1 /*
   2  * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "cds/archiveHeapWriter.hpp"
  27 #include "cds/archiveHeapLoader.hpp"
  28 #include "cds/archiveBuilder.hpp"
  29 #include "cds/classPrelinker.hpp"
  30 #include "cds/heapShared.hpp"
  31 #include "classfile/classLoaderData.hpp"
  32 #include "classfile/javaClasses.inline.hpp"
  33 #include "classfile/metadataOnStackMark.hpp"
  34 #include "classfile/stringTable.hpp"
  35 #include "classfile/systemDictionary.hpp"
  36 #include "classfile/vmClasses.hpp"
  37 #include "classfile/vmSymbols.hpp"
  38 #include "code/codeCache.hpp"
  39 #include "interpreter/bootstrapInfo.hpp"
  40 #include "interpreter/linkResolver.hpp"
  41 #include "jvm.h"
  42 #include "logging/log.hpp"
  43 #include "logging/logStream.hpp"
  44 #include "memory/allocation.inline.hpp"
  45 #include "memory/metadataFactory.hpp"
  46 #include "memory/metaspaceClosure.hpp"
  47 #include "memory/oopFactory.hpp"
  48 #include "memory/resourceArea.hpp"
  49 #include "memory/universe.hpp"
  50 #include "oops/array.hpp"
  51 #include "oops/constantPool.inline.hpp"
  52 #include "oops/cpCache.inline.hpp"
  53 #include "oops/flatArrayKlass.hpp"
  54 #include "oops/instanceKlass.hpp"
  55 #include "oops/klass.inline.hpp"
  56 #include "oops/objArrayKlass.hpp"
  57 #include "oops/objArrayOop.inline.hpp"
  58 #include "oops/oop.inline.hpp"
  59 #include "oops/typeArrayOop.inline.hpp"
  60 #include "prims/jvmtiExport.hpp"
  61 #include "runtime/atomic.hpp"
  62 #include "runtime/handles.inline.hpp"
  63 #include "runtime/init.hpp"
  64 #include "runtime/javaCalls.hpp"
  65 #include "runtime/javaThread.hpp"
  66 #include "runtime/signature.hpp"
  67 #include "runtime/vframe.inline.hpp"
  68 #include "utilities/copy.hpp"
  69 
  70 ConstantPool* ConstantPool::allocate(ClassLoaderData* loader_data, int length, TRAPS) {
  71   Array<u1>* tags = MetadataFactory::new_array<u1>(loader_data, length, 0, CHECK_NULL);
  72   int size = ConstantPool::size(length);
  73   return new (loader_data, size, MetaspaceObj::ConstantPoolType, THREAD) ConstantPool(tags);
  74 }
  75 
  76 void ConstantPool::copy_fields(const ConstantPool* orig) {
  77   // Preserve dynamic constant information from the original pool
  78   if (orig->has_dynamic_constant()) {
  79     set_has_dynamic_constant();
  80   }
  81 
  82   set_major_version(orig->major_version());
  83   set_minor_version(orig->minor_version());
  84 
  85   set_source_file_name_index(orig->source_file_name_index());
  86   set_generic_signature_index(orig->generic_signature_index());
  87 }
  88 
  89 #ifdef ASSERT
  90 
  91 // MetaspaceObj allocation invariant is calloc equivalent memory
  92 // simple verification of this here (JVM_CONSTANT_Invalid == 0 )
  93 static bool tag_array_is_zero_initialized(Array<u1>* tags) {
  94   assert(tags != nullptr, "invariant");
  95   const int length = tags->length();
  96   for (int index = 0; index < length; ++index) {
  97     if (JVM_CONSTANT_Invalid != tags->at(index)) {
  98       return false;
  99     }
 100   }
 101   return true;
 102 }
 103 
 104 #endif
 105 
 106 ConstantPool::ConstantPool(Array<u1>* tags) :
 107   _tags(tags),
 108   _length(tags->length()) {
 109 
 110     assert(_tags != nullptr, "invariant");
 111     assert(tags->length() == _length, "invariant");
 112     assert(tag_array_is_zero_initialized(tags), "invariant");
 113     assert(0 == flags(), "invariant");
 114     assert(0 == version(), "invariant");
 115     assert(nullptr == _pool_holder, "invariant");
 116 }
 117 
 118 void ConstantPool::deallocate_contents(ClassLoaderData* loader_data) {
 119   if (cache() != nullptr) {
 120     MetadataFactory::free_metadata(loader_data, cache());
 121     set_cache(nullptr);
 122   }
 123 
 124   MetadataFactory::free_array<Klass*>(loader_data, resolved_klasses());
 125   set_resolved_klasses(nullptr);
 126 
 127   MetadataFactory::free_array<jushort>(loader_data, operands());
 128   set_operands(nullptr);
 129 
 130   release_C_heap_structures();
 131 
 132   // free tag array
 133   MetadataFactory::free_array<u1>(loader_data, tags());
 134   set_tags(nullptr);
 135 }
 136 
 137 void ConstantPool::release_C_heap_structures() {
 138   // walk constant pool and decrement symbol reference counts
 139   unreference_symbols();
 140 }
 141 
 142 void ConstantPool::metaspace_pointers_do(MetaspaceClosure* it) {
 143   log_trace(cds)("Iter(ConstantPool): %p", this);
 144 
 145   it->push(&_tags, MetaspaceClosure::_writable);
 146   it->push(&_cache);
 147   it->push(&_pool_holder);
 148   it->push(&_operands);
 149   it->push(&_resolved_klasses, MetaspaceClosure::_writable);
 150 
 151   for (int i = 0; i < length(); i++) {
 152     // The only MSO's embedded in the CP entries are Symbols:
 153     //   JVM_CONSTANT_String (normal and pseudo)
 154     //   JVM_CONSTANT_Utf8
 155     constantTag ctag = tag_at(i);
 156     if (ctag.is_string() || ctag.is_utf8()) {
 157       it->push(symbol_at_addr(i));
 158     }
 159   }
 160 }
 161 
 162 objArrayOop ConstantPool::resolved_references() const {
 163   return _cache->resolved_references();
 164 }
 165 
 166 // Called from outside constant pool resolution where a resolved_reference array
 167 // may not be present.
 168 objArrayOop ConstantPool::resolved_references_or_null() const {
 169   if (_cache == nullptr) {
 170     return nullptr;
 171   } else {
 172     return _cache->resolved_references();
 173   }
 174 }
 175 
 176 oop ConstantPool::resolved_reference_at(int index) const {
 177   oop result = resolved_references()->obj_at(index);
 178   assert(oopDesc::is_oop_or_null(result), "Must be oop");
 179   return result;
 180 }
 181 
 182 // Use a CAS for multithreaded access
 183 oop ConstantPool::set_resolved_reference_at(int index, oop new_result) {
 184   assert(oopDesc::is_oop_or_null(new_result), "Must be oop");
 185   return resolved_references()->replace_if_null(index, new_result);
 186 }
 187 
 188 // Create resolved_references array and mapping array for original cp indexes
 189 // The ldc bytecode was rewritten to have the resolved reference array index so need a way
 190 // to map it back for resolving and some unlikely miscellaneous uses.
 191 // The objects created by invokedynamic are appended to this list.
 192 void ConstantPool::initialize_resolved_references(ClassLoaderData* loader_data,
 193                                                   const intStack& reference_map,
 194                                                   int constant_pool_map_length,
 195                                                   TRAPS) {
 196   // Initialized the resolved object cache.
 197   int map_length = reference_map.length();
 198   if (map_length > 0) {
 199     // Only need mapping back to constant pool entries.  The map isn't used for
 200     // invokedynamic resolved_reference entries.  For invokedynamic entries,
 201     // the constant pool cache index has the mapping back to both the constant
 202     // pool and to the resolved reference index.
 203     if (constant_pool_map_length > 0) {
 204       Array<u2>* om = MetadataFactory::new_array<u2>(loader_data, constant_pool_map_length, CHECK);
 205 
 206       for (int i = 0; i < constant_pool_map_length; i++) {
 207         int x = reference_map.at(i);
 208         assert(x == (int)(jushort) x, "klass index is too big");
 209         om->at_put(i, (jushort)x);
 210       }
 211       set_reference_map(om);
 212     }
 213 
 214     // Create Java array for holding resolved strings, methodHandles,
 215     // methodTypes, invokedynamic and invokehandle appendix objects, etc.
 216     objArrayOop stom = oopFactory::new_objArray(vmClasses::Object_klass(), map_length, CHECK);
 217     HandleMark hm(THREAD);
 218     Handle refs_handle (THREAD, stom);  // must handleize.
 219     set_resolved_references(loader_data->add_handle(refs_handle));
 220   }
 221 }
 222 
 223 void ConstantPool::allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS) {
 224   // A ConstantPool can't possibly have 0xffff valid class entries,
 225   // because entry #0 must be CONSTANT_Invalid, and each class entry must refer to a UTF8
 226   // entry for the class's name. So at most we will have 0xfffe class entries.
 227   // This allows us to use 0xffff (ConstantPool::_temp_resolved_klass_index) to indicate
 228   // UnresolvedKlass entries that are temporarily created during class redefinition.
 229   assert(num_klasses < CPKlassSlot::_temp_resolved_klass_index, "sanity");
 230   assert(resolved_klasses() == nullptr, "sanity");
 231   Array<Klass*>* rk = MetadataFactory::new_array<Klass*>(loader_data, num_klasses, CHECK);
 232   set_resolved_klasses(rk);
 233 }
 234 
 235 void ConstantPool::initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS) {
 236   int len = length();
 237   int num_klasses = 0;
 238   for (int i = 1; i <len; i++) {
 239     switch (tag_at(i).value()) {
 240     case JVM_CONSTANT_ClassIndex:
 241       {
 242         const int class_index = klass_index_at(i);
 243         unresolved_klass_at_put(i, class_index, num_klasses++);
 244       }
 245       break;
 246 #ifndef PRODUCT
 247     case JVM_CONSTANT_Class:
 248     case JVM_CONSTANT_UnresolvedClass:
 249     case JVM_CONSTANT_UnresolvedClassInError:
 250       // All of these should have been reverted back to Unresolved before calling
 251       // this function.
 252       ShouldNotReachHere();
 253 #endif
 254     }
 255   }
 256   allocate_resolved_klasses(loader_data, num_klasses, THREAD);
 257 }
 258 
 259 // Hidden class support:
 260 void ConstantPool::klass_at_put(int class_index, Klass* k) {
 261   assert(k != nullptr, "must be valid klass");
 262   CPKlassSlot kslot = klass_slot_at(class_index);
 263   int resolved_klass_index = kslot.resolved_klass_index();
 264   Klass** adr = resolved_klasses()->adr_at(resolved_klass_index);
 265   Atomic::release_store(adr, k);
 266 
 267   // The interpreter assumes when the tag is stored, the klass is resolved
 268   // and the Klass* non-null, so we need hardware store ordering here.
 269   assert(!k->name()->is_Q_signature(), "Q-type without JVM_CONSTANT_QDescBit");
 270   release_tag_at_put(class_index, JVM_CONSTANT_Class);
 271 }
 272 
 273 #if INCLUDE_CDS_JAVA_HEAP
 274 // Returns the _resolved_reference array after removing unarchivable items from it.
 275 // Returns null if this class is not supported, or _resolved_reference doesn't exist.
 276 objArrayOop ConstantPool::prepare_resolved_references_for_archiving() {
 277   if (_cache == nullptr) {
 278     return nullptr; // nothing to do
 279   }
 280 
 281   InstanceKlass *ik = pool_holder();
 282   if (!(ik->is_shared_boot_class() || ik->is_shared_platform_class() ||
 283         ik->is_shared_app_class())) {
 284     // Archiving resolved references for classes from non-builtin loaders
 285     // is not yet supported.
 286     return nullptr;
 287   }
 288 
 289   objArrayOop rr = resolved_references();
 290   if (rr != nullptr) {
 291     Array<u2>* ref_map = reference_map();
 292     int ref_map_len = ref_map == nullptr ? 0 : ref_map->length();
 293     int rr_len = rr->length();
 294     for (int i = 0; i < rr_len; i++) {
 295       oop obj = rr->obj_at(i);
 296       rr->obj_at_put(i, nullptr);
 297       if (obj != nullptr && i < ref_map_len) {
 298         int index = object_to_cp_index(i);
 299         if (tag_at(index).is_string()) {
 300           assert(java_lang_String::is_instance(obj), "must be");
 301           if (!ArchiveHeapWriter::is_string_too_large_to_archive(obj)) {
 302             rr->obj_at_put(i, obj);
 303           }
 304         }
 305       }
 306     }
 307   }
 308   return rr;
 309 }
 310 
 311 void ConstantPool::add_dumped_interned_strings() {
 312   objArrayOop rr = resolved_references();
 313   if (rr != nullptr) {
 314     int rr_len = rr->length();
 315     for (int i = 0; i < rr_len; i++) {
 316       oop p = rr->obj_at(i);
 317       if (java_lang_String::is_instance(p) &&
 318           !ArchiveHeapWriter::is_string_too_large_to_archive(p)) {
 319         HeapShared::add_to_dumped_interned_strings(p);
 320       }
 321     }
 322   }
 323 }
 324 #endif
 325 
 326 #if INCLUDE_CDS
 327 // CDS support. Create a new resolved_references array.
