexpected constant tag");
 777     break;
 778   }
 779 
 780   if (cache_index >= 0) {
 781     // Cache the oop here also.
 782     Handle result_handle(THREAD, result_oop);
 783     MonitorLockerEx ml(this_oop->lock());  // don't know if we really need this
 784     oop result = this_oop->resolved_references()->obj_at(cache_index);
 785     // Benign race condition:  resolved_references may already be filled in while we were trying to lock.
 786     // The important thing here is that all threads pick up the same result.
 787     // It doesn't matter which racing thread wins, as long as only one
 788     // result is used by all threads, and all future queries.
 789     // That result may be either a resolved constant or a failure exception.
 790     if (result == NULL) {
 791       this_oop->resolved_references()->obj_at_put(cache_index, result_handle());
 792       return result_handle();
 793     } else {
 794       // Return the winning thread's result.  This can be different than
 795       // result_handle() for MethodHandles.
 796       return result;
 797     }
 798   } else {
 799     return result_oop;
 800   }
 801 }
 802 
 803 oop ConstantPool::uncached_string_at(int which, TRAPS) {
 804   Symbol* sym = unresolved_string_at(which);
 805   oop str = StringTable::intern(sym, CHECK_(NULL));
 806   assert(java_lang_String::is_instance(str), "must be string");
 807   return str;
 808 }
 809 
 810 
 811 oop ConstantPool::resolve_bootstrap_specifier_at_impl(constantPoolHandle this_oop, int index, TRAPS) {
 812   assert(this_oop->tag_at(index).is_invoke_dynamic(), "Corrupted constant pool");
 813 
 814   Handle bsm;
 815   int argc;
 816   {
 817     // JVM_CONSTANT_InvokeDynamic is an ordered pair of [bootm, name&type], plus optional arguments
 818     // The bootm, being a JVM_CONSTANT_MethodHandle, has its own cache entry.
 819     // It is accompanied by the optional arguments.
 820     int bsm_index = this_oop->invoke_dynamic_bootstrap_method_ref_index_at(index);
 821     oop bsm_oop = this_oop->resolve_possibly_cached_constant_at(bsm_index, CHECK_NULL);
 822     if (!java_lang_invoke_MethodHandle::is_instance(bsm_oop)) {
 823       THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "BSM not an MethodHandle");
 824     }
 825 
 826     // Extract the optional static arguments.
 827     argc = this_oop->invoke_dynamic_argument_count_at(index);
 828     if (argc == 0)  return bsm_oop;
 829 
 830     bsm = Handle(THREAD, bsm_oop);
 831   }
 832 
 833   objArrayHandle info;
 834   {
 835     objArrayOop info_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1+argc, CHECK_NULL);
 836     info = objArrayHandle(THREAD, info_oop);
 837   }
 838 
 839   info->obj_at_put(0, bsm());
 840   for (int i = 0; i < argc; i++) {
 841     int arg_index = this_oop->invoke_dynamic_argument_index_at(index, i);
 842     oop arg_oop = this_oop->resolve_possibly_cached_constant_at(arg_index, CHECK_NULL);
 843     info->obj_at_put(1+i, arg_oop);
 844   }
 845 
 846   return info();
 847 }
 848 
 849 oop ConstantPool::string_at_impl(constantPoolHandle this_oop, int which, int obj_index, TRAPS) {
 850   // If the string has already been interned, this entry will be non-null
 851   oop str = this_oop->resolved_references()->obj_at(obj_index);
 852   if (str != NULL) return str;
 853 
 854       Symbol* sym = this_oop->unresolved_string_at(which);
 855   str = StringTable::intern(sym, CHECK_(NULL));
 856   this_oop->string_at_put(which, obj_index, str);
 857   assert(java_lang_String::is_instance(str), "must be string");
 858   return str;
 859 }
 860 
 861 
 862 bool ConstantPool::klass_name_at_matches(instanceKlassHandle k,
 863                                                 int which) {
 864   // Names are interned, so we can compare Symbol*s directly
 865   Symbol* cp_name = klass_name_at(which);
 866   return (cp_name == k->name());
 867 }
 868 
 869 
 870 // Iterate over symbols and decrement ones which are Symbol*s.
 871 // This is done during GC so do not need to lock constantPool unless we
 872 // have per-thread safepoints.
 873 // Only decrement the UTF8 symbols. Unresolved classes and strings point to
 874 // these symbols but didn't increment the reference count.
 875 void ConstantPool::unreference_symbols() {
 876   for (int index = 1; index < length(); index++) { // Index 0 is unused
 877     constantTag tag = tag_at(index);
 878     if (tag.is_symbol()) {
 879       symbol_at(index)->decrement_refcount();
 880     }
 881   }
 882 }
 883 
 884 
 885 // Compare this constant pool's entry at index1 to the constant pool
 886 // cp2's entry at index2.
 887 bool ConstantPool::compare_entry_to(int index1, constantPoolHandle cp2,
 888        int index2, TRAPS) {
 889 
 890   jbyte t1 = tag_at(index1).value();
 891   jbyte t2 = cp2->tag_at(index2).value();
 892 
 893 
 894   // JVM_CONSTANT_UnresolvedClassInError is equal to JVM_CONSTANT_UnresolvedClass
 895   // when comparing
 896   if (t1 == JVM_CONSTANT_UnresolvedClassInError) {
 897     t1 = JVM_CONSTANT_UnresolvedClass;
 898   }
 899   if (t2 == JVM_CONSTANT_UnresolvedClassInError) {
 900     t2 = JVM_CONSTANT_UnresolvedClass;
 901   }
 902 
 903   if (t1 != t2) {
 904     // Not the same entry type so there is nothing else to check. Note
 905     // that this style of checking will consider resolved/unresolved
 906     // class pairs as different.
 907     // From the ConstantPool* API point of view, this is correct
 908     // behavior. See VM_RedefineClasses::merge_constant_pools() to see how this
 909     // plays out in the context of ConstantPool* merging.
