1 /*
   2  * Copyright (c) 1999, 2015, 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 "ci/ciCallSite.hpp"
  27 #include "ci/ciInstance.hpp"
  28 #include "ci/ciInstanceKlass.hpp"
  29 #include "ci/ciMemberName.hpp"
  30 #include "ci/ciMethod.hpp"
  31 #include "ci/ciMethodData.hpp"
  32 #include "ci/ciMethodHandle.hpp"
  33 #include "ci/ciMethodType.hpp"
  34 #include "ci/ciNullObject.hpp"
  35 #include "ci/ciObjArray.hpp"
  36 #include "ci/ciObjArrayKlass.hpp"
  37 #include "ci/ciObject.hpp"
  38 #include "ci/ciObjectFactory.hpp"
  39 #include "ci/ciSymbol.hpp"
  40 #include "ci/ciTypeArray.hpp"
  41 #include "ci/ciTypeArrayKlass.hpp"
  42 #include "ci/ciUtilities.hpp"
  43 #include "classfile/javaClasses.inline.hpp"
  44 #include "classfile/systemDictionary.hpp"
  45 #include "gc/shared/collectedHeap.inline.hpp"
  46 #include "memory/allocation.inline.hpp"
  47 #include "oops/oop.inline.hpp"
  48 #include "runtime/fieldType.hpp"
  49 #include "utilities/macros.hpp"
  50 #if INCLUDE_ALL_GCS
  51 # include "gc/shared/satbMarkQueue.hpp"
  52 #endif
  53 
  54 // ciObjectFactory
  55 //
  56 // This class handles requests for the creation of new instances
  57 // of ciObject and its subclasses.  It contains a caching mechanism
  58 // which ensures that for each oop, at most one ciObject is created.
  59 // This invariant allows more efficient implementation of ciObject.
  60 //
  61 // Implementation note: the oop->ciObject mapping is represented as
  62 // a table stored in an array.  Even though objects are moved
  63 // by the garbage collector, the compactor preserves their relative
  64 // order; address comparison of oops (in perm space) is safe so long
  65 // as we prohibit GC during our comparisons.  We currently use binary
  66 // search to find the oop in the table, and inserting a new oop
  67 // into the table may be costly.  If this cost ends up being
  68 // problematic the underlying data structure can be switched to some
  69 // sort of balanced binary tree.
  70 
  71 GrowableArray<ciMetadata*>* ciObjectFactory::_shared_ci_metadata = NULL;
  72 ciSymbol*                 ciObjectFactory::_shared_ci_symbols[vmSymbols::SID_LIMIT];
  73 int                       ciObjectFactory::_shared_ident_limit = 0;
  74 volatile bool             ciObjectFactory::_initialized = false;
  75 
  76 
  77 // ------------------------------------------------------------------
  78 // ciObjectFactory::ciObjectFactory
  79 ciObjectFactory::ciObjectFactory(Arena* arena,
  80                                  int expected_size) {
  81 
  82   for (int i = 0; i < NON_PERM_BUCKETS; i++) {
  83     _non_perm_bucket[i] = NULL;
  84   }
  85   _non_perm_count = 0;
  86 
  87   _next_ident = _shared_ident_limit;
  88   _arena = arena;
  89   _ci_metadata = new (arena) GrowableArray<ciMetadata*>(arena, expected_size, 0, NULL);
  90 
  91   // If the shared ci objects exist append them to this factory's objects
  92 
  93   if (_shared_ci_metadata != NULL) {
  94     _ci_metadata->appendAll(_shared_ci_metadata);
  95   }
  96 
  97   _unloaded_methods = new (arena) GrowableArray<ciMethod*>(arena, 4, 0, NULL);
  98   _unloaded_klasses = new (arena) GrowableArray<ciKlass*>(arena, 8, 0, NULL);
  99   _unloaded_instances = new (arena) GrowableArray<ciInstance*>(arena, 4, 0, NULL);
 100   _return_addresses =
 101     new (arena) GrowableArray<ciReturnAddress*>(arena, 8, 0, NULL);
 102 
 103   _symbols = new (arena) GrowableArray<ciSymbol*>(arena, 100, 0, NULL);
 104 }
 105 
 106 // ------------------------------------------------------------------
 107 // ciObjectFactory::ciObjectFactory
 108 void ciObjectFactory::initialize() {
 109   ASSERT_IN_VM;
 110   JavaThread* thread = JavaThread::current();
 111   HandleMark  handle_mark(thread);
 112 
 113   // This Arena is long lived and exists in the resource mark of the
 114   // compiler thread that initializes the initial ciObjectFactory which
 115   // creates the shared ciObjects that all later ciObjectFactories use.