 328 void ConstantPool::restore_unshareable_info(TRAPS) {
 329   if (!_pool_holder->is_linked() && !_pool_holder->is_rewritten()) {
 330     return;
 331   }
 332   assert(is_constantPool(), "ensure C++ vtable is restored");
 333   assert(on_stack(), "should always be set for shared constant pools");
 334   assert(is_shared(), "should always be set for shared constant pools");
 335   assert(_cache != nullptr, "constant pool _cache should not be null");
 336 
 337   // Only create the new resolved references array if it hasn't been attempted before
 338   if (resolved_references() != nullptr) return;
 339 
 340   if (vmClasses::Object_klass_loaded()) {
 341     ClassLoaderData* loader_data = pool_holder()->class_loader_data();
 342 #if INCLUDE_CDS_JAVA_HEAP
 343     if (ArchiveHeapLoader::is_in_use() &&
 344         _cache->archived_references() != nullptr) {
 345       oop archived = _cache->archived_references();
 346       // Create handle for the archived resolved reference array object
 347       HandleMark hm(THREAD);
 348       Handle refs_handle(THREAD, archived);
 349       set_resolved_references(loader_data->add_handle(refs_handle));
 350       _cache->clear_archived_references();
 351     } else
 352 #endif
 353     {
 354       // No mapped archived resolved reference array
 355       // Recreate the object array and add to ClassLoaderData.
 356       int map_length = resolved_reference_length();
 357       if (map_length > 0) {
 358         objArrayOop stom = oopFactory::new_objArray(vmClasses::Object_klass(), map_length, CHECK);
 359         HandleMark hm(THREAD);
 360         Handle refs_handle(THREAD, stom);  // must handleize.
 361         set_resolved_references(loader_data->add_handle(refs_handle));
 362       }
 363     }
 364   }
 365 }
 366 
 367 void ConstantPool::remove_unshareable_info() {
 368   // Shared ConstantPools are in the RO region, so the _flags cannot be modified.
 369   // The _on_stack flag is used to prevent ConstantPools from deallocation during
 370   // class redefinition. Since shared ConstantPools cannot be deallocated anyway,
 371   // we always set _on_stack to true to avoid having to change _flags during runtime.
 372   _flags |= (_on_stack | _is_shared);
 373 
 374   if (!_pool_holder->is_linked() && !_pool_holder->verified_at_dump_time()) {
 375     return;
 376   }
 377   // Resolved references are not in the shared archive.
 378   // Save the length for restoration.  It is not necessarily the same length
 379   // as reference_map.length() if invokedynamic is saved. It is needed when
 380   // re-creating the resolved reference array if archived heap data cannot be map
 381   // at runtime.
 382   set_resolved_reference_length(
 383     resolved_references() != nullptr ? resolved_references()->length() : 0);
 384   set_resolved_references(OopHandle());
 385 
 386   bool archived = false;
 387   for (int index = 1; index < length(); index++) { // Index 0 is unused
 388     switch (tag_at(index).value()) {
 389     case JVM_CONSTANT_UnresolvedClassInError:
 390       {
 391         jbyte qdesc_bit = tag_at(index).is_Qdescriptor_klass() ? (jbyte) JVM_CONSTANT_QDescBit : 0;
 392         tag_at_put(index, JVM_CONSTANT_UnresolvedClass | qdesc_bit);
 393       }
 394       break;
 395     case JVM_CONSTANT_MethodHandleInError:
 396       tag_at_put(index, JVM_CONSTANT_MethodHandle);
 397       break;
 398     case JVM_CONSTANT_MethodTypeInError:
 399       tag_at_put(index, JVM_CONSTANT_MethodType);
 400       break;
 401     case JVM_CONSTANT_DynamicInError:
 402       tag_at_put(index, JVM_CONSTANT_Dynamic);
 403       break;
 404     case JVM_CONSTANT_Class:
 405       archived = maybe_archive_resolved_klass_at(index);
 406       ArchiveBuilder::alloc_stats()->record_klass_cp_entry(archived);
 407       break;
 408     }
 409   }
 410 
 411   if (cache() != nullptr) {
 412     // cache() is null if this class is not yet linked.
 413     cache()->remove_unshareable_info();
 414   }
 415 }
 416 
 417 bool ConstantPool::maybe_archive_resolved_klass_at(int cp_index) {
 418   assert(ArchiveBuilder::current()->is_in_buffer_space(this), "must be");
 419   assert(tag_at(cp_index).is_klass(), "must be resolved");
 420 
 421   if (pool_holder()->is_hidden() && cp_index == pool_holder()->this_class_index()) {
 422     // All references to a hidden class's own field/methods are through this
 423     // index, which was resolved in ClassFileParser::fill_instance_klass. We
 424     // must preserve it.
 425     return true;
 426   }
 427 
 428   CPKlassSlot kslot = klass_slot_at(cp_index);
 429   int resolved_klass_index = kslot.resolved_klass_index();
 430   Klass* k = resolved_klasses()->at(resolved_klass_index);
 431   // k could be null if the referenced class has been excluded via
 432   // SystemDictionaryShared::is_excluded_class().
 433 
 434   if (k != nullptr) {
 435     ConstantPool* src_cp = ArchiveBuilder::current()->get_source_addr(this);
 436     if (ClassPrelinker::can_archive_resolved_klass(src_cp, cp_index)) {
 437       if (log_is_enabled(Debug, cds, resolve)) {
 438         ResourceMark rm;
 439         log_debug(cds, resolve)("Resolved klass CP entry [%d]: %s => %s", cp_index,
 440                                 pool_holder()->external_name(), k->external_name());
 441       }
 442       return true;
 443     }
 444   }
 445 
 446   // This referenced class cannot be archived. Revert the tag to UnresolvedClass,
 447   // so that the proper class loading and initialization can happen at runtime.
 448   resolved_klasses()->at_put(resolved_klass_index, nullptr);
 449   jbyte qdesc_bit = tag_at(cp_index).is_Qdescriptor_klass() ? (jbyte) JVM_CONSTANT_QDescBit : 0;
 450   tag_at_put(cp_index, JVM_CONSTANT_UnresolvedClass | qdesc_bit);
 451   return false;
 452 }
 453 #endif // INCLUDE_CDS
 454 
 455 int ConstantPool::cp_to_object_index(int cp_index) {
 456   // this is harder don't do this so much.
 457   int i = reference_map()->find(cp_index);
 458   // We might not find the index for jsr292 call.
 459   return (i < 0) ? _no_index_sentinel : i;
 460 }
 461 
 462 void ConstantPool::string_at_put(int which, int obj_index, oop str) {
 463   oop result = set_resolved_reference_at(obj_index, str);
 464   assert(result == nullptr || result == str, "Only set once or to the same string.");
 465 }
 466 
 467 void ConstantPool::trace_class_resolution(const constantPoolHandle& this_cp, Klass* k) {
 468   ResourceMark rm;
 469   int line_number = -1;
 470   const char * source_file = nullptr;
 471   if (JavaThread::current()->has_last_Java_frame()) {
 472     // try to identify the method which called this function.
 473     vframeStream vfst(JavaThread::current());
 474     if (!vfst.at_end()) {
 475       line_number = vfst.method()->line_number_from_bci(vfst.bci());
 476       Symbol* s = vfst.method()->method_holder()->source_file_name();
 477       if (s != nullptr) {
 478         source_file = s->as_C_string();
 479       }
 480     }
 481   }
 482   if (k != this_cp->pool_holder()) {
 483     // only print something if the classes are different
 484     if (source_file != nullptr) {
 485       log_debug(class, resolve)("%s %s %s:%d",
 486                  this_cp->pool_holder()->external_name(),
 487                  k->external_name(), source_file, line_number);
 488     } else {
 489       log_debug(class, resolve)("%s %s",
 490                  this_cp->pool_holder()->external_name(),
 491                  k->external_name());
 492     }
 493   }
 494 }
 495 
 496 void check_is_inline_type(Klass* k, TRAPS) {
 497   if (!k->is_inline_klass()) {
 498     THROW(vmSymbols::java_lang_IncompatibleClassChangeError());
 499   }
 500 }
 501 
 502 Klass* ConstantPool::klass_at_impl(const constantPoolHandle& this_cp, int which,
 503                                    TRAPS) {
 504   JavaThread* javaThread = THREAD;
 505 
 506   // A resolved constantPool entry will contain a Klass*, otherwise a Symbol*.
 507   // It is not safe to rely on the tag bit's here, since we don't have a lock, and
 508   // the entry and tag is not updated atomically.
 509   CPKlassSlot kslot = this_cp->klass_slot_at(which);
 510   int resolved_klass_index = kslot.resolved_klass_index();
 511   int name_index = kslot.name_index();
 512   assert(this_cp->tag_at(name_index).is_symbol(), "sanity");
 513 
 514   // The tag must be JVM_CONSTANT_Class in order to read the correct value from
 515   // the unresolved_klasses() array.
 516   if (this_cp->tag_at(which).is_klass()) {
 517     Klass* klass = this_cp->resolved_klasses()->at(resolved_klass_index);
 518     if (klass != nullptr) {
 519       return klass;
 520     }
 521   }
 522 
 523   // This tag doesn't change back to unresolved class unless at a safepoint.
 524   if (this_cp->tag_at(which).is_unresolved_klass_in_error()) {
 525     // The original attempt to resolve this constant pool entry failed so find the
 526     // class of the original error and throw another error of the same class
 527     // (JVMS 5.4.3).
 528     // If there is a detail message, pass that detail message to the error.
 529     // The JVMS does not strictly require us to duplicate the same detail message,
 530     // or any internal exception fields such as cause or stacktrace.  But since the
 531     // detail message is often a class name or other literal string, we will repeat it
 532     // if we can find it in the symbol table.
 533     throw_resolution_error(this_cp, which, CHECK_NULL);
 534     ShouldNotReachHere();
 535   }
 536 
 537   HandleMark hm(THREAD);
 538   Handle mirror_handle;
 539   Symbol* name = this_cp->symbol_at(name_index);
 540   bool inline_type_signature = false;
 541   if (name->is_Q_signature()) {
 542     name = name->fundamental_name(THREAD);
 543     inline_type_signature = true;
 544   }
 545   Handle loader (THREAD, this_cp->pool_holder()->class_loader());
 546   Handle protection_domain (THREAD, this_cp->pool_holder()->protection_domain());
 547 
 548   Klass* k;
 549   {
 550     // Turn off the single stepping while doing class resolution
 551     JvmtiHideSingleStepping jhss(javaThread);
 552     k = SystemDictionary::resolve_or_fail(name, loader, protection_domain, true, THREAD);
 553   } //  JvmtiHideSingleStepping jhss(javaThread);
 554   if (inline_type_signature) {
 555     name->decrement_refcount();
 556   }
 557 
 558   if (!HAS_PENDING_EXCEPTION) {
 559     // preserve the resolved klass from unloading
 560     mirror_handle = Handle(THREAD, k->java_mirror());
 561     // Do access check for klasses
 562     verify_constant_pool_resolve(this_cp, k, THREAD);
 563   }
 564 
 565   if (!HAS_PENDING_EXCEPTION && inline_type_signature) {
 566     check_is_inline_type(k, THREAD);
 567   }
 568 
 569   if (!HAS_PENDING_EXCEPTION) {
 570     Klass* bottom_klass = nullptr;
 571     if (k->is_objArray_klass()) {
 572       bottom_klass = ObjArrayKlass::cast(k)->bottom_klass();
 573       assert(bottom_klass != nullptr, "Should be set");
 574       assert(bottom_klass->is_instance_klass() || bottom_klass->is_typeArray_klass(), "Sanity check");
 575     } else if (k->is_flatArray_klass()) {
 576       bottom_klass = FlatArrayKlass::cast(k)->element_klass();
 577       assert(bottom_klass != nullptr, "Should be set");
 578     }
 579   }
 580 
 581   // Failed to resolve class. We must record the errors so that subsequent attempts
 582   // to resolve this constant pool entry fail with the same error (JVMS 5.4.3).
 583   if (HAS_PENDING_EXCEPTION) {
 584     jbyte tag = JVM_CONSTANT_UnresolvedClass;
 585     if (this_cp->tag_at(which).is_Qdescriptor_klass()) {
 586       tag |= JVM_CONSTANT_QDescBit;
 587     }
 588     save_and_throw_exception(this_cp, which, constantTag(tag), CHECK_NULL);
 589     // If CHECK_NULL above doesn't return the exception, that means that
 590     // some other thread has beaten us and has resolved the class.
 591     // To preserve old behavior, we return the resolved class.
 592     Klass* klass = this_cp->resolved_klasses()->at(resolved_klass_index);
 593     assert(klass != nullptr, "must be resolved if exception was cleared");
 594     return klass;
 595   }
 596 
 597   // logging for class+resolve.
 598   if (log_is_enabled(Debug, class, resolve)){
 599     trace_class_resolution(this_cp, k);
 600   }
 601 
 602   Klass** adr = this_cp->resolved_klasses()->adr_at(resolved_klass_index);
 603   Atomic::release_store(adr, k);
 604   // The interpreter assumes when the tag is stored, the klass is resolved
 605   // and the Klass* stored in _resolved_klasses is non-null, so we need
 606   // hardware store ordering here.
 607   jbyte tag = JVM_CONSTANT_Class;
 608   if (this_cp->tag_at(which).is_Qdescriptor_klass()) {
 609     tag |= JVM_CONSTANT_QDescBit;
 610   }
 611   // We also need to CAS to not overwrite an error from a racing thread.
 612 
 613   jbyte old_tag = Atomic::cmpxchg((jbyte*)this_cp->tag_addr_at(which),
 614                                   (jbyte)JVM_CONSTANT_UnresolvedClass,
 615                                   tag);
 616 
 617   // We need to recheck exceptions from racing thread and return the same.
 618   if (old_tag == JVM_CONSTANT_UnresolvedClassInError) {
 619     // Remove klass.