 910     return false;
 911   }
 912 
 913   switch (t1) {
 914   case JVM_CONSTANT_Class:
 915   {
 916     Klass* k1 = klass_at(index1, CHECK_false);
 917     Klass* k2 = cp2->klass_at(index2, CHECK_false);
 918     if (k1 == k2) {
 919       return true;
 920     }
 921   } break;
 922 
 923   case JVM_CONSTANT_ClassIndex:
 924   {
 925     int recur1 = klass_index_at(index1);
 926     int recur2 = cp2->klass_index_at(index2);
 927     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
 928     if (match) {
 929       return true;
 930     }
 931   } break;
 932 
 933   case JVM_CONSTANT_Double:
 934   {
 935     jdouble d1 = double_at(index1);
 936     jdouble d2 = cp2->double_at(index2);
 937     if (d1 == d2) {
 938       return true;
 939     }
 940   } break;
 941 
 942   case JVM_CONSTANT_Fieldref:
 943   case JVM_CONSTANT_InterfaceMethodref:
 944   case JVM_CONSTANT_Methodref:
 945   {
 946     int recur1 = uncached_klass_ref_index_at(index1);
 947     int recur2 = cp2->uncached_klass_ref_index_at(index2);
 948     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
 949     if (match) {
 950       recur1 = uncached_name_and_type_ref_index_at(index1);
 951       recur2 = cp2->uncached_name_and_type_ref_index_at(index2);
 952       match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
 953       if (match) {
 954         return true;
 955       }
 956     }
 957   } break;
 958 
 959   case JVM_CONSTANT_Float:
 960   {
 961     jfloat f1 = float_at(index1);
 962     jfloat f2 = cp2->float_at(index2);
 963     if (f1 == f2) {
 964       return true;
 965     }
 966   } break;
 967 
 968   case JVM_CONSTANT_Integer:
 969   {
 970     jint i1 = int_at(index1);
 971     jint i2 = cp2->int_at(index2);
 972     if (i1 == i2) {
 973       return true;
 974     }
 975   } break;
 976 
 977   case JVM_CONSTANT_Long:
 978   {
 979     jlong l1 = long_at(index1);
 980     jlong l2 = cp2->long_at(index2);
 981     if (l1 == l2) {
 982       return true;
 983     }
 984   } break;
 985 
 986   case JVM_CONSTANT_NameAndType:
 987   {
 988     int recur1 = name_ref_index_at(index1);
 989     int recur2 = cp2->name_ref_index_at(index2);
 990     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
 991     if (match) {
 992       recur1 = signature_ref_index_at(index1);
 993       recur2 = cp2->signature_ref_index_at(index2);
 994       match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
 995       if (match) {
 996         return true;
 997       }
 998     }
 999   } break;
1000 
1001   case JVM_CONSTANT_StringIndex:
1002   {
1003     int recur1 = string_index_at(index1);
1004     int recur2 = cp2->string_index_at(index2);
1005     bool match = compare_entry_to(recur1, cp2, recur2, CHECK_false);
1006     if (match) {
1007       return true;
1008     }
1009   } break;
1010 
1011   case JVM_CONSTANT_UnresolvedClass:
1012   {
1013     Symbol* k1 = unresolved_klass_at(index1);
1014     Symbol* k2 = cp2->unresolved_klass_at(index2);
1015     if (k1 == k2) {
1016       return true;
1017     }
1018   } break;
1019 
1020   case JVM_CONSTANT_MethodType:
1021   {
1022     int k1 = method_type_index_at(index1);
1023     int k2 = cp2->method_type_index_at(index2);
1024     bool match = compare_entry_to(k1, cp2, k2, CHECK_false);
1025     if (match) {
1026       return true;
1027     }
1028   } break;
1029 
1030   case JVM_CONSTANT_MethodHandle:
1031   {
1032     int k1 = method_handle_ref_kind_at(index1);
1033     int k2 = cp2->method_handle_ref_kind_at(index2);
1034     if (k1 == k2) {
1035       int i1 = method_handle_index_at(index1);
1036       int i2 = cp2->method_handle_index_at(index2);
1037       bool match = compare_entry_to(i1, cp2, i2, CHECK_false);
1038       if (match) {
1039         return true;
1040       }
1041     }
1042   } break;
1043 
1044   case JVM_CONSTANT_InvokeDynamic:
1045   {
1046     int k1 = invoke_dynamic_bootstrap_method_ref_index_at(index1);
1047     int k2 = cp2->invoke_dynamic_bootstrap_method_ref_index_at(index2);
1048     bool match = compare_entry_to(k1, cp2, k2, CHECK_false);
1049     if (!match)  return false;
1050     k1 = invoke_dynamic_name_and_type_ref_index_at(index1);
1051     k2 = cp2->invoke_dynamic_name_and_type_ref_index_at(index2);
1052     match = compare_entry_to(k1, cp2, k2, CHECK_false);
1053     if (!match)  return false;
1054     int argc = invoke_dynamic_argument_count_at(index1);
1055     if (argc == cp2->invoke_dynamic_argument_count_at(index2)) {
1056       for (int j = 0; j < argc; j++) {
1057         k1 = invoke_dynamic_argument_index_at(index1, j);
1058         k2 = cp2->invoke_dynamic_argument_index_at(index2, j);
1059         match = compare_entry_to(k1, cp2, k2, CHECK_false);
1060         if (!match)  return false;
1061       }
1062       return true;           // got through loop; all elements equal
1063     }
1064   } break;
1065 
1066   case JVM_CONSTANT_String:
1067   {
1068     Symbol* s1 = unresolved_string_at(index1);
1069     Symbol* s2 = cp2->unresolved_string_at(index2);
1070     if (s1 == s2) {
1071       return true;
1072     }
1073   } break;
1074 
1075   case JVM_CONSTANT_Utf8:
1076   {
1077     Symbol* s1 = symbol_at(index1);
1078     Symbol* s2 = cp2->symbol_at(index2);
1079     if (s1 == s2) {
1080       return true;
1081     }
1082   } break;
1083 
1084   // Invalid is used as the tag for the second constant pool entry
1085   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
1086   // not be seen by itself.