 116   Arena* arena = new (mtCompiler) Arena(mtCompiler);
 117   ciEnv initial(arena);
 118   ciEnv* env = ciEnv::current();
 119   env->_factory->init_shared_objects();
 120 
 121   _initialized = true;
 122 
 123 }
 124 
 125 void ciObjectFactory::init_shared_objects() {
 126 
 127   _next_ident = 1;  // start numbering CI objects at 1
 128 
 129   {
 130     // Create the shared symbols, but not in _shared_ci_metadata.
 131     int i;
 132     for (i = vmSymbols::FIRST_SID; i < vmSymbols::SID_LIMIT; i++) {
 133       Symbol* vmsym = vmSymbols::symbol_at((vmSymbols::SID) i);
 134       assert(vmSymbols::find_sid(vmsym) == i, "1-1 mapping");
 135       ciSymbol* sym = new (_arena) ciSymbol(vmsym, (vmSymbols::SID) i);
 136       init_ident_of(sym);
 137       _shared_ci_symbols[i] = sym;
 138     }
 139 #ifdef ASSERT
 140     for (i = vmSymbols::FIRST_SID; i < vmSymbols::SID_LIMIT; i++) {
 141       Symbol* vmsym = vmSymbols::symbol_at((vmSymbols::SID) i);
 142       ciSymbol* sym = vm_symbol_at((vmSymbols::SID) i);
 143       assert(sym->get_symbol() == vmsym, "oop must match");
 144     }
 145     assert(ciSymbol::void_class_signature()->get_symbol() == vmSymbols::void_class_signature(), "spot check");
 146 #endif
 147   }
 148 
 149   _ci_metadata = new (_arena) GrowableArray<ciMetadata*>(_arena, 64, 0, NULL);
 150 
 151   for (int i = T_BOOLEAN; i <= T_CONFLICT; i++) {
 152     BasicType t = (BasicType)i;
 153     if (type2name(t) != NULL && t != T_OBJECT && t != T_ARRAY && t != T_NARROWOOP && t != T_NARROWKLASS) {
 154       ciType::_basic_types[t] = new (_arena) ciType(t);
 155       init_ident_of(ciType::_basic_types[t]);
 156     }
 157   }
 158 
 159   ciEnv::_null_object_instance = new (_arena) ciNullObject();
 160   init_ident_of(ciEnv::_null_object_instance);
 161 
 162 #define WK_KLASS_DEFN(name, ignore_s, opt)                              \
 163   if (SystemDictionary::name() != NULL) \
 164     ciEnv::_##name = get_metadata(SystemDictionary::name())->as_instance_klass();
 165 
 166   WK_KLASSES_DO(WK_KLASS_DEFN)
 167 #undef WK_KLASS_DEFN
 168 
 169   for (int len = -1; len != _ci_metadata->length(); ) {
 170     len = _ci_metadata->length();
 171     for (int i2 = 0; i2 < len; i2++) {
 172       ciMetadata* obj = _ci_metadata->at(i2);
 173       assert (obj->is_metadata(), "what else would it be?");
 174       if (obj->is_loaded() && obj->is_instance_klass()) {
 175         obj->as_instance_klass()->compute_nonstatic_fields();
 176       }
 177     }
 178   }
 179 
 180   ciEnv::_unloaded_cisymbol = ciObjectFactory::get_symbol(vmSymbols::dummy_symbol());
 181   // Create dummy InstanceKlass and ObjArrayKlass object and assign them idents
 182   ciEnv::_unloaded_ciinstance_klass = new (_arena) ciInstanceKlass(ciEnv::_unloaded_cisymbol, NULL, NULL);
 183   init_ident_of(ciEnv::_unloaded_ciinstance_klass);
 184   ciEnv::_unloaded_ciobjarrayklass = new (_arena) ciObjArrayKlass(ciEnv::_unloaded_cisymbol, ciEnv::_unloaded_ciinstance_klass, 1);
 185   init_ident_of(ciEnv::_unloaded_ciobjarrayklass);
 186   assert(ciEnv::_unloaded_ciobjarrayklass->is_obj_array_klass(), "just checking");
 187 
 188   get_metadata(Universe::boolArrayKlassObj());
 189   get_metadata(Universe::charArrayKlassObj());
 190   get_metadata(Universe::singleArrayKlassObj());
 191   get_metadata(Universe::doubleArrayKlassObj());
 192   get_metadata(Universe::byteArrayKlassObj());
 193   get_metadata(Universe::shortArrayKlassObj());
 194   get_metadata(Universe::intArrayKlassObj());
 195   get_metadata(Universe::longArrayKlassObj());
 196 
 197 
 198 
 199   assert(_non_perm_count == 0, "no shared non-perm objects");
 200 
 201   // The shared_ident_limit is the first ident number that will
 202   // be used for non-shared objects.  That is, numbers less than
 203   // this limit are permanently assigned to shared CI objects,
 204   // while the higher numbers are recycled afresh by each new ciEnv.