 620     this_cp->resolved_klasses()->at_put(resolved_klass_index, nullptr);
 621     throw_resolution_error(this_cp, which, CHECK_NULL);
 622   }
 623 
 624   return k;
 625 }
 626 
 627 
 628 // Does not update ConstantPool* - to avoid any exception throwing. Used
 629 // by compiler and exception handling.  Also used to avoid classloads for
 630 // instanceof operations. Returns null if the class has not been loaded or
 631 // if the verification of constant pool failed
 632 Klass* ConstantPool::klass_at_if_loaded(const constantPoolHandle& this_cp, int which) {
 633   CPKlassSlot kslot = this_cp->klass_slot_at(which);
 634   int resolved_klass_index = kslot.resolved_klass_index();
 635   int name_index = kslot.name_index();
 636   assert(this_cp->tag_at(name_index).is_symbol(), "sanity");
 637 
 638   if (this_cp->tag_at(which).is_klass()) {
 639     Klass* k = this_cp->resolved_klasses()->at(resolved_klass_index);
 640     assert(k != nullptr, "should be resolved");
 641     return k;
 642   } else if (this_cp->tag_at(which).is_unresolved_klass_in_error()) {
 643     return nullptr;
 644   } else {
 645     Thread* current = Thread::current();
 646     HandleMark hm(current);
 647     Symbol* name = this_cp->symbol_at(name_index);
 648     oop loader = this_cp->pool_holder()->class_loader();
 649     oop protection_domain = this_cp->pool_holder()->protection_domain();
 650     Handle h_prot (current, protection_domain);
 651     Handle h_loader (current, loader);
 652     Klass* k = SystemDictionary::find_instance_klass(current, name, h_loader, h_prot);
 653 
 654     // Avoid constant pool verification at a safepoint, as it takes the Module_lock.
 655     if (k != nullptr && current->is_Java_thread()) {
 656       // Make sure that resolving is legal
 657       JavaThread* THREAD = JavaThread::cast(current); // For exception macros.
 658       ExceptionMark em(THREAD);
 659       // return null if verification fails
 660       verify_constant_pool_resolve(this_cp, k, THREAD);
 661       if (HAS_PENDING_EXCEPTION) {
 662         CLEAR_PENDING_EXCEPTION;
 663         return nullptr;
 664       }
 665       return k;
 666     } else {
 667       return k;
 668     }
 669   }
 670 }
 671 
 672 Method* ConstantPool::method_at_if_loaded(const constantPoolHandle& cpool,
 673                                                    int which) {
 674   if (cpool->cache() == nullptr)  return nullptr;  // nothing to load yet
 675   int cache_index = decode_cpcache_index(which, true);
 676   if (!(cache_index >= 0 && cache_index < cpool->cache()->length())) {
 677     // FIXME: should be an assert
 678     log_debug(class, resolve)("bad operand %d in:", which); cpool->print();
 679     return nullptr;
 680   }
 681   ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 682   return e->method_if_resolved(cpool);
 683 }
 684 
 685 
 686 bool ConstantPool::has_appendix_at_if_loaded(const constantPoolHandle& cpool, int which) {
 687   if (cpool->cache() == nullptr)  return false;  // nothing to load yet
 688   if (is_invokedynamic_index(which)) {
 689     int indy_index = decode_invokedynamic_index(which);
 690     return cpool->resolved_indy_entry_at(indy_index)->has_appendix();
 691   } else {
 692     int cache_index = decode_cpcache_index(which, true);
 693     ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 694     return e->has_appendix();
 695   }
 696 }
 697 
 698 oop ConstantPool::appendix_at_if_loaded(const constantPoolHandle& cpool, int which) {
 699   if (cpool->cache() == nullptr)  return nullptr;  // nothing to load yet
 700   if (is_invokedynamic_index(which)) {
 701     int indy_index = decode_invokedynamic_index(which);
 702     return cpool->resolved_reference_from_indy(indy_index);
 703   } else {
 704     int cache_index = decode_cpcache_index(which, true);
 705     ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 706     return e->appendix_if_resolved(cpool);
 707   }
 708 }
 709 
 710 
 711 bool ConstantPool::has_local_signature_at_if_loaded(const constantPoolHandle& cpool, int which) {
 712   if (cpool->cache() == nullptr)  return false;  // nothing to load yet
 713   int cache_index = decode_cpcache_index(which, true);
 714   if (is_invokedynamic_index(which)) {
 715     return cpool->resolved_indy_entry_at(cache_index)->has_local_signature();
 716   } else {
 717     ConstantPoolCacheEntry* e = cpool->cache()->entry_at(cache_index);
 718     return e->has_local_signature();
 719   }
 720 }
 721 
 722 // Translate index, which could be CPCache index or Indy index, to a constant pool index
 723 int ConstantPool::to_cp_index(int index, Bytecodes::Code code) {
 724   assert(cache() != nullptr, "'index' is a rewritten index so this class must have been rewritten");
 725   switch(code) {
 726     case Bytecodes::_invokedynamic:
 727       return invokedynamic_bootstrap_ref_index_at(index);
 728     case Bytecodes::_getfield:
 729     case Bytecodes::_getstatic:
 730     case Bytecodes::_putfield:
 731     case Bytecodes::_putstatic:
 732       // TODO: handle resolved field entries with new structure
 733       // i = ....
 734     case Bytecodes::_invokeinterface:
 735     case Bytecodes::_invokehandle:
 736     case Bytecodes::_invokespecial:
 737     case Bytecodes::_invokestatic:
 738     case Bytecodes::_invokevirtual:
 739       // TODO: handle resolved method entries with new structure
 740     default:
 741       // change byte-ordering and go via cache
 742       return remap_instruction_operand_from_cache(index);
 743   }
 744 }
 745 
 746 int ConstantPool::uncached_name_and_type_ref_index_at(int cp_index)  {
 747   if (tag_at(cp_index).has_bootstrap()) {
 748     int pool_index = bootstrap_name_and_type_ref_index_at(cp_index);
 749     assert(tag_at(pool_index).is_name_and_type(), "");
 750     return pool_index;
 751   }
 752   assert(tag_at(cp_index).is_field_or_method(), "Corrupted constant pool");
 753   assert(!tag_at(cp_index).has_bootstrap(), "Must be handled above");
 754   jint ref_index = *int_at_addr(cp_index);
 755   return extract_high_short_from_int(ref_index);
 756 }
 757 
 758 int ConstantPool::name_and_type_ref_index_at(int index, Bytecodes::Code code) {
 759   return uncached_name_and_type_ref_index_at(to_cp_index(index, code));
 760 }
 761 
 762 constantTag ConstantPool::tag_ref_at(int which, Bytecodes::Code code) {
 763   // which may be either a Constant Pool index or a rewritten index
 764   int pool_index = which;
 765   assert(cache() != nullptr, "'index' is a rewritten index so this class must have been rewritten");
 766   pool_index = to_cp_index(which, code);
 767   return tag_at(pool_index);
 768 }
 769 
 770 int ConstantPool::uncached_klass_ref_index_at(int cp_index) {
 771   assert(tag_at(cp_index).is_field_or_method(), "Corrupted constant pool");
 772   jint ref_index = *int_at_addr(cp_index);
 773   return extract_low_short_from_int(ref_index);
 774 }
 775 
 776 int ConstantPool::klass_ref_index_at(int index, Bytecodes::Code code) {
 777   guarantee(!ConstantPool::is_invokedynamic_index(index),
 778             "an invokedynamic instruction does not have a klass");
 779   assert(code != Bytecodes::_invokedynamic,
 780             "an invokedynamic instruction does not have a klass");
 781   return uncached_klass_ref_index_at(to_cp_index(index, code));
 782 }
 783 
 784 
 785 int ConstantPool::remap_instruction_operand_from_cache(int operand) {
 786   int cpc_index = operand;
 787   DEBUG_ONLY(cpc_index -= CPCACHE_INDEX_TAG);
 788   assert((int)(u2)cpc_index == cpc_index, "clean u2");
 789   int member_index = cache()->entry_at(cpc_index)->constant_pool_index();
 790   return member_index;
 791 }
 792 
 793 
 794 void ConstantPool::verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* k, TRAPS) {
 795   if (!(k->is_instance_klass() || k->is_objArray_klass())) {
 796     return;  // short cut, typeArray klass is always accessible
 797   }
 798   Klass* holder = this_cp->pool_holder();
 799   LinkResolver::check_klass_accessibility(holder, k, CHECK);
 800 }
 801 
 802 
 803 int ConstantPool::name_ref_index_at(int which_nt) {
 804   jint ref_index = name_and_type_at(which_nt);
 805   return extract_low_short_from_int(ref_index);
 806 }
 807 
 808 
 809 int ConstantPool::signature_ref_index_at(int which_nt) {
 810   jint ref_index = name_and_type_at(which_nt);
 811   return extract_high_short_from_int(ref_index);
 812 }
 813 
 814 
 815 Klass* ConstantPool::klass_ref_at(int which, Bytecodes::Code code, TRAPS) {
 816   return klass_at(klass_ref_index_at(which, code), THREAD);
 817 }
 818 
 819 Symbol* ConstantPool::klass_name_at(int which) const {
 820   return symbol_at(klass_slot_at(which).name_index());
 821 }
 822 
 823 Symbol* ConstantPool::klass_ref_at_noresolve(int which, Bytecodes::Code code) {
 824   jint ref_index = klass_ref_index_at(which, code);
 825   return klass_at_noresolve(ref_index);
 826 }
 827 
 828 Symbol* ConstantPool::uncached_klass_ref_at_noresolve(int which) {
 829   jint ref_index = uncached_klass_ref_index_at(which);
 830   return klass_at_noresolve(ref_index);
 831 }
 832 
 833 char* ConstantPool::string_at_noresolve(int which) {
 834   return unresolved_string_at(which)->as_C_string();
 835 }
 836 
 837 BasicType ConstantPool::basic_type_for_signature_at(int which) const {
 838   return Signature::basic_type(symbol_at(which));
 839 }
 840 
 841 
 842 void ConstantPool::resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS) {
 843   for (int index = 1; index < this_cp->length(); index++) { // Index 0 is unused
 844     if (this_cp->tag_at(index).is_string()) {
 845       this_cp->string_at(index, CHECK);
 846     }
 847   }
 848 }
 849 
 850 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception) {
 851   // Dig out the detailed message to reuse if possible
 852   Symbol* message = java_lang_Throwable::detail_message(pending_exception);
 853   if (message != nullptr) {
 854     return message;
 855   }
 856 
 857   // Return specific message for the tag
 858   switch (tag.value()) {
 859   case JVM_CONSTANT_UnresolvedClass:
 860     // return the class name in the error message
 861     message = this_cp->klass_name_at(which);
 862     break;
 863   case JVM_CONSTANT_MethodHandle:
 864     // return the method handle name in the error message
 865     message = this_cp->method_handle_name_ref_at(which);
 866     break;
 867   case JVM_CONSTANT_MethodType:
 868     // return the method type signature in the error message
 869     message = this_cp->method_type_signature_at(which);
 870     break;
 871   case JVM_CONSTANT_Dynamic:
 872     // return the name of the condy in the error message
 873     message = this_cp->uncached_name_ref_at(which);
 874     break;
 875   default:
 876     ShouldNotReachHere();
 877   }
 878 
 879   return message;
 880 }
 881 
 882 static void add_resolution_error(const constantPoolHandle& this_cp, int which,
 883                                  constantTag tag, oop pending_exception) {
 884 
 885   Symbol* error = pending_exception->klass()->name();
 886   oop cause = java_lang_Throwable::cause(pending_exception);
 887 
 888   // Also dig out the exception cause, if present.
 889   Symbol* cause_sym = nullptr;
 890   Symbol* cause_msg = nullptr;
 891   if (cause != nullptr && cause != pending_exception) {
 892     cause_sym = cause->klass()->name();
 893     cause_msg = java_lang_Throwable::detail_message(cause);
 894   }
 895 
 896   Symbol* message = exception_message(this_cp, which, tag, pending_exception);
 897   SystemDictionary::add_resolution_error(this_cp, which, error, message, cause_sym, cause_msg);
 898 }
 899 
 900 
 901 void ConstantPool::throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS) {
 902   ResourceMark rm(THREAD);
 903   Symbol* message = nullptr;
 904   Symbol* cause = nullptr;
 905   Symbol* cause_msg = nullptr;
 906   Symbol* error = SystemDictionary::find_resolution_error(this_cp, which, &message, &cause, &cause_msg);
 907   assert(error != nullptr, "checking");
 908   const char* cause_str = cause_msg != nullptr ? cause_msg->as_C_string() : nullptr;
 909 
 910   CLEAR_PENDING_EXCEPTION;
 911   if (message != nullptr) {
 912     char* msg = message->as_C_string();
 913     if (cause != nullptr) {
 914       Handle h_cause = Exceptions::new_exception(THREAD, cause, cause_str);
 915       THROW_MSG_CAUSE(error, msg, h_cause);
 916     } else {
 917       THROW_MSG(error, msg);
 918     }
 919   } else {
 920     if (cause != nullptr) {
 921       Handle h_cause = Exceptions::new_exception(THREAD, cause, cause_str);
 922       THROW_CAUSE(error, h_cause);
 923     } else {
 924       THROW(error);
 925     }
 926   }
 927 }
 928 
 929 // If resolution for Class, Dynamic constant, MethodHandle or MethodType fails, save the
 930 // exception in the resolution error table, so that the same exception is thrown again.