1087   case JVM_CONSTANT_Invalid: // fall through
1088 
1089   default:
1090     ShouldNotReachHere();
1091     break;
1092   }
1093 
1094   return false;
1095 } // end compare_entry_to()
1096 
1097 
1098 void ConstantPool::copy_operands(constantPoolHandle from_cp,
1099                                  constantPoolHandle to_cp,
1100                                  TRAPS) {
1101 
1102   int from_oplen = operand_array_length(from_cp->operands());
1103   int old_oplen  = operand_array_length(to_cp->operands());
1104   if (from_oplen != 0) {
1105     ClassLoaderData* loader_data = to_cp->pool_holder()->class_loader_data();
1106     // append my operands to the target's operands array
1107     if (old_oplen == 0) {
1108       // Can't just reuse from_cp's operand list because of deallocation issues
1109       int len = from_cp->operands()->length();
1110       Array<u2>* new_ops = MetadataFactory::new_array<u2>(loader_data, len, CHECK);
1111       Copy::conjoint_memory_atomic(
1112           from_cp->operands()->adr_at(0), new_ops->adr_at(0), len * sizeof(u2));
1113       to_cp->set_operands(new_ops);
1114     } else {
1115       int old_len  = to_cp->operands()->length();
1116       int from_len = from_cp->operands()->length();
1117       int old_off  = old_oplen * sizeof(u2);
1118       int from_off = from_oplen * sizeof(u2);
1119       // Use the metaspace for the destination constant pool
1120       Array<u2>* new_operands = MetadataFactory::new_array<u2>(loader_data, old_len + from_len, CHECK);
1121       int fillp = 0, len = 0;
1122       // first part of dest
1123       Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(0),
1124                                    new_operands->adr_at(fillp),
1125                                    (len = old_off) * sizeof(u2));
1126       fillp += len;
1127       // first part of src
1128       Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(0),
1129                                    new_operands->adr_at(fillp),
1130                                    (len = from_off) * sizeof(u2));
1131       fillp += len;
1132       // second part of dest
1133       Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(old_off),
1134                                    new_operands->adr_at(fillp),
1135                                    (len = old_len - old_off) * sizeof(u2));
1136       fillp += len;
1137       // second part of src
1138       Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(from_off),
1139                                    new_operands->adr_at(fillp),
1140                                    (len = from_len - from_off) * sizeof(u2));
1141       fillp += len;
1142       assert(fillp == new_operands->length(), "");
1143 
1144       // Adjust indexes in the first part of the copied operands array.
1145       for (int j = 0; j < from_oplen; j++) {
1146         int offset = operand_offset_at(new_operands, old_oplen + j);
1147         assert(offset == operand_offset_at(from_cp->operands(), j), "correct copy");
1148         offset += old_len;  // every new tuple is preceded by old_len extra u2's
1149         operand_offset_at_put(new_operands, old_oplen + j, offset);
1150       }
1151 
1152       // replace target operands array with combined array
1153       to_cp->set_operands(new_operands);
1154     }
1155   }
1156 } // end copy_operands()
1157 
1158 
1159 // Copy this constant pool's entries at start_i to end_i (inclusive)
1160 // to the constant pool to_cp's entries starting at to_i. A total of
1161 // (end_i - start_i) + 1 entries are copied.
1162 void ConstantPool::copy_cp_to_impl(constantPoolHandle from_cp, int start_i, int end_i,
1163        constantPoolHandle to_cp, int to_i, TRAPS) {
1164 
1165 
1166   int dest_i = to_i;  // leave original alone for debug purposes
1167 
1168   for (int src_i = start_i; src_i <= end_i; /* see loop bottom */ ) {
1169     copy_entry_to(from_cp, src_i, to_cp, dest_i, CHECK);
1170 
1171     switch (from_cp->tag_at(src_i).value()) {
1172     case JVM_CONSTANT_Double:
1173     case JVM_CONSTANT_Long:
1174       // double and long take two constant pool entries
1175       src_i += 2;
1176       dest_i += 2;
1177       break;
1178 
1179     default:
1180       // all others take one constant pool entry
1181       src_i++;
1182       dest_i++;
1183       break;
1184     }
1185   }
1186   copy_operands(from_cp, to_cp, CHECK);
1187 
1188 } // end copy_cp_to_impl()
1189 
1190 
1191 // Copy this constant pool's entry at from_i to the constant pool
1192 // to_cp's entry at to_i.
1193 void ConstantPool::copy_entry_to(constantPoolHandle from_cp, int from_i,
1194                                         constantPoolHandle to_cp, int to_i,
1195                                         TRAPS) {
1196 
1197   int tag = from_cp->tag_at(from_i).value();
1198   switch (tag) {
1199   case JVM_CONSTANT_Class:
1200   {
1201     Klass* k = from_cp->klass_at(from_i, CHECK);
1202     to_cp->klass_at_put(to_i, k);
1203   } break;
1204 
1205   case JVM_CONSTANT_ClassIndex:
1206   {
1207     jint ki = from_cp->klass_index_at(from_i);
1208     to_cp->klass_index_at_put(to_i, ki);
1209   } break;
1210 
1211   case JVM_CONSTANT_Double:
1212   {
1213     jdouble d = from_cp->double_at(from_i);
1214     to_cp->double_at_put(to_i, d);
1215     // double takes two constant pool entries so init second entry's tag
1216     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);
1217   } break;
1218 
1219   case JVM_CONSTANT_Fieldref:
1220   {
1221     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1222     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1223     to_cp->field_at_put(to_i, class_index, name_and_type_index);
1224   } break;
1225 
1226   case JVM_CONSTANT_Float:
1227   {
1228     jfloat f = from_cp->float_at(from_i);
1229     to_cp->float_at_put(to_i, f);
1230   } break;
1231 
1232   case JVM_CONSTANT_Integer:
1233   {
1234     jint i = from_cp->int_at(from_i);
1235     to_cp->int_at_put(to_i, i);
1236   } break;
1237 
1238   case JVM_CONSTANT_InterfaceMethodref:
1239   {
1240     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1241     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1242     to_cp->interface_method_at_put(to_i, class_index, name_and_type_index);
1243   } break;
1244 
1245   case JVM_CONSTANT_Long:
1246   {
1247     jlong l = from_cp->long_at(from_i);
1248     to_cp->long_at_put(to_i, l);
1249     // long takes two constant pool entries so init second entry's tag
1250     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);
1251   } break;
1252 
1253   case JVM_CONSTANT_Methodref:
1254   {
1255     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1256     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1257     to_cp->method_at_put(to_i, class_index, name_and_type_index);
1258   } break;
1259 
1260   case JVM_CONSTANT_NameAndType:
1261   {
1262     int name_ref_index = from_cp->name_ref_index_at(from_i);
1263     int signature_ref_index = from_cp->signature_ref_index_at(from_i);
1264     to_cp->name_and_type_at_put(to_i, name_ref_index, signature_ref_index);
1265   } break;
1266 
1267   case JVM_CONSTANT_StringIndex:
1268   {
1269     jint si = from_cp->string_index_at(from_i);
1270     to_cp->string_index_at_put(to_i, si);
1271   } break;
1272 
1273   case JVM_CONSTANT_UnresolvedClass:
1274   {
1275     // Can be resolved after checking tag, so check the slot first.