 205 
 206   _shared_ident_limit = _next_ident;
 207   _shared_ci_metadata = _ci_metadata;
 208 }
 209 
 210 
 211 ciSymbol* ciObjectFactory::get_symbol(Symbol* key) {
 212   vmSymbols::SID sid = vmSymbols::find_sid(key);
 213   if (sid != vmSymbols::NO_SID) {
 214     // do not pollute the main cache with it
 215     return vm_symbol_at(sid);
 216   }
 217 
 218   assert(vmSymbols::find_sid(key) == vmSymbols::NO_SID, "");
 219   ciSymbol* s = new (arena()) ciSymbol(key, vmSymbols::NO_SID);
 220   _symbols->push(s);
 221   return s;
 222 }
 223 
 224 // Decrement the refcount when done on symbols referenced by this compilation.
 225 void ciObjectFactory::remove_symbols() {
 226   for (int i = 0; i < _symbols->length(); i++) {
 227     ciSymbol* s = _symbols->at(i);
 228     s->get_symbol()->decrement_refcount();
 229   }
 230   // Since _symbols is resource allocated we're not allowed to delete it
 231   // but it'll go away just the same.
 232 }
 233 
 234 // ------------------------------------------------------------------
 235 // ciObjectFactory::get
 236 //
 237 // Get the ciObject corresponding to some oop.  If the ciObject has
 238 // already been created, it is returned.  Otherwise, a new ciObject
 239 // is created.
 240 ciObject* ciObjectFactory::get(oop key) {
 241   ASSERT_IN_VM;
 242 
 243   assert(Universe::heap()->is_in_reserved(key), "must be");
 244 
 245   NonPermObject* &bucket = find_non_perm(key);
 246   if (bucket != NULL) {
 247     return bucket->object();
 248   }
 249 
 250   // The ciObject does not yet exist.  Create it and insert it
 251   // into the cache.
 252   Handle keyHandle(key);
 253   ciObject* new_object = create_new_object(keyHandle());
 254   assert(keyHandle() == new_object->get_oop(), "must be properly recorded");
 255   init_ident_of(new_object);
 256   assert(Universe::heap()->is_in_reserved(new_object->get_oop()), "must be");
 257 
 258   // Not a perm-space object.
 259   insert_non_perm(bucket, keyHandle(), new_object);
 260   return new_object;
 261 }
 262 
 263 int ciObjectFactory::metadata_compare(Metadata* const& key, ciMetadata* const& elt) {
 264   Metadata* value = elt->constant_encoding();
 265   if (key < value)      return -1;
 266   else if (key > value) return 1;
 267   else                  return 0;
 268 }
 269 
 270 // ------------------------------------------------------------------
 271 // ciObjectFactory::get_metadata
 272 //
 273 // Get the ciMetadata corresponding to some Metadata. If the ciMetadata has
 274 // already been created, it is returned. Otherwise, a new ciMetadata
 275 // is created.
 276 ciMetadata* ciObjectFactory::get_metadata(Metadata* key) {
 277   ASSERT_IN_VM;
 278 
 279 #ifdef ASSERT
 280   if (CIObjectFactoryVerify) {
 281     Metadata* last = NULL;
 282     for (int j = 0; j< _ci_metadata->length(); j++) {
 283       Metadata* o = _ci_metadata->at(j)->constant_encoding();
 284       assert(last < o, "out of order");
 285       last = o;
 286     }
 287   }
 288 #endif // ASSERT
 289   int len = _ci_metadata->length();
 290   bool found = false;
 291   int index = _ci_metadata->find_sorted<Metadata*, ciObjectFactory::metadata_compare>(key, found);
 292 #ifdef ASSERT
 293   if (CIObjectFactoryVerify) {
 294     for (int i=0; i<_ci_metadata->length(); i++) {
 295       if (_ci_metadata->at(i)->constant_encoding() == key) {
 296         assert(index == i, " bad lookup");
 297       }
 298     }
 299   }
 300 #endif
 301 
 302   if (!found) {
 303     // The ciMetadata does not yet exist. Create it and insert it
 304     // into the cache.
 305     ciMetadata* new_object = create_new_metadata(key);
 306     init_ident_of(new_object);
 307     assert(new_object->is_metadata(), "must be");
 308 
 309     if (len != _ci_metadata->length()) {
 310       // creating the new object has recursively entered new objects
 311       // into the table.  We need to recompute our index.
 312       index = _ci_metadata->find_sorted<Metadata*, ciObjectFactory::metadata_compare>(key, found);
 313     }
 314     assert(!found, "no double insert");
 315     _ci_metadata->insert_before(index, new_object);
 316     return new_object;
 317   }
 318   return _ci_metadata->at(index)->as_metadata();
 319 }
 320 
 321 // ------------------------------------------------------------------
 322 // ciObjectFactory::create_new_object
 323 //
 324 // Create a new ciObject from an oop.