 931 void ConstantPool::save_and_throw_exception(const constantPoolHandle& this_cp, int which,
 932                                             constantTag tag, TRAPS) {
 933 
 934   int error_tag = tag.error_value();
 935 
 936   if (!PENDING_EXCEPTION->
 937     is_a(vmClasses::LinkageError_klass())) {
 938     // Just throw the exception and don't prevent these classes from
 939     // being loaded due to virtual machine errors like StackOverflow
 940     // and OutOfMemoryError, etc, or if the thread was hit by stop()
 941     // Needs clarification to section 5.4.3 of the VM spec (see 6308271)
 942   } else if (this_cp->tag_at(which).value() != error_tag) {
 943     add_resolution_error(this_cp, which, tag, PENDING_EXCEPTION);
 944     // CAS in the tag.  If a thread beat us to registering this error that's fine.
 945     // If another thread resolved the reference, this is a race condition. This
 946     // thread may have had a security manager or something temporary.
 947     // This doesn't deterministically get an error.   So why do we save this?
 948     // We save this because jvmti can add classes to the bootclass path after
 949     // this error, so it needs to get the same error if the error is first.
 950     jbyte old_tag = Atomic::cmpxchg((jbyte*)this_cp->tag_addr_at(which),
 951                                     (jbyte)tag.value(),
 952                                     (jbyte)error_tag);
 953     if (old_tag != error_tag && old_tag != tag.value()) {
 954       // MethodHandles and MethodType doesn't change to resolved version.
 955       assert(this_cp->tag_at(which).is_klass(), "Wrong tag value");
 956       // Forget the exception and use the resolved class.
 957       CLEAR_PENDING_EXCEPTION;
 958     }
 959   } else {
 960     // some other thread put this in error state
 961     throw_resolution_error(this_cp, which, CHECK);
 962   }
 963 }
 964 
 965 constantTag ConstantPool::constant_tag_at(int which) {
 966   constantTag tag = tag_at(which);
 967   if (tag.is_dynamic_constant()) {
 968     BasicType bt = basic_type_for_constant_at(which);
 969     return constantTag(constantTag::type2tag(bt));
 970   }
 971   return tag;
 972 }
 973 
 974 BasicType ConstantPool::basic_type_for_constant_at(int which) {
 975   constantTag tag = tag_at(which);
 976   if (tag.is_dynamic_constant() ||
 977       tag.is_dynamic_constant_in_error()) {
 978     // have to look at the signature for this one
 979     Symbol* constant_type = uncached_signature_ref_at(which);
 980     return Signature::basic_type(constant_type);
 981   }
 982   return tag.basic_type();
 983 }
 984 
 985 // Called to resolve constants in the constant pool and return an oop.
 986 // Some constant pool entries cache their resolved oop. This is also
 987 // called to create oops from constants to use in arguments for invokedynamic
 988 oop ConstantPool::resolve_constant_at_impl(const constantPoolHandle& this_cp,
 989                                            int index, int cache_index,
 990                                            bool* status_return, TRAPS) {
 991   oop result_oop = nullptr;
 992 
 993   if (cache_index == _possible_index_sentinel) {
 994     // It is possible that this constant is one which is cached in the objects.
 995     // We'll do a linear search.  This should be OK because this usage is rare.
 996     // FIXME: If bootstrap specifiers stress this code, consider putting in
 997     // a reverse index.  Binary search over a short array should do it.
 998     assert(index > 0, "valid index");
 999     cache_index = this_cp->cp_to_object_index(index);
1000   }
1001   assert(cache_index == _no_index_sentinel || cache_index >= 0, "");
1002   assert(index == _no_index_sentinel || index >= 0, "");
1003 
1004   if (cache_index >= 0) {
1005     result_oop = this_cp->resolved_reference_at(cache_index);
1006     if (result_oop != nullptr) {
1007       if (result_oop == Universe::the_null_sentinel()) {
1008         DEBUG_ONLY(int temp_index = (index >= 0 ? index : this_cp->object_to_cp_index(cache_index)));
1009         assert(this_cp->tag_at(temp_index).is_dynamic_constant(), "only condy uses the null sentinel");
1010         result_oop = nullptr;
1011       }
1012       if (status_return != nullptr)  (*status_return) = true;
1013       return result_oop;
1014       // That was easy...
1015     }
1016     index = this_cp->object_to_cp_index(cache_index);
1017   }
1018 
1019   jvalue prim_value;  // temp used only in a few cases below
1020 
1021   constantTag tag = this_cp->tag_at(index);
1022 
1023   if (status_return != nullptr) {
1024     // don't trigger resolution if the constant might need it
1025     switch (tag.value()) {
1026     case JVM_CONSTANT_Class:
1027     {
1028       CPKlassSlot kslot = this_cp->klass_slot_at(index);
1029       int resolved_klass_index = kslot.resolved_klass_index();
1030       if (this_cp->resolved_klasses()->at(resolved_klass_index) == nullptr) {
1031         (*status_return) = false;
1032         return nullptr;
1033       }
1034       // the klass is waiting in the CP; go get it
1035       break;
1036     }
1037     case JVM_CONSTANT_String:
1038     case JVM_CONSTANT_Integer:
1039     case JVM_CONSTANT_Float:
1040     case JVM_CONSTANT_Long:
1041     case JVM_CONSTANT_Double:
1042       // these guys trigger OOM at worst
1043       break;
1044     default:
1045       (*status_return) = false;
1046       return nullptr;
1047     }
1048     // from now on there is either success or an OOME
1049     (*status_return) = true;
1050   }
1051 
1052   switch (tag.value()) {
1053 
1054   case JVM_CONSTANT_UnresolvedClass:
1055   case JVM_CONSTANT_Class:
1056     {
1057       assert(cache_index == _no_index_sentinel, "should not have been set");
1058       Klass* resolved = klass_at_impl(this_cp, index, CHECK_NULL);
1059       // ldc wants the java mirror.
1060       result_oop = tag.is_Qdescriptor_klass()
1061                       ? InlineKlass::cast(resolved)->val_mirror()
1062                       : resolved->java_mirror();
1063       break;
1064     }
1065 
1066   case JVM_CONSTANT_Dynamic:
1067     {
1068       // Resolve the Dynamically-Computed constant to invoke the BSM in order to obtain the resulting oop.
1069       BootstrapInfo bootstrap_specifier(this_cp, index);
1070 
1071       // The initial step in resolving an unresolved symbolic reference to a
1072       // dynamically-computed constant is to resolve the symbolic reference to a
1073       // method handle which will be the bootstrap method for the dynamically-computed
1074       // constant. If resolution of the java.lang.invoke.MethodHandle for the bootstrap
1075       // method fails, then a MethodHandleInError is stored at the corresponding
1076       // bootstrap method's CP index for the CONSTANT_MethodHandle_info. No need to
1077       // set a DynamicConstantInError here since any subsequent use of this
1078       // bootstrap method will encounter the resolution of MethodHandleInError.
1079       // Both the first, (resolution of the BSM and its static arguments), and the second tasks,
1080       // (invocation of the BSM), of JVMS Section 5.4.3.6 occur within invoke_bootstrap_method()
1081       // for the bootstrap_specifier created above.
1082       SystemDictionary::invoke_bootstrap_method(bootstrap_specifier, THREAD);
1083       Exceptions::wrap_dynamic_exception(/* is_indy */ false, THREAD);
1084       if (HAS_PENDING_EXCEPTION) {
1085         // Resolution failure of the dynamically-computed constant, save_and_throw_exception
1086         // will check for a LinkageError and store a DynamicConstantInError.
1087         save_and_throw_exception(this_cp, index, tag, CHECK_NULL);
1088       }
1089       result_oop = bootstrap_specifier.resolved_value()();
1090       BasicType type = Signature::basic_type(bootstrap_specifier.signature());
1091       if (!is_reference_type(type)) {
1092         // Make sure the primitive value is properly boxed.
1093         // This is a JDK responsibility.
1094         const char* fail = nullptr;
1095         if (result_oop == nullptr) {
1096           fail = "null result instead of box";
1097         } else if (!is_java_primitive(type)) {
1098           // FIXME: support value types via unboxing
1099           fail = "can only handle references and primitives";
1100         } else if (!java_lang_boxing_object::is_instance(result_oop, type)) {
1101           fail = "primitive is not properly boxed";
1102         }
1103         if (fail != nullptr) {
1104           // Since this exception is not a LinkageError, throw exception
1105           // but do not save a DynamicInError resolution result.
1106           // See section 5.4.3 of the VM spec.
1107           THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), fail);
1108         }
1109       }
1110 
1111       LogTarget(Debug, methodhandles, condy) lt_condy;
1112       if (lt_condy.is_enabled()) {
1113         LogStream ls(lt_condy);
1114         bootstrap_specifier.print_msg_on(&ls, "resolve_constant_at_impl");
1115       }
1116       break;
1117     }
1118 
1119   case JVM_CONSTANT_String:
1120     assert(cache_index != _no_index_sentinel, "should have been set");
1121     result_oop = string_at_impl(this_cp, index, cache_index, CHECK_NULL);
1122     break;
1123 
1124   case JVM_CONSTANT_MethodHandle:
1125     {
1126       int ref_kind                 = this_cp->method_handle_ref_kind_at(index);
1127       int callee_index             = this_cp->method_handle_klass_index_at(index);
1128       Symbol*  name =      this_cp->method_handle_name_ref_at(index);
1129       Symbol*  signature = this_cp->method_handle_signature_ref_at(index);
1130       constantTag m_tag  = this_cp->tag_at(this_cp->method_handle_index_at(index));
1131       { ResourceMark rm(THREAD);
1132         log_debug(class, resolve)("resolve JVM_CONSTANT_MethodHandle:%d [%d/%d/%d] %s.%s",
1133                               ref_kind, index, this_cp->method_handle_index_at(index),
1134                               callee_index, name->as_C_string(), signature->as_C_string());
1135       }
1136 
1137       Klass* callee = klass_at_impl(this_cp, callee_index, THREAD);
1138       if (HAS_PENDING_EXCEPTION) {
1139         save_and_throw_exception(this_cp, index, tag, CHECK_NULL);
1140       }
1141 
1142       // Check constant pool method consistency
1143       if ((callee->is_interface() && m_tag.is_method()) ||
1144           (!callee->is_interface() && m_tag.is_interface_method())) {
1145         ResourceMark rm(THREAD);
1146         stringStream ss;
1147         ss.print("Inconsistent constant pool data in classfile for class %s. "
1148                  "Method '", callee->name()->as_C_string());
1149         signature->print_as_signature_external_return_type(&ss);
1150         ss.print(" %s(", name->as_C_string());
1151         signature->print_as_signature_external_parameters(&ss);
1152         ss.print(")' at index %d is %s and should be %s",
1153                  index,
1154                  callee->is_interface() ? "CONSTANT_MethodRef" : "CONSTANT_InterfaceMethodRef",
1155                  callee->is_interface() ? "CONSTANT_InterfaceMethodRef" : "CONSTANT_MethodRef");
1156         Exceptions::fthrow(THREAD_AND_LOCATION, vmSymbols::java_lang_IncompatibleClassChangeError(), "%s", ss.as_string());
1157         save_and_throw_exception(this_cp, index, tag, CHECK_NULL);
1158       }
1159 
1160       Klass* klass = this_cp->pool_holder();
1161       HandleMark hm(THREAD);
1162       Handle value = SystemDictionary::link_method_handle_constant(klass, ref_kind,
1163                                                                    callee, name, signature,
1164                                                                    THREAD);
1165       if (HAS_PENDING_EXCEPTION) {
1166         save_and_throw_exception(this_cp, index, tag, CHECK_NULL);
1167       }
1168       result_oop = value();
1169       break;
1170     }
1171 
1172   case JVM_CONSTANT_MethodType:
1173     {
1174       Symbol*  signature = this_cp->method_type_signature_at(index);
1175       { ResourceMark rm(THREAD);
1176         log_debug(class, resolve)("resolve JVM_CONSTANT_MethodType [%d/%d] %s",
1177                               index, this_cp->method_type_index_at(index),
1178                               signature->as_C_string());
1179       }
1180       Klass* klass = this_cp->pool_holder();
1181       HandleMark hm(THREAD);
1182       Handle value = SystemDictionary::find_method_handle_type(signature, klass, THREAD);
1183       result_oop = value();
1184       if (HAS_PENDING_EXCEPTION) {
1185         save_and_throw_exception(this_cp, index, tag, CHECK_NULL);
1186       }
1187       break;
1188     }
1189 
1190   case JVM_CONSTANT_Integer:
1191     assert(cache_index == _no_index_sentinel, "should not have been set");
1192     prim_value.i = this_cp->int_at(index);
1193     result_oop = java_lang_boxing_object::create(T_INT, &prim_value, CHECK_NULL);
1194     break;
1195 
1196   case JVM_CONSTANT_Float:
1197     assert(cache_index == _no_index_sentinel, "should not have been set");
1198     prim_value.f = this_cp->float_at(index);
1199     result_oop = java_lang_boxing_object::create(T_FLOAT, &prim_value, CHECK_NULL);
1200     break;
1201 
1202   case JVM_CONSTANT_Long:
1203     assert(cache_index == _no_index_sentinel, "should not have been set");
1204     prim_value.j = this_cp->long_at(index);
1205     result_oop = java_lang_boxing_object::create(T_LONG, &prim_value, CHECK_NULL);
1206     break;
1207 
1208   case JVM_CONSTANT_Double:
1209     assert(cache_index == _no_index_sentinel, "should not have been set");
1210     prim_value.d = this_cp->double_at(index);
1211     result_oop = java_lang_boxing_object::create(T_DOUBLE, &prim_value, CHECK_NULL);
1212     break;
1213 
1214   case JVM_CONSTANT_UnresolvedClassInError:
1215   case JVM_CONSTANT_DynamicInError:
1216   case JVM_CONSTANT_MethodHandleInError:
1217   case JVM_CONSTANT_MethodTypeInError:
1218     throw_resolution_error(this_cp, index, CHECK_NULL);
1219     break;
1220 
1221   default:
1222     fatal("unexpected constant tag at CP %p[%d/%d] = %d", this_cp(), index, cache_index, tag.value());
1223     break;
1224   }
1225 
1226   if (cache_index >= 0) {
1227     // Benign race condition:  resolved_references may already be filled in.