1276     CPSlot entry = from_cp->slot_at(from_i);
1277     if (entry.is_resolved()) {
1278       assert(entry.get_klass()->is_klass(), "must be");
1279       // Already resolved
1280       to_cp->klass_at_put(to_i, entry.get_klass());
1281     } else {
1282       to_cp->unresolved_klass_at_put(to_i, entry.get_symbol());
1283     }
1284   } break;
1285 
1286   case JVM_CONSTANT_UnresolvedClassInError:
1287   {
1288     Symbol* k = from_cp->unresolved_klass_at(from_i);
1289     to_cp->unresolved_klass_at_put(to_i, k);
1290     to_cp->tag_at_put(to_i, JVM_CONSTANT_UnresolvedClassInError);
1291   } break;
1292 
1293 
1294   case JVM_CONSTANT_String:
1295   {
1296     Symbol* s = from_cp->unresolved_string_at(from_i);
1297     to_cp->unresolved_string_at_put(to_i, s);
1298   } break;
1299 
1300   case JVM_CONSTANT_Utf8:
1301   {
1302     Symbol* s = from_cp->symbol_at(from_i);
1303     // Need to increase refcount, the old one will be thrown away and deferenced
1304     s->increment_refcount();
1305     to_cp->symbol_at_put(to_i, s);
1306   } break;
1307 
1308   case JVM_CONSTANT_MethodType:
1309   {
1310     jint k = from_cp->method_type_index_at(from_i);
1311     to_cp->method_type_index_at_put(to_i, k);
1312   } break;
1313 
1314   case JVM_CONSTANT_MethodHandle:
1315   {
1316     int k1 = from_cp->method_handle_ref_kind_at(from_i);
1317     int k2 = from_cp->method_handle_index_at(from_i);
1318     to_cp->method_handle_index_at_put(to_i, k1, k2);
1319   } break;
1320 
1321   case JVM_CONSTANT_InvokeDynamic:
1322   {
1323     int k1 = from_cp->invoke_dynamic_bootstrap_specifier_index(from_i);
1324     int k2 = from_cp->invoke_dynamic_name_and_type_ref_index_at(from_i);
1325     k1 += operand_array_length(to_cp->operands());  // to_cp might already have operands
1326     to_cp->invoke_dynamic_at_put(to_i, k1, k2);
1327   } break;
1328 
1329   // Invalid is used as the tag for the second constant pool entry
1330   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
1331   // not be seen by itself.
1332   case JVM_CONSTANT_Invalid: // fall through
1333 
1334   default:
1335   {
1336     ShouldNotReachHere();
1337   } break;
1338   }
1339 } // end copy_entry_to()
1340 
1341 
1342 // Search constant pool search_cp for an entry that matches this
1343 // constant pool's entry at pattern_i. Returns the index of a
1344 // matching entry or zero (0) if there is no matching entry.
1345 int ConstantPool::find_matching_entry(int pattern_i,
1346       constantPoolHandle search_cp, TRAPS) {
1347 
1348   // index zero (0) is not used
1349   for (int i = 1; i < search_cp->length(); i++) {
1350     bool found = compare_entry_to(pattern_i, search_cp, i, CHECK_0);
1351     if (found) {
1352       return i;
1353     }
1354   }
1355 
1356   return 0;  // entry not found; return unused index zero (0)
1357 } // end find_matching_entry()
1358 
1359 
1360 #ifndef PRODUCT
1361 
1362 const char* ConstantPool::printable_name_at(int which) {
1363 
1364   constantTag tag = tag_at(which);
1365 
1366   if (tag.is_string()) {
1367     return string_at_noresolve(which);
1368   } else if (tag.is_klass() || tag.is_unresolved_klass()) {
1369     return klass_name_at(which)->as_C_string();
1370   } else if (tag.is_symbol()) {
1371     return symbol_at(which)->as_C_string();
1372   }
1373   return "";
1374 }
1375 
1376 #endif // PRODUCT
1377 
1378 
1379 // JVMTI GetConstantPool support
1380 
1381 // For temporary use until code is stable.
1382 #define DBG(code)
1383 
1384 static const char* WARN_MSG = "Must not be such entry!";
1385 
1386 static void print_cpool_bytes(jint cnt, u1 *bytes) {
1387   jint size = 0;
1388   u2   idx1, idx2;
1389 
1390   for (jint idx = 1; idx < cnt; idx++) {
1391     jint ent_size = 0;
1392     u1   tag  = *bytes++;
1393     size++;                       // count tag
1394 
1395     printf("const #%03d, tag: %02d ", idx, tag);
1396     switch(tag) {
1397       case JVM_CONSTANT_Invalid: {
1398         printf("Invalid");
1399         break;
1400       }
1401       case JVM_CONSTANT_Unicode: {
1402         printf("Unicode      %s", WARN_MSG);
1403         break;
1404       }
1405       case JVM_CONSTANT_Utf8: {
1406         u2 len = Bytes::get_Java_u2(bytes);
1407         char str[128];
1408         if (len > 127) {
1409            len = 127;
1410         }
1411         strncpy(str, (char *) (bytes+2), len);
1412         str[len] = '\0';
1413         printf("Utf8          \"%s\"", str);
1414         ent_size = 2 + len;
1415         break;
1416       }
1417       case JVM_CONSTANT_Integer: {
1418         u4 val = Bytes::get_Java_u4(bytes);
1419         printf("int          %d", *(int *) &val);
1420         ent_size = 4;
1421         break;
1422       }
1423       case JVM_CONSTANT_Float: {
1424         u4 val = Bytes::get_Java_u4(bytes);
1425         printf("float        %5.3ff", *(float *) &val);
1426         ent_size = 4;
1427         break;
1428       }
1429       case JVM_CONSTANT_Long: {
1430         u8 val = Bytes::get_Java_u8(bytes);
1431         printf("long         "INT64_FORMAT, (int64_t) *(jlong *) &val);
1432         ent_size = 8;
1433         idx++; // Long takes two cpool slots
1434         break;