1228     // The important thing here is that all threads pick up the same result.
1229     // It doesn't matter which racing thread wins, as long as only one
1230     // result is used by all threads, and all future queries.
1231     oop new_result = (result_oop == nullptr ? Universe::the_null_sentinel() : result_oop);
1232     oop old_result = this_cp->set_resolved_reference_at(cache_index, new_result);
1233     if (old_result == nullptr) {
1234       return result_oop;  // was installed
1235     } else {
1236       // Return the winning thread's result.  This can be different than
1237       // the result here for MethodHandles.
1238       if (old_result == Universe::the_null_sentinel())
1239         old_result = nullptr;
1240       return old_result;
1241     }
1242   } else {
1243     assert(result_oop != Universe::the_null_sentinel(), "");
1244     return result_oop;
1245   }
1246 }
1247 
1248 oop ConstantPool::uncached_string_at(int which, TRAPS) {
1249   Symbol* sym = unresolved_string_at(which);
1250   oop str = StringTable::intern(sym, CHECK_(nullptr));
1251   assert(java_lang_String::is_instance(str), "must be string");
1252   return str;
1253 }
1254 
1255 void ConstantPool::copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int index,
1256                                                     int start_arg, int end_arg,
1257                                                     objArrayHandle info, int pos,
1258                                                     bool must_resolve, Handle if_not_available,
1259                                                     TRAPS) {
1260   int limit = pos + end_arg - start_arg;
1261   // checks: index in range [0..this_cp->length),
1262   // tag at index, start..end in range [0..this_cp->bootstrap_argument_count],
1263   // info array non-null, pos..limit in [0..info.length]
1264   if ((0 >= index    || index >= this_cp->length())  ||
1265       !(this_cp->tag_at(index).is_invoke_dynamic()    ||
1266         this_cp->tag_at(index).is_dynamic_constant()) ||
1267       (0 > start_arg || start_arg > end_arg) ||
1268       (end_arg > this_cp->bootstrap_argument_count_at(index)) ||
1269       (0 > pos       || pos > limit)         ||
1270       (info.is_null() || limit > info->length())) {
1271     // An index or something else went wrong; throw an error.
1272     // Since this is an internal API, we don't expect this,
1273     // so we don't bother to craft a nice message.
1274     THROW_MSG(vmSymbols::java_lang_LinkageError(), "bad BSM argument access");
1275   }
1276   // now we can loop safely
1277   int info_i = pos;
1278   for (int i = start_arg; i < end_arg; i++) {
1279     int arg_index = this_cp->bootstrap_argument_index_at(index, i);
1280     oop arg_oop;
1281     if (must_resolve) {
1282       arg_oop = this_cp->resolve_possibly_cached_constant_at(arg_index, CHECK);
1283     } else {
1284       bool found_it = false;
1285       arg_oop = this_cp->find_cached_constant_at(arg_index, found_it, CHECK);
1286       if (!found_it)  arg_oop = if_not_available();
1287     }
1288     info->obj_at_put(info_i++, arg_oop);
1289   }
1290 }
1291 
1292 oop ConstantPool::string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS) {
1293   // If the string has already been interned, this entry will be non-null
1294   oop str = this_cp->resolved_reference_at(obj_index);
1295   assert(str != Universe::the_null_sentinel(), "");
1296   if (str != nullptr) return str;
1297   Symbol* sym = this_cp->unresolved_string_at(which);
1298   str = StringTable::intern(sym, CHECK_(nullptr));
1299   this_cp->string_at_put(which, obj_index, str);
1300   assert(java_lang_String::is_instance(str), "must be string");
1301   return str;
1302 }
1303 
1304 
1305 bool ConstantPool::klass_name_at_matches(const InstanceKlass* k, int which) {
1306   // Names are interned, so we can compare Symbol*s directly
1307   Symbol* cp_name = klass_name_at(which);
1308   return (cp_name == k->name());
1309 }
1310 
1311 
1312 // Iterate over symbols and decrement ones which are Symbol*s
1313 // This is done during GC.
1314 // Only decrement the UTF8 symbols. Strings point to
1315 // these symbols but didn't increment the reference count.
1316 void ConstantPool::unreference_symbols() {
1317   for (int index = 1; index < length(); index++) { // Index 0 is unused
1318     constantTag tag = tag_at(index);
1319     if (tag.is_symbol()) {
1320       symbol_at(index)->decrement_refcount();
1321     }
1322   }
1323 }
1324 
1325 
1326 // Compare this constant pool's entry at index1 to the constant pool
1327 // cp2's entry at index2.
1328 bool ConstantPool::compare_entry_to(int index1, const constantPoolHandle& cp2,
1329        int index2) {
1330 
1331   // The error tags are equivalent to non-error tags when comparing
1332   jbyte t1 = tag_at(index1).non_error_value();
1333   jbyte t2 = cp2->tag_at(index2).non_error_value();
1334 
1335   if (t1 != t2) {
1336     // Not the same entry type so there is nothing else to check. Note
1337     // that this style of checking will consider resolved/unresolved
1338     // class pairs as different.
1339     // From the ConstantPool* API point of view, this is correct
1340     // behavior. See VM_RedefineClasses::merge_constant_pools() to see how this
1341     // plays out in the context of ConstantPool* merging.
1342     return false;
1343   }
1344 
1345   switch (t1) {
1346   case JVM_CONSTANT_Class:
1347   {
1348     Klass* k1 = resolved_klass_at(index1);
1349     Klass* k2 = cp2->resolved_klass_at(index2);
1350     if (k1 == k2) {
1351       return true;
1352     }
1353   } break;
1354 
1355   case JVM_CONSTANT_ClassIndex:
1356   {
1357     int recur1 = klass_index_at(index1);
1358     int recur2 = cp2->klass_index_at(index2);
1359     if (compare_entry_to(recur1, cp2, recur2)) {
1360       return true;
1361     }
1362   } break;
1363 
1364   case JVM_CONSTANT_Double:
1365   {
1366     jdouble d1 = double_at(index1);
1367     jdouble d2 = cp2->double_at(index2);
1368     if (d1 == d2) {
1369       return true;
1370     }
1371   } break;
1372 
1373   case JVM_CONSTANT_Fieldref:
1374   case JVM_CONSTANT_InterfaceMethodref:
1375   case JVM_CONSTANT_Methodref:
1376   {
1377     int recur1 = uncached_klass_ref_index_at(index1);
1378     int recur2 = cp2->uncached_klass_ref_index_at(index2);
1379     bool match = compare_entry_to(recur1, cp2, recur2);
1380     if (match) {
1381       recur1 = uncached_name_and_type_ref_index_at(index1);
1382       recur2 = cp2->uncached_name_and_type_ref_index_at(index2);
1383       if (compare_entry_to(recur1, cp2, recur2)) {
1384         return true;
1385       }
1386     }
1387   } break;
1388 
1389   case JVM_CONSTANT_Float:
1390   {
1391     jfloat f1 = float_at(index1);
1392     jfloat f2 = cp2->float_at(index2);
1393     if (f1 == f2) {
1394       return true;
1395     }
1396   } break;
1397 
1398   case JVM_CONSTANT_Integer:
1399   {
1400     jint i1 = int_at(index1);
1401     jint i2 = cp2->int_at(index2);
1402     if (i1 == i2) {
1403       return true;
1404     }
1405   } break;
1406 
1407   case JVM_CONSTANT_Long:
1408   {
1409     jlong l1 = long_at(index1);
1410     jlong l2 = cp2->long_at(index2);
1411     if (l1 == l2) {
1412       return true;
1413     }
1414   } break;
1415 
1416   case JVM_CONSTANT_NameAndType:
1417   {
1418     int recur1 = name_ref_index_at(index1);
1419     int recur2 = cp2->name_ref_index_at(index2);
1420     if (compare_entry_to(recur1, cp2, recur2)) {
1421       recur1 = signature_ref_index_at(index1);
1422       recur2 = cp2->signature_ref_index_at(index2);
1423       if (compare_entry_to(recur1, cp2, recur2)) {
1424         return true;
1425       }
1426     }
1427   } break;
1428 
1429   case JVM_CONSTANT_StringIndex:
1430   {
1431     int recur1 = string_index_at(index1);
1432     int recur2 = cp2->string_index_at(index2);
1433     if (compare_entry_to(recur1, cp2, recur2)) {
1434       return true;
1435     }
1436   } break;
1437 
1438   case JVM_CONSTANT_UnresolvedClass:
1439   {
1440     Symbol* k1 = klass_name_at(index1);
1441     Symbol* k2 = cp2->klass_name_at(index2);
1442     if (k1 == k2) {
1443       return true;
1444     }
1445   } break;
1446 
1447   case JVM_CONSTANT_MethodType:
1448   {
1449     int k1 = method_type_index_at(index1);
1450     int k2 = cp2->method_type_index_at(index2);
1451     if (compare_entry_to(k1, cp2, k2)) {
1452       return true;
1453     }
1454   } break;
1455 
1456   case JVM_CONSTANT_MethodHandle:
1457   {
1458     int k1 = method_handle_ref_kind_at(index1);
1459     int k2 = cp2->method_handle_ref_kind_at(index2);
1460     if (k1 == k2) {
1461       int i1 = method_handle_index_at(index1);
1462       int i2 = cp2->method_handle_index_at(index2);
1463       if (compare_entry_to(i1, cp2, i2)) {
1464         return true;
1465       }
1466     }
1467   } break;
1468 
1469   case JVM_CONSTANT_Dynamic:
1470   {
1471     int k1 = bootstrap_name_and_type_ref_index_at(index1);
1472     int k2 = cp2->bootstrap_name_and_type_ref_index_at(index2);
1473     int i1 = bootstrap_methods_attribute_index(index1);
1474     int i2 = cp2->bootstrap_methods_attribute_index(index2);
1475     bool match_entry = compare_entry_to(k1, cp2, k2);
1476     bool match_operand = compare_operand_to(i1, cp2, i2);
1477     return (match_entry && match_operand);
1478   } break;
1479 
1480   case JVM_CONSTANT_InvokeDynamic:
1481   {
1482     int k1 = bootstrap_name_and_type_ref_index_at(index1);
1483     int k2 = cp2->bootstrap_name_and_type_ref_index_at(index2);
1484     int i1 = bootstrap_methods_attribute_index(index1);
1485     int i2 = cp2->bootstrap_methods_attribute_index(index2);
1486     bool match_entry = compare_entry_to(k1, cp2, k2);
1487     bool match_operand = compare_operand_to(i1, cp2, i2);
1488     return (match_entry && match_operand);
1489   } break;
1490 
1491   case JVM_CONSTANT_String:
1492   {
1493     Symbol* s1 = unresolved_string_at(index1);
1494     Symbol* s2 = cp2->unresolved_string_at(index2);
1495     if (s1 == s2) {
1496       return true;
1497     }
1498   } break;
1499 
1500   case JVM_CONSTANT_Utf8:
1501   {
1502     Symbol* s1 = symbol_at(index1);
1503     Symbol* s2 = cp2->symbol_at(index2);
1504     if (s1 == s2) {
1505       return true;
1506     }
1507   } break;
1508 
1509   // Invalid is used as the tag for the second constant pool entry
1510   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
1511   // not be seen by itself.
1512   case JVM_CONSTANT_Invalid: // fall through
1513 
1514   default:
1515     ShouldNotReachHere();
1516     break;
1517   }
1518 
1519   return false;
1520 } // end compare_entry_to()
1521 
1522 
1523 // Resize the operands array with delta_len and delta_size.
1524 // Used in RedefineClasses for CP merge.
1525 void ConstantPool::resize_operands(int delta_len, int delta_size, TRAPS) {
1526   int old_len  = operand_array_length(operands());
1527   int new_len  = old_len + delta_len;
1528   int min_len  = (delta_len > 0) ? old_len : new_len;
1529 
1530   int old_size = operands()->length();
1531   int new_size = old_size + delta_size;
1532   int min_size = (delta_size > 0) ? old_size : new_size;
1533 
1534   ClassLoaderData* loader_data = pool_holder()->class_loader_data();
1535   Array<u2>* new_ops = MetadataFactory::new_array<u2>(loader_data, new_size, CHECK);
1536 
1537   // Set index in the resized array for existing elements only
1538   for (int idx = 0; idx < min_len; idx++) {
1539     int offset = operand_offset_at(idx);                       // offset in original array
1540     operand_offset_at_put(new_ops, idx, offset + 2*delta_len); // offset in resized array
1541   }
1542   // Copy the bootstrap specifiers only
1543   Copy::conjoint_memory_atomic(operands()->adr_at(2*old_len),
1544                                new_ops->adr_at(2*new_len),
1545                                (min_size - 2*min_len) * sizeof(u2));
1546   // Explicitly deallocate old operands array.
1547   // Note, it is not needed for 7u backport.
1548   if ( operands() != nullptr) { // the safety check
1549     MetadataFactory::free_array<u2>(loader_data, operands());
1550   }
1551   set_operands(new_ops);
1552 } // end resize_operands()
1553 
1554 
1555 // Extend the operands array with the length and size of the ext_cp operands.