1435       }
1436       case JVM_CONSTANT_Double: {
1437         u8 val = Bytes::get_Java_u8(bytes);
1438         printf("double       %5.3fd", *(jdouble *)&val);
1439         ent_size = 8;
1440         idx++; // Double takes two cpool slots
1441         break;
1442       }
1443       case JVM_CONSTANT_Class: {
1444         idx1 = Bytes::get_Java_u2(bytes);
1445         printf("class        #%03d", idx1);
1446         ent_size = 2;
1447         break;
1448       }
1449       case JVM_CONSTANT_String: {
1450         idx1 = Bytes::get_Java_u2(bytes);
1451         printf("String       #%03d", idx1);
1452         ent_size = 2;
1453         break;
1454       }
1455       case JVM_CONSTANT_Fieldref: {
1456         idx1 = Bytes::get_Java_u2(bytes);
1457         idx2 = Bytes::get_Java_u2(bytes+2);
1458         printf("Field        #%03d, #%03d", (int) idx1, (int) idx2);
1459         ent_size = 4;
1460         break;
1461       }
1462       case JVM_CONSTANT_Methodref: {
1463         idx1 = Bytes::get_Java_u2(bytes);
1464         idx2 = Bytes::get_Java_u2(bytes+2);
1465         printf("Method       #%03d, #%03d", idx1, idx2);
1466         ent_size = 4;
1467         break;
1468       }
1469       case JVM_CONSTANT_InterfaceMethodref: {
1470         idx1 = Bytes::get_Java_u2(bytes);
1471         idx2 = Bytes::get_Java_u2(bytes+2);
1472         printf("InterfMethod #%03d, #%03d", idx1, idx2);
1473         ent_size = 4;
1474         break;
1475       }
1476       case JVM_CONSTANT_NameAndType: {
1477         idx1 = Bytes::get_Java_u2(bytes);
1478         idx2 = Bytes::get_Java_u2(bytes+2);
1479         printf("NameAndType  #%03d, #%03d", idx1, idx2);
1480         ent_size = 4;
1481         break;
1482       }
1483       case JVM_CONSTANT_ClassIndex: {
1484         printf("ClassIndex  %s", WARN_MSG);
1485         break;
1486       }
1487       case JVM_CONSTANT_UnresolvedClass: {
1488         printf("UnresolvedClass: %s", WARN_MSG);
1489         break;
1490       }
1491       case JVM_CONSTANT_UnresolvedClassInError: {
1492         printf("UnresolvedClassInErr: %s", WARN_MSG);
1493         break;
1494       }
1495       case JVM_CONSTANT_StringIndex: {
1496         printf("StringIndex: %s", WARN_MSG);
1497         break;
1498       }
1499     }
1500     printf(";\n");
1501     bytes += ent_size;
1502     size  += ent_size;
1503   }
1504   printf("Cpool size: %d\n", size);
1505   fflush(0);
1506   return;
1507 } /* end print_cpool_bytes */
1508 
1509 
1510 // Returns size of constant pool entry.
1511 jint ConstantPool::cpool_entry_size(jint idx) {
1512   switch(tag_at(idx).value()) {
1513     case JVM_CONSTANT_Invalid:
1514     case JVM_CONSTANT_Unicode:
1515       return 1;
1516 
1517     case JVM_CONSTANT_Utf8:
1518       return 3 + symbol_at(idx)->utf8_length();
1519 
1520     case JVM_CONSTANT_Class:
1521     case JVM_CONSTANT_String:
1522     case JVM_CONSTANT_ClassIndex:
1523     case JVM_CONSTANT_UnresolvedClass:
1524     case JVM_CONSTANT_UnresolvedClassInError:
1525     case JVM_CONSTANT_StringIndex:
1526     case JVM_CONSTANT_MethodType:
1527       return 3;
1528 
1529     case JVM_CONSTANT_MethodHandle:
1530       return 4; //tag, ref_kind, ref_index
1531 
1532     case JVM_CONSTANT_Integer:
1533     case JVM_CONSTANT_Float:
1534     case JVM_CONSTANT_Fieldref:
1535     case JVM_CONSTANT_Methodref:
1536     case JVM_CONSTANT_InterfaceMethodref:
1537     case JVM_CONSTANT_NameAndType:
1538       return 5;
1539 
1540     case JVM_CONSTANT_InvokeDynamic:
1541       // u1 tag, u2 bsm, u2 nt
1542       return 5;
1543 
1544     case JVM_CONSTANT_Long:
1545     case JVM_CONSTANT_Double:
1546       return 9;
1547   }
1548   assert(false, "cpool_entry_size: Invalid constant pool entry tag");
1549   return 1;
1550 } /* end cpool_entry_size */
1551 
1552 
1553 // SymbolHashMap is used to find a constant pool index from a string.
1554 // This function fills in SymbolHashMaps, one for utf8s and one for
1555 // class names, returns size of the cpool raw bytes.
1556 jint ConstantPool::hash_entries_to(SymbolHashMap *symmap,
1557                                           SymbolHashMap *classmap) {
1558   jint size = 0;
1559 
1560   for (u2 idx = 1; idx < length(); idx++) {
1561     u2 tag = tag_at(idx).value();
1562     size += cpool_entry_size(idx);
1563 
1564     switch(tag) {
1565       case JVM_CONSTANT_Utf8: {
1566         Symbol* sym = symbol_at(idx);
1567         symmap->add_entry(sym, idx);
1568         DBG(printf("adding symbol entry %s = %d\n", sym->as_utf8(), idx));
1569         break;
1570       }
1571       case JVM_CONSTANT_Class:
1572       case JVM_CONSTANT_UnresolvedClass:
1573       case JVM_CONSTANT_UnresolvedClassInError: {
1574         Symbol* sym = klass_name_at(idx);
1575         classmap->add_entry(sym, idx);
1576         DBG(printf("adding class entry %s = %d\n", sym->as_utf8(), idx));
1577         break;
1578       }
1579       case JVM_CONSTANT_Long:
1580       case JVM_CONSTANT_Double: {
1581         idx++; // Both Long and Double take two cpool slots
1582         break;
1583       }
1584     }
1585   }
1586   return size;
1587 } /* end hash_utf8_entries_to */
1588 
1589 
1590 // Copy cpool bytes.