1556 // Used in RedefineClasses for CP merge.
1557 void ConstantPool::extend_operands(const constantPoolHandle& ext_cp, TRAPS) {
1558   int delta_len = operand_array_length(ext_cp->operands());
1559   if (delta_len == 0) {
1560     return; // nothing to do
1561   }
1562   int delta_size = ext_cp->operands()->length();
1563 
1564   assert(delta_len  > 0 && delta_size > 0, "extended operands array must be bigger");
1565 
1566   if (operand_array_length(operands()) == 0) {
1567     ClassLoaderData* loader_data = pool_holder()->class_loader_data();
1568     Array<u2>* new_ops = MetadataFactory::new_array<u2>(loader_data, delta_size, CHECK);
1569     // The first element index defines the offset of second part
1570     operand_offset_at_put(new_ops, 0, 2*delta_len); // offset in new array
1571     set_operands(new_ops);
1572   } else {
1573     resize_operands(delta_len, delta_size, CHECK);
1574   }
1575 
1576 } // end extend_operands()
1577 
1578 
1579 // Shrink the operands array to a smaller array with new_len length.
1580 // Used in RedefineClasses for CP merge.
1581 void ConstantPool::shrink_operands(int new_len, TRAPS) {
1582   int old_len = operand_array_length(operands());
1583   if (new_len == old_len) {
1584     return; // nothing to do
1585   }
1586   assert(new_len < old_len, "shrunken operands array must be smaller");
1587 
1588   int free_base  = operand_next_offset_at(new_len - 1);
1589   int delta_len  = new_len - old_len;
1590   int delta_size = 2*delta_len + free_base - operands()->length();
1591 
1592   resize_operands(delta_len, delta_size, CHECK);
1593 
1594 } // end shrink_operands()
1595 
1596 
1597 void ConstantPool::copy_operands(const constantPoolHandle& from_cp,
1598                                  const constantPoolHandle& to_cp,
1599                                  TRAPS) {
1600 
1601   int from_oplen = operand_array_length(from_cp->operands());
1602   int old_oplen  = operand_array_length(to_cp->operands());
1603   if (from_oplen != 0) {
1604     ClassLoaderData* loader_data = to_cp->pool_holder()->class_loader_data();
1605     // append my operands to the target's operands array
1606     if (old_oplen == 0) {
1607       // Can't just reuse from_cp's operand list because of deallocation issues
1608       int len = from_cp->operands()->length();
1609       Array<u2>* new_ops = MetadataFactory::new_array<u2>(loader_data, len, CHECK);
1610       Copy::conjoint_memory_atomic(
1611           from_cp->operands()->adr_at(0), new_ops->adr_at(0), len * sizeof(u2));
1612       to_cp->set_operands(new_ops);
1613     } else {
1614       int old_len  = to_cp->operands()->length();
1615       int from_len = from_cp->operands()->length();
1616       int old_off  = old_oplen * sizeof(u2);
1617       int from_off = from_oplen * sizeof(u2);
1618       // Use the metaspace for the destination constant pool
1619       Array<u2>* new_operands = MetadataFactory::new_array<u2>(loader_data, old_len + from_len, CHECK);
1620       int fillp = 0, len = 0;
1621       // first part of dest
1622       Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(0),
1623                                    new_operands->adr_at(fillp),
1624                                    (len = old_off) * sizeof(u2));
1625       fillp += len;
1626       // first part of src
1627       Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(0),
1628                                    new_operands->adr_at(fillp),
1629                                    (len = from_off) * sizeof(u2));
1630       fillp += len;
1631       // second part of dest
1632       Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(old_off),
1633                                    new_operands->adr_at(fillp),
1634                                    (len = old_len - old_off) * sizeof(u2));
1635       fillp += len;
1636       // second part of src
1637       Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(from_off),
1638                                    new_operands->adr_at(fillp),
1639                                    (len = from_len - from_off) * sizeof(u2));
1640       fillp += len;
1641       assert(fillp == new_operands->length(), "");
1642 
1643       // Adjust indexes in the first part of the copied operands array.
1644       for (int j = 0; j < from_oplen; j++) {
1645         int offset = operand_offset_at(new_operands, old_oplen + j);
1646         assert(offset == operand_offset_at(from_cp->operands(), j), "correct copy");
1647         offset += old_len;  // every new tuple is preceded by old_len extra u2's
1648         operand_offset_at_put(new_operands, old_oplen + j, offset);
1649       }
1650 
1651       // replace target operands array with combined array
1652       to_cp->set_operands(new_operands);
1653     }
1654   }
1655 } // end copy_operands()
1656 
1657 
1658 // Copy this constant pool's entries at start_i to end_i (inclusive)
1659 // to the constant pool to_cp's entries starting at to_i. A total of
1660 // (end_i - start_i) + 1 entries are copied.
1661 void ConstantPool::copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i,
1662        const constantPoolHandle& to_cp, int to_i, TRAPS) {
1663 
1664 
1665   int dest_i = to_i;  // leave original alone for debug purposes
1666 
1667   for (int src_i = start_i; src_i <= end_i; /* see loop bottom */ ) {
1668     copy_entry_to(from_cp, src_i, to_cp, dest_i);
1669 
1670     switch (from_cp->tag_at(src_i).value()) {
1671     case JVM_CONSTANT_Double:
1672     case JVM_CONSTANT_Long:
1673       // double and long take two constant pool entries
1674       src_i += 2;
1675       dest_i += 2;
1676       break;
1677 
1678     default:
1679       // all others take one constant pool entry
1680       src_i++;
1681       dest_i++;
1682       break;
1683     }
1684   }
1685   copy_operands(from_cp, to_cp, CHECK);
1686 
1687 } // end copy_cp_to_impl()
1688 
1689 
1690 // Copy this constant pool's entry at from_i to the constant pool
1691 // to_cp's entry at to_i.
1692 void ConstantPool::copy_entry_to(const constantPoolHandle& from_cp, int from_i,
1693                                         const constantPoolHandle& to_cp, int to_i) {
1694 
1695   int tag = from_cp->tag_at(from_i).value();
1696   switch (tag) {
1697   case JVM_CONSTANT_ClassIndex:
1698   {
1699     jint ki = from_cp->klass_index_at(from_i);
1700     to_cp->klass_index_at_put(to_i, ki);
1701   } break;
1702 
1703   case JVM_CONSTANT_Double:
1704   {
1705     jdouble d = from_cp->double_at(from_i);
1706     to_cp->double_at_put(to_i, d);
1707     // double takes two constant pool entries so init second entry's tag
1708     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);
1709   } break;
1710 
1711   case JVM_CONSTANT_Fieldref:
1712   {
1713     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1714     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1715     to_cp->field_at_put(to_i, class_index, name_and_type_index);
1716   } break;
1717 
1718   case JVM_CONSTANT_Float:
1719   {
1720     jfloat f = from_cp->float_at(from_i);
1721     to_cp->float_at_put(to_i, f);
1722   } break;
1723 
1724   case JVM_CONSTANT_Integer:
1725   {
1726     jint i = from_cp->int_at(from_i);
1727     to_cp->int_at_put(to_i, i);
1728   } break;
1729 
1730   case JVM_CONSTANT_InterfaceMethodref:
1731   {
1732     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1733     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1734     to_cp->interface_method_at_put(to_i, class_index, name_and_type_index);
1735   } break;
1736 
1737   case JVM_CONSTANT_Long:
1738   {
1739     jlong l = from_cp->long_at(from_i);
1740     to_cp->long_at_put(to_i, l);
1741     // long takes two constant pool entries so init second entry's tag
1742     to_cp->tag_at_put(to_i + 1, JVM_CONSTANT_Invalid);
1743   } break;
1744 
1745   case JVM_CONSTANT_Methodref:
1746   {
1747     int class_index = from_cp->uncached_klass_ref_index_at(from_i);
1748     int name_and_type_index = from_cp->uncached_name_and_type_ref_index_at(from_i);
1749     to_cp->method_at_put(to_i, class_index, name_and_type_index);
1750   } break;
1751 
1752   case JVM_CONSTANT_NameAndType:
1753   {
1754     int name_ref_index = from_cp->name_ref_index_at(from_i);
1755     int signature_ref_index = from_cp->signature_ref_index_at(from_i);
1756     to_cp->name_and_type_at_put(to_i, name_ref_index, signature_ref_index);
1757   } break;
1758 
1759   case JVM_CONSTANT_StringIndex:
1760   {
1761     jint si = from_cp->string_index_at(from_i);
1762     to_cp->string_index_at_put(to_i, si);
1763   } break;
1764 
1765   case JVM_CONSTANT_Class:
1766   case JVM_CONSTANT_UnresolvedClass:
1767   case JVM_CONSTANT_UnresolvedClassInError:
1768   {
1769     // Revert to JVM_CONSTANT_ClassIndex
1770     int name_index = from_cp->klass_slot_at(from_i).name_index();
1771     assert(from_cp->tag_at(name_index).is_symbol(), "sanity");
1772     to_cp->klass_index_at_put(to_i, name_index);
1773   } break;
1774 
1775   case JVM_CONSTANT_String:
1776   {
1777     Symbol* s = from_cp->unresolved_string_at(from_i);
1778     to_cp->unresolved_string_at_put(to_i, s);
1779   } break;
1780 
1781   case JVM_CONSTANT_Utf8:
1782   {
1783     Symbol* s = from_cp->symbol_at(from_i);
1784     // Need to increase refcount, the old one will be thrown away and deferenced
1785     s->increment_refcount();
1786     to_cp->symbol_at_put(to_i, s);
1787   } break;
1788 
1789   case JVM_CONSTANT_MethodType:
1790   case JVM_CONSTANT_MethodTypeInError:
1791   {
1792     jint k = from_cp->method_type_index_at(from_i);
1793     to_cp->method_type_index_at_put(to_i, k);
1794   } break;
1795 
1796   case JVM_CONSTANT_MethodHandle:
1797   case JVM_CONSTANT_MethodHandleInError:
1798   {
1799     int k1 = from_cp->method_handle_ref_kind_at(from_i);
1800     int k2 = from_cp->method_handle_index_at(from_i);
1801     to_cp->method_handle_index_at_put(to_i, k1, k2);
1802   } break;
1803 
1804   case JVM_CONSTANT_Dynamic:
1805   case JVM_CONSTANT_DynamicInError:
1806   {
1807     int k1 = from_cp->bootstrap_methods_attribute_index(from_i);
1808     int k2 = from_cp->bootstrap_name_and_type_ref_index_at(from_i);
1809     k1 += operand_array_length(to_cp->operands());  // to_cp might already have operands
1810     to_cp->dynamic_constant_at_put(to_i, k1, k2);
1811   } break;
1812 
1813   case JVM_CONSTANT_InvokeDynamic:
1814   {
1815     int k1 = from_cp->bootstrap_methods_attribute_index(from_i);
1816     int k2 = from_cp->bootstrap_name_and_type_ref_index_at(from_i);
1817     k1 += operand_array_length(to_cp->operands());  // to_cp might already have operands
1818     to_cp->invoke_dynamic_at_put(to_i, k1, k2);
1819   } break;
1820 
1821   // Invalid is used as the tag for the second constant pool entry
1822   // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
1823   // not be seen by itself.
1824   case JVM_CONSTANT_Invalid: // fall through
1825 
1826   default:
1827   {
1828     ShouldNotReachHere();
1829   } break;
1830   }
1831 } // end copy_entry_to()
1832 
1833 // Search constant pool search_cp for an entry that matches this
1834 // constant pool's entry at pattern_i. Returns the index of a
1835 // matching entry or zero (0) if there is no matching entry.
1836 int ConstantPool::find_matching_entry(int pattern_i,
1837       const constantPoolHandle& search_cp) {
1838 
1839   // index zero (0) is not used
1840   for (int i = 1; i < search_cp->length(); i++) {
1841     bool found = compare_entry_to(pattern_i, search_cp, i);
1842     if (found) {
1843       return i;
1844     }
1845   }
1846 
1847   return 0;  // entry not found; return unused index zero (0)
1848 } // end find_matching_entry()
1849 
1850 
1851 // Compare this constant pool's bootstrap specifier at idx1 to the constant pool
1852 // cp2's bootstrap specifier at idx2.
1853 bool ConstantPool::compare_operand_to(int idx1, const constantPoolHandle& cp2, int idx2) {
1854   int k1 = operand_bootstrap_method_ref_index_at(idx1);
1855   int k2 = cp2->operand_bootstrap_method_ref_index_at(idx2);
1856   bool match = compare_entry_to(k1, cp2, k2);
1857 
1858   if (!match) {
1859     return false;
1860   }
1861   int argc = operand_argument_count_at(idx1);
1862   if (argc == cp2->operand_argument_count_at(idx2)) {
1863     for (int j = 0; j < argc; j++) {
1864       k1 = operand_argument_index_at(idx1, j);
1865       k2 = cp2->operand_argument_index_at(idx2, j);
1866       match = compare_entry_to(k1, cp2, k2);
1867       if (!match) {
1868         return false;
1869       }
1870     }
1871     return true;           // got through loop; all elements equal
1872   }
1873   return false;
1874 } // end compare_operand_to()
1875 
1876 // Search constant pool search_cp for a bootstrap specifier that matches
1877 // this constant pool's bootstrap specifier data at pattern_i index.
1878 // Return the index of a matching bootstrap attribute record or (-1) if there is no match.
1879 int ConstantPool::find_matching_operand(int pattern_i,
1880                     const constantPoolHandle& search_cp, int search_len) {
1881   for (int i = 0; i < search_len; i++) {
1882     bool found = compare_operand_to(pattern_i, search_cp, i);
1883     if (found) {
1884       return i;
1885     }
1886   }
1887   return -1;  // bootstrap specifier data not found; return unused index (-1)
1888 } // end find_matching_operand()
1889 
1890 
1891 #ifndef PRODUCT
1892 
1893 const char* ConstantPool::printable_name_at(int which) {
1894 
1895   constantTag tag = tag_at(which);
1896 
1897   if (tag.is_string()) {
1898     return string_at_noresolve(which);
1899   } else if (tag.is_klass() || tag.is_unresolved_klass()) {
1900     return klass_name_at(which)->as_C_string();
1901   } else if (tag.is_symbol()) {
1902     return symbol_at(which)->as_C_string();
1903   }
1904   return "";
1905 }
1906 
1907 #endif // PRODUCT
1908 
1909 
1910 // JVMTI GetConstantPool support
1911 
1912 // For debugging of constant pool
1913 const bool debug_cpool = false;
1914 
1915 #define DBG(code) do { if (debug_cpool) { (code); } } while(0)
1916 
1917 static void print_cpool_bytes(jint cnt, u1 *bytes) {
1918   const char* WARN_MSG = "Must not be such entry!";
1919   jint size = 0;
1920   u2   idx1, idx2;
1921 
1922   for (jint idx = 1; idx < cnt; idx++) {
1923     jint ent_size = 0;
1924     u1   tag  = *bytes++;
1925     size++;                       // count tag
1926 
1927     printf("const #%03d, tag: %02d ", idx, tag);
1928     switch(tag) {
1929       case JVM_CONSTANT_Invalid: {
1930         printf("Invalid");
1931         break;
1932       }
1933       case JVM_CONSTANT_Unicode: {
1934         printf("Unicode      %s", WARN_MSG);
1935         break;
1936       }
1937       case JVM_CONSTANT_Utf8: {
1938         u2 len = Bytes::get_Java_u2(bytes);
1939         char str[128];
1940         if (len > 127) {
1941            len = 127;
1942         }
1943         strncpy(str, (char *) (bytes+2), len);
1944         str[len] = '\0';
1945         printf("Utf8          \"%s\"", str);
1946         ent_size = 2 + len;
1947         break;
1948       }
1949       case JVM_CONSTANT_Integer: {
1950         u4 val = Bytes::get_Java_u4(bytes);
1951         printf("int          %d", *(int *) &val);
1952         ent_size = 4;
1953         break;
1954       }
1955       case JVM_CONSTANT_Float: {
1956         u4 val = Bytes::get_Java_u4(bytes);
1957         printf("float        %5.3ff", *(float *) &val);
1958         ent_size = 4;
1959         break;
1960       }
1961       case JVM_CONSTANT_Long: {
1962         u8 val = Bytes::get_Java_u8(bytes);
1963         printf("long         " INT64_FORMAT, (int64_t) *(jlong *) &val);
1964         ent_size = 8;
1965         idx++; // Long takes two cpool slots
1966         break;
1967       }
1968       case JVM_CONSTANT_Double: {
1969         u8 val = Bytes::get_Java_u8(bytes);
1970         printf("double       %5.3fd", *(jdouble *)&val);
1971         ent_size = 8;
1972         idx++; // Double takes two cpool slots
1973         break;
1974       }
1975       case JVM_CONSTANT_Class: {
1976         idx1 = Bytes::get_Java_u2(bytes);
1977         printf("class        #%03d", idx1);
1978         ent_size = 2;
1979         break;
1980       }
1981       case (JVM_CONSTANT_Class | JVM_CONSTANT_QDescBit): {
1982         idx1 = Bytes::get_Java_u2(bytes);
1983         printf("qclass        #%03d", idx1);
1984         ent_size = 2;
1985         break;
1986       }
1987       case JVM_CONSTANT_String: {
1988         idx1 = Bytes::get_Java_u2(bytes);
1989         printf("String       #%03d", idx1);
1990         ent_size = 2;
1991         break;
1992       }
1993       case JVM_CONSTANT_Fieldref: {
1994         idx1 = Bytes::get_Java_u2(bytes);
1995         idx2 = Bytes::get_Java_u2(bytes+2);
1996         printf("Field        #%03d, #%03d", (int) idx1, (int) idx2);
1997         ent_size = 4;
1998         break;
1999       }
2000       case JVM_CONSTANT_Methodref: {
2001         idx1 = Bytes::get_Java_u2(bytes);
2002         idx2 = Bytes::get_Java_u2(bytes+2);
2003         printf("Method       #%03d, #%03d", idx1, idx2);
2004         ent_size = 4;
2005         break;
2006       }
2007       case JVM_CONSTANT_InterfaceMethodref: {
2008         idx1 = Bytes::get_Java_u2(bytes);
2009         idx2 = Bytes::get_Java_u2(bytes+2);
2010         printf("InterfMethod #%03d, #%03d", idx1, idx2);
2011         ent_size = 4;
2012         break;
2013       }
2014       case JVM_CONSTANT_NameAndType: {
2015         idx1 = Bytes::get_Java_u2(bytes);
2016         idx2 = Bytes::get_Java_u2(bytes+2);
2017         printf("NameAndType  #%03d, #%03d", idx1, idx2);
2018         ent_size = 4;
2019         break;
2020       }
2021       case JVM_CONSTANT_ClassIndex: {
2022         printf("ClassIndex  %s", WARN_MSG);
2023         break;
2024       }
2025       case JVM_CONSTANT_UnresolvedClass: {
2026         printf("UnresolvedClass: %s", WARN_MSG);
2027         break;
2028       }
2029       case (JVM_CONSTANT_UnresolvedClass | JVM_CONSTANT_QDescBit): {
2030         printf("UnresolvedQClass: %s", WARN_MSG);
2031         break;
2032       }
2033       case JVM_CONSTANT_UnresolvedClassInError: {
2034         printf("UnresolvedClassInErr: %s", WARN_MSG);
2035         break;
2036       }
2037       case JVM_CONSTANT_StringIndex: {
2038         printf("StringIndex: %s", WARN_MSG);
2039         break;
2040       }
2041     }
2042     printf(";\n");
2043     bytes += ent_size;
2044     size  += ent_size;
2045   }
2046   printf("Cpool size: %d\n", size);
2047   fflush(0);
2048   return;
2049 } /* end print_cpool_bytes */
2050 
2051 
2052 // Returns size of constant pool entry.
2053 jint ConstantPool::cpool_entry_size(jint idx) {
2054   switch(tag_at(idx).value()) {
2055     case JVM_CONSTANT_Invalid:
2056     case JVM_CONSTANT_Unicode:
2057       return 1;
2058 
2059     case JVM_CONSTANT_Utf8:
2060       return 3 + symbol_at(idx)->utf8_length();
2061 
2062     case JVM_CONSTANT_Class:
2063     case JVM_CONSTANT_String:
2064     case JVM_CONSTANT_ClassIndex:
2065     case JVM_CONSTANT_UnresolvedClass:
2066     case JVM_CONSTANT_UnresolvedClassInError:
2067     case JVM_CONSTANT_StringIndex:
2068     case JVM_CONSTANT_MethodType:
2069     case JVM_CONSTANT_MethodTypeInError:
2070       return 3;
2071 
2072     case JVM_CONSTANT_MethodHandle:
2073     case JVM_CONSTANT_MethodHandleInError:
2074       return 4; //tag, ref_kind, ref_index
2075 
2076     case JVM_CONSTANT_Integer:
2077     case JVM_CONSTANT_Float:
2078     case JVM_CONSTANT_Fieldref:
2079     case JVM_CONSTANT_Methodref:
2080     case JVM_CONSTANT_InterfaceMethodref:
2081     case JVM_CONSTANT_NameAndType:
2082       return 5;
2083 
2084     case JVM_CONSTANT_Dynamic:
2085     case JVM_CONSTANT_DynamicInError:
2086     case JVM_CONSTANT_InvokeDynamic:
2087       // u1 tag, u2 bsm, u2 nt
2088       return 5;
2089 
2090     case JVM_CONSTANT_Long:
2091     case JVM_CONSTANT_Double:
2092       return 9;
2093   }
2094   assert(false, "cpool_entry_size: Invalid constant pool entry tag");
2095   return 1;
2096 } /* end cpool_entry_size */
2097 
2098 
2099 // SymbolHash is used to find a constant pool index from a string.
2100 // This function fills in SymbolHashs, one for utf8s and one for
2101 // class names, returns size of the cpool raw bytes.
2102 jint ConstantPool::hash_entries_to(SymbolHash *symmap,
2103                                    SymbolHash *classmap) {
2104   jint size = 0;
2105 
2106   for (u2 idx = 1; idx < length(); idx++) {
2107     u2 tag = tag_at(idx).value();
2108     size += cpool_entry_size(idx);
2109 
2110     switch(tag) {
2111       case JVM_CONSTANT_Utf8: {
2112         Symbol* sym = symbol_at(idx);
2113         symmap->add_if_absent(sym, idx);
2114         DBG(printf("adding symbol entry %s = %d\n", sym->as_utf8(), idx));
2115         break;
2116       }
2117       case JVM_CONSTANT_Class:
2118       case JVM_CONSTANT_UnresolvedClass:
2119       case JVM_CONSTANT_UnresolvedClassInError: {
2120         Symbol* sym = klass_name_at(idx);
2121         classmap->add_if_absent(sym, idx);
2122         DBG(printf("adding class entry %s = %d\n", sym->as_utf8(), idx));
2123         break;
2124       }
2125       case JVM_CONSTANT_Long:
2126       case JVM_CONSTANT_Double: {
2127         idx++; // Both Long and Double take two cpool slots
2128         break;
2129       }
2130     }
2131   }
2132   return size;
2133 } /* end hash_utf8_entries_to */
2134 
2135 
2136 // Copy cpool bytes.