1591 // Returns:
1592 //    0, in case of OutOfMemoryError
1593 //   -1, in case of internal error
1594 //  > 0, count of the raw cpool bytes that have been copied
1595 int ConstantPool::copy_cpool_bytes(int cpool_size,
1596                                           SymbolHashMap* tbl,
1597                                           unsigned char *bytes) {
1598   u2   idx1, idx2;
1599   jint size  = 0;
1600   jint cnt   = length();
1601   unsigned char *start_bytes = bytes;
1602 
1603   for (jint idx = 1; idx < cnt; idx++) {
1604     u1   tag      = tag_at(idx).value();
1605     jint ent_size = cpool_entry_size(idx);
1606 
1607     assert(size + ent_size <= cpool_size, "Size mismatch");
1608 
1609     *bytes = tag;
1610     DBG(printf("#%03hd tag=%03hd, ", idx, tag));
1611     switch(tag) {
1612       case JVM_CONSTANT_Invalid: {
1613         DBG(printf("JVM_CONSTANT_Invalid"));
1614         break;
1615       }
1616       case JVM_CONSTANT_Unicode: {
1617         assert(false, "Wrong constant pool tag: JVM_CONSTANT_Unicode");
1618         DBG(printf("JVM_CONSTANT_Unicode"));
1619         break;
1620       }
1621       case JVM_CONSTANT_Utf8: {
1622         Symbol* sym = symbol_at(idx);
1623         char*     str = sym->as_utf8();
1624         // Warning! It's crashing on x86 with len = sym->utf8_length()
1625         int       len = (int) strlen(str);
1626         Bytes::put_Java_u2((address) (bytes+1), (u2) len);
1627         for (int i = 0; i < len; i++) {
1628             bytes[3+i] = (u1) str[i];
1629         }
1630         DBG(printf("JVM_CONSTANT_Utf8: %s ", str));
1631         break;
1632       }
1633       case JVM_CONSTANT_Integer: {
1634         jint val = int_at(idx);
1635         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);
1636         break;
1637       }
1638       case JVM_CONSTANT_Float: {
1639         jfloat val = float_at(idx);
1640         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);
1641         break;
1642       }
1643       case JVM_CONSTANT_Long: {
1644         jlong val = long_at(idx);
1645         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);
1646         idx++;             // Long takes two cpool slots
1647         break;
1648       }
1649       case JVM_CONSTANT_Double: {
1650         jdouble val = double_at(idx);
1651         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);
1652         idx++;             // Double takes two cpool slots
1653         break;
1654       }
1655       case JVM_CONSTANT_Class:
1656       case JVM_CONSTANT_UnresolvedClass:
1657       case JVM_CONSTANT_UnresolvedClassInError: {
1658         *bytes = JVM_CONSTANT_Class;
1659         Symbol* sym = klass_name_at(idx);
1660         idx1 = tbl->symbol_to_value(sym);
1661         assert(idx1 != 0, "Have not found a hashtable entry");
1662         Bytes::put_Java_u2((address) (bytes+1), idx1);
1663         DBG(printf("JVM_CONSTANT_Class: idx=#%03hd, %s", idx1, sym->as_utf8()));
1664         break;
1665       }
1666       case JVM_CONSTANT_String: {
1667         *bytes = JVM_CONSTANT_String;
1668         Symbol* sym = unresolved_string_at(idx);
1669         idx1 = tbl->symbol_to_value(sym);
1670         assert(idx1 != 0, "Have not found a hashtable entry");
1671         Bytes::put_Java_u2((address) (bytes+1), idx1);
1672         DBG(char *str = sym->as_utf8());
1673         DBG(printf("JVM_CONSTANT_String: idx=#%03hd, %s", idx1, str));
1674         break;
1675       }
1676       case JVM_CONSTANT_Fieldref:
1677       case JVM_CONSTANT_Methodref:
1678       case JVM_CONSTANT_InterfaceMethodref: {
1679         idx1 = uncached_klass_ref_index_at(idx);
1680         idx2 = uncached_name_and_type_ref_index_at(idx);
1681         Bytes::put_Java_u2((address) (bytes+1), idx1);
1682         Bytes::put_Java_u2((address) (bytes+3), idx2);
1683         DBG(printf("JVM_CONSTANT_Methodref: %hd %hd", idx1, idx2));
1684         break;
1685       }
1686       case JVM_CONSTANT_NameAndType: {
1687         idx1 = name_ref_index_at(idx);
1688         idx2 = signature_ref_index_at(idx);
1689         Bytes::put_Java_u2((address) (bytes+1), idx1);
1690         Bytes::put_Java_u2((address) (bytes+3), idx2);
1691         DBG(printf("JVM_CONSTANT_NameAndType: %hd %hd", idx1, idx2));
1692         break;
1693       }
1694       case JVM_CONSTANT_ClassIndex: {
1695         *bytes = JVM_CONSTANT_Class;
1696         idx1 = klass_index_at(idx);
1697         Bytes::put_Java_u2((address) (bytes+1), idx1);
1698         DBG(printf("JVM_CONSTANT_ClassIndex: %hd", idx1));
1699         break;
1700       }
1701       case JVM_CONSTANT_StringIndex: {
1702         *bytes = JVM_CONSTANT_String;
1703         idx1 = string_index_at(idx);
1704         Bytes::put_Java_u2((address) (bytes+1), idx1);
1705         DBG(printf("JVM_CONSTANT_StringIndex: %hd", idx1));
1706         break;
1707       }
1708       case JVM_CONSTANT_MethodHandle:
1709       case JVM_CONSTANT_MethodHandleInError: {
1710         *bytes = JVM_CONSTANT_MethodHandle;
1711         int kind = method_handle_ref_kind_at(idx);
1712         idx1 = method_handle_index_at(idx);
1713         *(bytes+1) = (unsigned char) kind;
1714         Bytes::put_Java_u2((address) (bytes+2), idx1);
1715         DBG(printf("JVM_CONSTANT_MethodHandle: %d %hd", kind, idx1));
1716         break;
1717       }
1718       case JVM_CONSTANT_MethodType:
1719       case JVM_CONSTANT_MethodTypeInError: {
1720         *bytes = JVM_CONSTANT_MethodType;
1721         idx1 = method_type_index_at(idx);
1722         Bytes::put_Java_u2((address) (bytes+1), idx1);
1723         DBG(printf("JVM_CONSTANT_MethodType: %hd", idx1));
1724         break;
1725       }
1726       case JVM_CONSTANT_InvokeDynamic: {
1727         *bytes = tag;
1728         idx1 = extract_low_short_from_int(*int_at_addr(idx));
1729         idx2 = extract_high_short_from_int(*int_at_addr(idx));
1730         assert(idx2 == invoke_dynamic_name_and_type_ref_index_at(idx), "correct half of u4");
1731         Bytes::put_Java_u2((address) (bytes+1), idx1);
1732         Bytes::put_Java_u2((address) (bytes+3), idx2);
1733         DBG(printf("JVM_CONSTANT_InvokeDynamic: %hd %hd", idx1, idx2));
1734         break;
1735       }
1736     }
1737     DBG(printf("\n"));
1738     bytes += ent_size;
1739     size  += ent_size;
1740   }
1741   assert(size == cpool_size, "Size mismatch");
1742 
1743   // Keep temorarily for debugging until it's stable.
1744   DBG(print_cpool_bytes(cnt, start_bytes));
1745   return (int)(bytes - start_bytes);
1746 } /* end copy_cpool_bytes */
1747 
1748 
1749 void ConstantPool::set_on_stack(const bool value) {
1750   if (value) {
1751     _flags |= _on_stack;
1752   } else {
1753     _flags &= ~_on_stack;
1754   }
1755   if (value) MetadataOnStackMark::record(this);
1756 }
1757 
1758 // JSR 292 support for patching constant pool oops after the class is linked and
1759 // the oop array for resolved references are created.
1760 // We can't do this during classfile parsing, which is how the other indexes are
1761 // patched.  The other patches are applied early for some error checking
1762 // so only defer the pseudo_strings.
1763 void ConstantPool::patch_resolved_references(
1764                                             GrowableArray<Handle>* cp_patches) {
1765   assert(EnableInvokeDynamic, "");
1766   for (int index = 1; index < cp_patches->length(); index++) { // Index 0 is unused
1767     Handle patch = cp_patches->at(index);
1768     if (patch.not_null()) {
1769       assert (tag_at(index).is_string(), "should only be string left");
1770       // Patching a string means pre-resolving it.
1771       // The spelling in the constant pool is ignored.
1772       // The constant reference may be any object whatever.
1773       // If it is not a real interned string, the constant is referred
1774       // to as a "pseudo-string", and must be presented to the CP
1775       // explicitly, because it may require scavenging.
1776       int obj_index = cp_to_object_index(index);
1777       pseudo_string_at_put(index, obj_index, patch());
1778       DEBUG_ONLY(cp_patches->at_put(index, Handle());)
1779     }
1780   }
1781 #ifdef ASSERT
1782   // Ensure that all the patches have been used.
1783   for (int index = 0; index < cp_patches->length(); index++) {
1784     assert(cp_patches->at(index).is_null(),
1785            err_msg("Unused constant pool patch at %d in class file %s",
1786                    index,
1787                    pool_holder()->external_name()));
1788   }
1789 #endif // ASSERT
1790 }
1791 
1792 #ifndef PRODUCT
1793 
1794 // CompileTheWorld support. Preload all classes loaded references in the passed in constantpool
1795 void ConstantPool::preload_and_initialize_all_classes(ConstantPool* obj, TRAPS) {
1796   guarantee(obj->is_constantPool(), "object must be constant pool");
1797   constantPoolHandle cp(THREAD, (ConstantPool*)obj);
1798   guarantee(cp->pool_holder() != NULL, "must be fully loaded");
1799 
1800   for (int i = 0; i< cp->length();  i++) {
1801     if (cp->tag_at(i).is_unresolved_klass()) {
1802       // This will force loading of the class
1803       Klass* klass = cp->klass_at(i, CHECK);
1804       if (klass->oop_is_instance()) {
1805         // Force initialization of class
1806         InstanceKlass::cast(klass)->initialize(CHECK);
1807       }
1808     }
1809   }
1810 }
1811 
1812 #endif
1813 
1814 
1815 // Printing
1816 
1817 void ConstantPool::print_on(outputStream* st) const {
1818   EXCEPTION_MARK;
1819   assert(is_constantPool(), "must be constantPool");
1820   st->print_cr(internal_name());
1821   if (flags() != 0) {
1822     st->print(" - flags: 0x%x", flags());
1823     if (has_preresolution()) st->print(" has_preresolution");
1824     if (on_stack()) st->print(" on_stack");
1825     st->cr();
1826   }
1827   if (pool_holder() != NULL) {
1828     st->print_cr(" - holder: " INTPTR_FORMAT, pool_holder());
1829   }
1830   st->print_cr(" - cache: " INTPTR_FORMAT, cache());
1831   st->print_cr(" - resolved_references: " INTPTR_FORMAT, resolved_references());
1832   st->print_cr(" - reference_map: " INTPTR_FORMAT, reference_map());
1833 
1834   for (int index = 1; index < length(); index++) {      // Index 0 is unused
1835     ((ConstantPool*)this)->print_entry_on(index, st);
1836     switch (tag_at(index).value()) {
1837       case JVM_CONSTANT_Long :
1838       case JVM_CONSTANT_Double :
1839         index++;   // Skip entry following eigth-byte constant
1840     }
1841 
1842   }
1843   st->cr();
1844 }
1845 
1846 // Print one constant pool entry
1847 void ConstantPool::print_entry_on(const int index, outputStream* st) {
1848   EXCEPTION_MARK;
1849   st->print(" - %3d : ", index);
1850   tag_at(index).print_on(st);
1851   st->print(" : ");
1852   switch (tag_at(index).value()) {
1853     case JVM_CONSTANT_Class :
1854       { Klass* k = klass_at(index, CATCH);
1855         k->print_value_on(st);
1856         st->print(" {0x%lx}", (address)k);
1857       }
1858       break;
1859     case JVM_CONSTANT_Fieldref :
1860     case JVM_CONSTANT_Methodref :
1861     case JVM_CONSTANT_InterfaceMethodref :
1862       st->print("klass_index=%d", uncached_klass_ref_index_at(index));
1863       st->print(" name_and_type_index=%d", uncached_name_and_type_ref_index_at(index));
1864       break;
1865     case JVM_CONSTANT_String :
1866       if (is_pseudo_string_at(index)) {
1867         oop anObj = pseudo_string_at(index);
1868         anObj->print_value_on(st);
1869         st->print(" {0x%lx}", (address)anObj);
1870       } else {
1871         unresolved_string_at(index)->print_value_on(st);
1872       }
1873       break;
1874     case JVM_CONSTANT_Integer :
1875       st->print("%d", int_at(index));
1876       break;
1877     case JVM_CONSTANT_Float :
1878       st->print("%f", float_at(index));
1879       break;
1880     case JVM_CONSTANT_Long :
1881       st->print_jlong(long_at(index));
1882       break;
1883     case JVM_CONSTANT_Double :
1884       st->print("%lf", double_at(index));
1885       break;
1886     case JVM_CONSTANT_NameAndType :
1887       st->print("name_index=%d", name_ref_index_at(index));
1888       st->print(" signature_index=%d", signature_ref_index_at(index));
1889       break;
1890     case JVM_CONSTANT_Utf8 :
1891       symbol_at(index)->print_value_on(st);
1892       break;
1893     case JVM_CONSTANT_UnresolvedClass :               // fall-through
1894     case JVM_CONSTANT_UnresolvedClassInError: {
1895       // unresolved_klass_at requires lock or safe world.