2137 // Returns:
2138 //    0, in case of OutOfMemoryError
2139 //   -1, in case of internal error
2140 //  > 0, count of the raw cpool bytes that have been copied
2141 int ConstantPool::copy_cpool_bytes(int cpool_size,
2142                                    SymbolHash* tbl,
2143                                    unsigned char *bytes) {
2144   u2   idx1, idx2;
2145   jint size  = 0;
2146   jint cnt   = length();
2147   unsigned char *start_bytes = bytes;
2148 
2149   for (jint idx = 1; idx < cnt; idx++) {
2150     u1   tag      = tag_at(idx).value();
2151     jint ent_size = cpool_entry_size(idx);
2152 
2153     assert(size + ent_size <= cpool_size, "Size mismatch");
2154 
2155     *bytes = tag;
2156     DBG(printf("#%03hd tag=%03hd, ", (short)idx, (short)tag));
2157     switch(tag) {
2158       case JVM_CONSTANT_Invalid: {
2159         DBG(printf("JVM_CONSTANT_Invalid"));
2160         break;
2161       }
2162       case JVM_CONSTANT_Unicode: {
2163         assert(false, "Wrong constant pool tag: JVM_CONSTANT_Unicode");
2164         DBG(printf("JVM_CONSTANT_Unicode"));
2165         break;
2166       }
2167       case JVM_CONSTANT_Utf8: {
2168         Symbol* sym = symbol_at(idx);
2169         char*     str = sym->as_utf8();
2170         // Warning! It's crashing on x86 with len = sym->utf8_length()
2171         int       len = (int) strlen(str);
2172         Bytes::put_Java_u2((address) (bytes+1), (u2) len);
2173         for (int i = 0; i < len; i++) {
2174             bytes[3+i] = (u1) str[i];
2175         }
2176         DBG(printf("JVM_CONSTANT_Utf8: %s ", str));
2177         break;
2178       }
2179       case JVM_CONSTANT_Integer: {
2180         jint val = int_at(idx);
2181         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);
2182         break;
2183       }
2184       case JVM_CONSTANT_Float: {
2185         jfloat val = float_at(idx);
2186         Bytes::put_Java_u4((address) (bytes+1), *(u4*)&val);
2187         break;
2188       }
2189       case JVM_CONSTANT_Long: {
2190         jlong val = long_at(idx);
2191         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);
2192         idx++;             // Long takes two cpool slots
2193         break;
2194       }
2195       case JVM_CONSTANT_Double: {
2196         jdouble val = double_at(idx);
2197         Bytes::put_Java_u8((address) (bytes+1), *(u8*)&val);
2198         idx++;             // Double takes two cpool slots
2199         break;
2200       }
2201       case JVM_CONSTANT_Class:
2202       case JVM_CONSTANT_UnresolvedClass:
2203       case JVM_CONSTANT_UnresolvedClassInError: {
2204         *bytes = JVM_CONSTANT_Class;
2205         Symbol* sym = klass_name_at(idx);
2206         idx1 = tbl->symbol_to_value(sym);
2207         assert(idx1 != 0, "Have not found a hashtable entry");
2208         Bytes::put_Java_u2((address) (bytes+1), idx1);
2209         DBG(printf("JVM_CONSTANT_Class: idx=#%03hd, %s", idx1, sym->as_utf8()));
2210         break;
2211       }
2212       case JVM_CONSTANT_String: {
2213         *bytes = JVM_CONSTANT_String;
2214         Symbol* sym = unresolved_string_at(idx);
2215         idx1 = tbl->symbol_to_value(sym);
2216         assert(idx1 != 0, "Have not found a hashtable entry");
2217         Bytes::put_Java_u2((address) (bytes+1), idx1);
2218         DBG(printf("JVM_CONSTANT_String: idx=#%03hd, %s", idx1, sym->as_utf8()));
2219         break;
2220       }
2221       case JVM_CONSTANT_Fieldref:
2222       case JVM_CONSTANT_Methodref:
2223       case JVM_CONSTANT_InterfaceMethodref: {
2224         idx1 = uncached_klass_ref_index_at(idx);
2225         idx2 = uncached_name_and_type_ref_index_at(idx);
2226         Bytes::put_Java_u2((address) (bytes+1), idx1);
2227         Bytes::put_Java_u2((address) (bytes+3), idx2);
2228         DBG(printf("JVM_CONSTANT_Methodref: %hd %hd", idx1, idx2));
2229         break;
2230       }
2231       case JVM_CONSTANT_NameAndType: {
2232         idx1 = name_ref_index_at(idx);
2233         idx2 = signature_ref_index_at(idx);
2234         Bytes::put_Java_u2((address) (bytes+1), idx1);
2235         Bytes::put_Java_u2((address) (bytes+3), idx2);
2236         DBG(printf("JVM_CONSTANT_NameAndType: %hd %hd", idx1, idx2));
2237         break;
2238       }
2239       case JVM_CONSTANT_ClassIndex: {
2240         *bytes = JVM_CONSTANT_Class;
2241         idx1 = klass_index_at(idx);
2242         Bytes::put_Java_u2((address) (bytes+1), idx1);
2243         DBG(printf("JVM_CONSTANT_ClassIndex: %hd", idx1));
2244         break;
2245       }
2246       case JVM_CONSTANT_StringIndex: {
2247         *bytes = JVM_CONSTANT_String;
2248         idx1 = string_index_at(idx);
2249         Bytes::put_Java_u2((address) (bytes+1), idx1);
2250         DBG(printf("JVM_CONSTANT_StringIndex: %hd", idx1));
2251         break;
2252       }
2253       case JVM_CONSTANT_MethodHandle:
2254       case JVM_CONSTANT_MethodHandleInError: {
2255         *bytes = JVM_CONSTANT_MethodHandle;
2256         int kind = method_handle_ref_kind_at(idx);
2257         idx1 = method_handle_index_at(idx);
2258         *(bytes+1) = (unsigned char) kind;
2259         Bytes::put_Java_u2((address) (bytes+2), idx1);
2260         DBG(printf("JVM_CONSTANT_MethodHandle: %d %hd", kind, idx1));
2261         break;
2262       }
2263       case JVM_CONSTANT_MethodType:
2264       case JVM_CONSTANT_MethodTypeInError: {
2265         *bytes = JVM_CONSTANT_MethodType;
2266         idx1 = method_type_index_at(idx);
2267         Bytes::put_Java_u2((address) (bytes+1), idx1);
2268         DBG(printf("JVM_CONSTANT_MethodType: %hd", idx1));
2269         break;
2270       }
2271       case JVM_CONSTANT_Dynamic:
2272       case JVM_CONSTANT_DynamicInError: {
2273         *bytes = tag;
2274         idx1 = extract_low_short_from_int(*int_at_addr(idx));
2275         idx2 = extract_high_short_from_int(*int_at_addr(idx));
2276         assert(idx2 == bootstrap_name_and_type_ref_index_at(idx), "correct half of u4");
2277         Bytes::put_Java_u2((address) (bytes+1), idx1);
2278         Bytes::put_Java_u2((address) (bytes+3), idx2);
2279         DBG(printf("JVM_CONSTANT_Dynamic: %hd %hd", idx1, idx2));
2280         break;
2281       }
2282       case JVM_CONSTANT_InvokeDynamic: {
2283         *bytes = tag;
2284         idx1 = extract_low_short_from_int(*int_at_addr(idx));
2285         idx2 = extract_high_short_from_int(*int_at_addr(idx));
2286         assert(idx2 == bootstrap_name_and_type_ref_index_at(idx), "correct half of u4");
2287         Bytes::put_Java_u2((address) (bytes+1), idx1);
2288         Bytes::put_Java_u2((address) (bytes+3), idx2);
2289         DBG(printf("JVM_CONSTANT_InvokeDynamic: %hd %hd", idx1, idx2));
2290         break;
2291       }
2292     }
2293     DBG(printf("\n"));
2294     bytes += ent_size;
2295     size  += ent_size;
2296   }
2297   assert(size == cpool_size, "Size mismatch");
2298 
2299   // Keep temporarily for debugging until it's stable.
2300   DBG(print_cpool_bytes(cnt, start_bytes));
2301   return (int)(bytes - start_bytes);
2302 } /* end copy_cpool_bytes */
2303 
2304 #undef DBG
2305 
2306 bool ConstantPool::is_maybe_on_stack() const {
2307   // This method uses the similar logic as nmethod::is_maybe_on_stack()
2308   if (!Continuations::enabled()) {
2309     return false;
2310   }
2311 
2312   // If the condition below is true, it means that the nmethod was found to
2313   // be alive the previous completed marking cycle.
2314   return cache()->gc_epoch() >= CodeCache::previous_completed_gc_marking_cycle();
2315 }
2316 
2317 // For redefinition, if any methods found in loom stack chunks, the gc_epoch is
2318 // recorded in their constant pool cache. The on_stack-ness of the constant pool controls whether
2319 // memory for the method is reclaimed.
2320 bool ConstantPool::on_stack() const {
2321   if ((_flags &_on_stack) != 0) {
2322     return true;
2323   }
2324 
2325   if (_cache == nullptr) {
2326     return false;
2327   }
2328 
2329   return is_maybe_on_stack();
2330 }
2331 
2332 void ConstantPool::set_on_stack(const bool value) {
2333   if (value) {
2334     // Only record if it's not already set.
2335     if (!on_stack()) {
2336       assert(!is_shared(), "should always be set for shared constant pools");
2337       _flags |= _on_stack;
2338       MetadataOnStackMark::record(this);
2339     }
2340   } else {
2341     // Clearing is done single-threadedly.
2342     if (!is_shared()) {
2343       _flags &= ~_on_stack;
2344     }
2345   }
2346 }
2347 
2348 // Printing
2349 
2350 void ConstantPool::print_on(outputStream* st) const {
2351   assert(is_constantPool(), "must be constantPool");
2352   st->print_cr("%s", internal_name());
2353   if (flags() != 0) {
2354     st->print(" - flags: 0x%x", flags());
2355     if (has_preresolution()) st->print(" has_preresolution");
2356     if (on_stack()) st->print(" on_stack");
2357     st->cr();
2358   }
2359   if (pool_holder() != nullptr) {
2360     st->print_cr(" - holder: " PTR_FORMAT, p2i(pool_holder()));
2361   }
2362   st->print_cr(" - cache: " PTR_FORMAT, p2i(cache()));
2363   st->print_cr(" - resolved_references: " PTR_FORMAT, p2i(resolved_references_or_null()));
2364   st->print_cr(" - reference_map: " PTR_FORMAT, p2i(reference_map()));
2365   st->print_cr(" - resolved_klasses: " PTR_FORMAT, p2i(resolved_klasses()));
2366   st->print_cr(" - cp length: %d", length());
2367 
2368   for (int index = 1; index < length(); index++) {      // Index 0 is unused
2369     ((ConstantPool*)this)->print_entry_on(index, st);
2370     switch (tag_at(index).value()) {
2371       case JVM_CONSTANT_Long :
2372       case JVM_CONSTANT_Double :
2373         index++;   // Skip entry following eigth-byte constant
2374     }
2375 
2376   }
2377   st->cr();
2378 }
2379 
2380 // Print one constant pool entry
2381 void ConstantPool::print_entry_on(const int index, outputStream* st) {
2382   EXCEPTION_MARK;
2383   st->print(" - %3d : ", index);
2384   tag_at(index).print_on(st);
2385   st->print(" : ");
2386   switch (tag_at(index).value()) {
2387     case JVM_CONSTANT_Class :
2388       { Klass* k = klass_at(index, CATCH);
2389         guarantee(k != nullptr, "need klass");
2390         k->print_value_on(st);
2391         st->print(" {" PTR_FORMAT "}", p2i(k));
2392       }
2393       break;
2394     case JVM_CONSTANT_Fieldref :
2395     case JVM_CONSTANT_Methodref :
2396     case JVM_CONSTANT_InterfaceMethodref :
2397       st->print("klass_index=%d", uncached_klass_ref_index_at(index));
2398       st->print(" name_and_type_index=%d", uncached_name_and_type_ref_index_at(index));
2399       break;
2400     case JVM_CONSTANT_String :
2401       unresolved_string_at(index)->print_value_on(st);
2402       break;
2403     case JVM_CONSTANT_Integer :
2404       st->print("%d", int_at(index));
2405       break;
2406     case JVM_CONSTANT_Float :
2407       st->print("%f", float_at(index));
2408       break;
2409     case JVM_CONSTANT_Long :
2410       st->print_jlong(long_at(index));
2411       break;
2412     case JVM_CONSTANT_Double :
2413       st->print("%lf", double_at(index));
2414       break;
2415     case JVM_CONSTANT_NameAndType :
2416       st->print("name_index=%d", name_ref_index_at(index));
2417       st->print(" signature_index=%d", signature_ref_index_at(index));
2418       break;
2419     case JVM_CONSTANT_Utf8 :
2420       symbol_at(index)->print_value_on(st);
2421       break;
2422     case JVM_CONSTANT_ClassIndex: {
2423         int name_index = *int_at_addr(index);
2424         st->print("klass_index=%d ", name_index);
2425         symbol_at(name_index)->print_value_on(st);
2426       }
2427       break;
2428     case JVM_CONSTANT_UnresolvedClass :               // fall-through
2429     case JVM_CONSTANT_UnresolvedClassInError: {
2430         CPKlassSlot kslot = klass_slot_at(index);
2431         int resolved_klass_index = kslot.resolved_klass_index();
2432         int name_index = kslot.name_index();
2433         assert(tag_at(name_index).is_symbol(), "sanity");
2434         symbol_at(name_index)->print_value_on(st);
2435       }
2436       break;
2437     case JVM_CONSTANT_MethodHandle :
2438     case JVM_CONSTANT_MethodHandleInError :
2439       st->print("ref_kind=%d", method_handle_ref_kind_at(index));
2440       st->print(" ref_index=%d", method_handle_index_at(index));
2441       break;
2442     case JVM_CONSTANT_MethodType :
2443     case JVM_CONSTANT_MethodTypeInError :
2444       st->print("signature_index=%d", method_type_index_at(index));
2445       break;
2446     case JVM_CONSTANT_Dynamic :
2447     case JVM_CONSTANT_DynamicInError :
2448       {
2449         st->print("bootstrap_method_index=%d", bootstrap_method_ref_index_at(index));
2450         st->print(" type_index=%d", bootstrap_name_and_type_ref_index_at(index));
2451         int argc = bootstrap_argument_count_at(index);
2452         if (argc > 0) {
2453           for (int arg_i = 0; arg_i < argc; arg_i++) {
2454             int arg = bootstrap_argument_index_at(index, arg_i);
2455             st->print((arg_i == 0 ? " arguments={%d" : ", %d"), arg);
2456           }
2457           st->print("}");
2458         }
2459       }
2460       break;
2461     case JVM_CONSTANT_InvokeDynamic :
2462       {
2463         st->print("bootstrap_method_index=%d", bootstrap_method_ref_index_at(index));
2464         st->print(" name_and_type_index=%d", bootstrap_name_and_type_ref_index_at(index));
2465         int argc = bootstrap_argument_count_at(index);
2466         if (argc > 0) {
2467           for (int arg_i = 0; arg_i < argc; arg_i++) {
2468             int arg = bootstrap_argument_index_at(index, arg_i);
2469             st->print((arg_i == 0 ? " arguments={%d" : ", %d"), arg);
2470           }
2471           st->print("}");
2472         }
2473       }
2474       break;
2475     default:
2476       ShouldNotReachHere();
2477       break;
2478   }
2479   st->cr();
2480 }
2481 
2482 void ConstantPool::print_value_on(outputStream* st) const {
2483   assert(is_constantPool(), "must be constantPool");
2484   st->print("constant pool [%d]", length());
2485   if (has_preresolution()) st->print("/preresolution");
2486   if (operands() != nullptr)  st->print("/operands[%d]", operands()->length());
2487   print_address_on(st);
2488   if (pool_holder() != nullptr) {
2489     st->print(" for ");
2490     pool_holder()->print_value_on(st);
2491     bool extra = (pool_holder()->constants() != this);
2492     if (extra)  st->print(" (extra)");
2493   }
2494   if (cache() != nullptr) {
2495     st->print(" cache=" PTR_FORMAT, p2i(cache()));
2496   }
2497 }
2498 
2499 // Verification
2500 
2501 void ConstantPool::verify_on(outputStream* st) {
2502   guarantee(is_constantPool(), "object must be constant pool");
2503   for (int i = 0; i< length();  i++) {
2504     constantTag tag = tag_at(i);
2505     if (tag.is_klass() || tag.is_unresolved_klass()) {
2506       guarantee(klass_name_at(i)->refcount() != 0, "should have nonzero reference count");
2507     } else if (tag.is_symbol()) {
2508       Symbol* entry = symbol_at(i);
2509       guarantee(entry->refcount() != 0, "should have nonzero reference count");
2510     } else if (tag.is_string()) {
2511       Symbol* entry = unresolved_string_at(i);
2512       guarantee(entry->refcount() != 0, "should have nonzero reference count");
2513     }
2514   }
2515   if (pool_holder() != nullptr) {
2516     // Note: pool_holder() can be null in temporary constant pools
2517     // used during constant pool merging
2518     guarantee(pool_holder()->is_klass(),    "should be klass");
2519   }
2520 }