1896       CPSlot entry = slot_at(index);
1897       if (entry.is_resolved()) {
1898         entry.get_klass()->print_value_on(st);
1899       } else {
1900         entry.get_symbol()->print_value_on(st);
1901       }
1902       }
1903       break;
1904     case JVM_CONSTANT_MethodHandle :
1905     case JVM_CONSTANT_MethodHandleInError :
1906       st->print("ref_kind=%d", method_handle_ref_kind_at(index));
1907       st->print(" ref_index=%d", method_handle_index_at(index));
1908       break;
1909     case JVM_CONSTANT_MethodType :
1910     case JVM_CONSTANT_MethodTypeInError :
1911       st->print("signature_index=%d", method_type_index_at(index));
1912       break;
1913     case JVM_CONSTANT_InvokeDynamic :
1914       {
1915         st->print("bootstrap_method_index=%d", invoke_dynamic_bootstrap_method_ref_index_at(index));
1916         st->print(" name_and_type_index=%d", invoke_dynamic_name_and_type_ref_index_at(index));
1917         int argc = invoke_dynamic_argument_count_at(index);
1918         if (argc > 0) {
1919           for (int arg_i = 0; arg_i < argc; arg_i++) {
1920             int arg = invoke_dynamic_argument_index_at(index, arg_i);
1921             st->print((arg_i == 0 ? " arguments={%d" : ", %d"), arg);
1922           }
1923           st->print("}");
1924         }
1925       }
1926       break;
1927     default:
1928       ShouldNotReachHere();
1929       break;
1930   }
1931   st->cr();
1932 }
1933 
1934 void ConstantPool::print_value_on(outputStream* st) const {
1935   assert(is_constantPool(), "must be constantPool");
1936   st->print("constant pool [%d]", length());
1937   if (has_preresolution()) st->print("/preresolution");
1938   if (operands() != NULL)  st->print("/operands[%d]", operands()->length());
1939   print_address_on(st);
1940   st->print(" for ");
1941   pool_holder()->print_value_on(st);
1942   if (pool_holder() != NULL) {
1943     bool extra = (pool_holder()->constants() != this);
1944     if (extra)  st->print(" (extra)");
1945   }
1946   if (cache() != NULL) {
1947     st->print(" cache=" PTR_FORMAT, cache());
1948   }
1949 }
1950 
1951 #if INCLUDE_SERVICES
1952 // Size Statistics
1953 void ConstantPool::collect_statistics(KlassSizeStats *sz) const {
1954   sz->_cp_all_bytes += (sz->_cp_bytes          = sz->count(this));
1955   sz->_cp_all_bytes += (sz->_cp_tags_bytes     = sz->count_array(tags()));
1956   sz->_cp_all_bytes += (sz->_cp_cache_bytes    = sz->count(cache()));
1957   sz->_cp_all_bytes += (sz->_cp_operands_bytes = sz->count_array(operands()));
1958   sz->_cp_all_bytes += (sz->_cp_refmap_bytes   = sz->count_array(reference_map()));
1959 
1960   sz->_ro_bytes += sz->_cp_operands_bytes + sz->_cp_tags_bytes +
1961                    sz->_cp_refmap_bytes;
1962   sz->_rw_bytes += sz->_cp_bytes + sz->_cp_cache_bytes;
1963 }
1964 #endif // INCLUDE_SERVICES
1965 
1966 // Verification
1967 
1968 void ConstantPool::verify_on(outputStream* st) {
1969   guarantee(is_constantPool(), "object must be constant pool");
1970   for (int i = 0; i< length();  i++) {
1971     constantTag tag = tag_at(i);
1972     CPSlot entry = slot_at(i);
1973     if (tag.is_klass()) {
1974       if (entry.is_resolved()) {
1975         guarantee(entry.get_klass()->is_metadata(), "should be metadata");
1976         guarantee(entry.get_klass()->is_klass(),    "should be klass");
1977       }
1978     } else if (tag.is_unresolved_klass()) {
1979       if (entry.is_resolved()) {
1980         guarantee(entry.get_klass()->is_metadata(), "should be metadata");
1981         guarantee(entry.get_klass()->is_klass(),    "should be klass");
1982       }
1983     } else if (tag.is_symbol()) {
1984       guarantee(entry.get_symbol()->refcount() != 0, "should have nonzero reference count");
1985     } else if (tag.is_string()) {
1986       guarantee(entry.get_symbol()->refcount() != 0, "should have nonzero reference count");
1987     }
1988   }
1989   if (cache() != NULL) {
1990     // Note: cache() can be NULL before a class is completely setup or
1991     // in temporary constant pools used during constant pool merging
1992     guarantee(cache()->is_metadata(),          "should be metadata");
1993     guarantee(cache()->is_constantPoolCache(), "should be constant pool cache");
1994   }
1995   if (pool_holder() != NULL) {
1996     // Note: pool_holder() can be NULL in temporary constant pools
1997     // used during constant pool merging
1998     guarantee(pool_holder()->is_metadata(), "should be metadata");
1999     guarantee(pool_holder()->is_klass(),    "should be klass");
2000   }
2001 }
2002 
2003 
2004 void SymbolHashMap::add_entry(Symbol* sym, u2 value) {
2005   char *str = sym->as_utf8();
2006   unsigned int hash = compute_hash(str, sym->utf8_length());
2007   unsigned int index = hash % table_size();
2008 
2009   // check if already in map
2010   // we prefer the first entry since it is more likely to be what was used in
2011   // the class file
2012   for (SymbolHashMapEntry *en = bucket(index); en != NULL; en = en->next()) {
2013     assert(en->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");
2014     if (en->hash() == hash && en->symbol() == sym) {
2015         return;  // already there
2016     }
2017   }
2018 
2019   SymbolHashMapEntry* entry = new SymbolHashMapEntry(hash, sym, value);
2020   entry->set_next(bucket(index));
2021   _buckets[index].set_entry(entry);
2022   assert(entry->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");
2023 }
2024 
2025 SymbolHashMapEntry* SymbolHashMap::find_entry(Symbol* sym) {
2026   assert(sym != NULL, "SymbolHashMap::find_entry - symbol is NULL");
2027   char *str = sym->as_utf8();
2028   int   len = sym->utf8_length();
2029   unsigned int hash = SymbolHashMap::compute_hash(str, len);
2030   unsigned int index = hash % table_size();
2031   for (SymbolHashMapEntry *en = bucket(index); en != NULL; en = en->next()) {
2032     assert(en->symbol() != NULL, "SymbolHashMapEntry symbol is NULL");
2033     if (en->hash() == hash && en->symbol() == sym) {
2034       return en;
2035     }
2036   }
2037   return NULL;
2038 }