 325 //
 326 // Implementation note: this functionality could be virtual behavior
 327 // of the oop itself.  For now, we explicitly marshal the object.
 328 ciObject* ciObjectFactory::create_new_object(oop o) {
 329   EXCEPTION_CONTEXT;
 330 
 331   if (o->is_instance()) {
 332     instanceHandle h_i(THREAD, (instanceOop)o);
 333     if (java_lang_invoke_CallSite::is_instance(o))
 334       return new (arena()) ciCallSite(h_i);
 335     else if (java_lang_invoke_MemberName::is_instance(o))
 336       return new (arena()) ciMemberName(h_i);
 337     else if (java_lang_invoke_MethodHandle::is_instance(o))
 338       return new (arena()) ciMethodHandle(h_i);
 339     else if (java_lang_invoke_MethodType::is_instance(o))
 340       return new (arena()) ciMethodType(h_i);
 341     else
 342       return new (arena()) ciInstance(h_i);
 343   } else if (o->is_objArray()) {
 344     objArrayHandle h_oa(THREAD, (objArrayOop)o);
 345     return new (arena()) ciObjArray(h_oa);
 346   } else if (o->is_typeArray()) {
 347     typeArrayHandle h_ta(THREAD, (typeArrayOop)o);
 348     return new (arena()) ciTypeArray(h_ta);
 349   }
 350 
 351   // The oop is of some type not supported by the compiler interface.
 352   ShouldNotReachHere();
 353   return NULL;
 354 }
 355 
 356 // ------------------------------------------------------------------
 357 // ciObjectFactory::create_new_metadata
 358 //
 359 // Create a new ciMetadata from a Metadata*.
 360 //
 361 // Implementation note: in order to keep Metadata live, an auxiliary ciObject
 362 // is used, which points to it's holder.
 363 ciMetadata* ciObjectFactory::create_new_metadata(Metadata* o) {
 364   EXCEPTION_CONTEXT;
 365 
 366   // Hold metadata from unloading by keeping it's holder alive.
 367   if (_initialized && o->is_klass()) {
 368     Klass* holder = ((Klass*)o);
 369     if (holder->is_instance_klass() && InstanceKlass::cast(holder)->is_anonymous()) {
 370       // Though ciInstanceKlass records class loader oop, it's not enough to keep
 371       // VM anonymous classes alive (loader == NULL). Klass holder should be used instead.
 372       // It is enough to record a ciObject, since cached elements are never removed
 373       // during ciObjectFactory lifetime. ciObjectFactory itself is created for
 374       // every compilation and lives for the whole duration of the compilation.
 375       ciObject* h = get(holder->klass_holder());
 376     }
 377   }
 378 
 379   if (o->is_klass()) {
 380     KlassHandle h_k(THREAD, (Klass*)o);
 381     Klass* k = (Klass*)o;
 382     if (k->is_instance_klass()) {
 383       return new (arena()) ciInstanceKlass(h_k);
 384     } else if (k->is_objArray_klass()) {
 385       return new (arena()) ciObjArrayKlass(h_k);
 386     } else if (k->is_typeArray_klass()) {
 387       return new (arena()) ciTypeArrayKlass(h_k);
 388     }
 389   } else if (o->is_method()) {
 390     methodHandle h_m(THREAD, (Method*)o);
 391     ciEnv *env = CURRENT_THREAD_ENV;
 392     ciInstanceKlass* holder = env->get_instance_klass(h_m()->method_holder());
 393     return new (arena()) ciMethod(h_m, holder);
 394   } else if (o->is_methodData()) {
 395     // Hold methodHandle alive - might not be necessary ???
 396     methodHandle h_m(THREAD, ((MethodData*)o)->method());
 397     return new (arena()) ciMethodData((MethodData*)o);
 398   }
 399 
 400   // The Metadata* is of some type not supported by the compiler interface.
 401   ShouldNotReachHere();
 402   return NULL;
 403 }
 404 
 405 // ------------------------------------------------------------------
 406 // ciObjectFactory::ensure_metadata_alive
 407 //
 408 // Ensure that the metadata wrapped by the ciMetadata is kept alive by GC.
 409 // This is primarily useful for metadata which is considered as weak roots
 410 // by the GC but need to be strong roots if reachable from a current compilation.
 411 //
 412 void ciObjectFactory::ensure_metadata_alive(ciMetadata* m) {
 413   ASSERT_IN_VM; // We're handling raw oops here.
 414 
 415 #if INCLUDE_ALL_GCS
 416   if (!UseG1GC) {
 417     return;
 418   }
 419   Klass* metadata_owner_klass;
 420   if (m->is_klass()) {
 421     metadata_owner_klass = m->as_klass()->get_Klass();
 422   } else if (m->is_method()) {
 423     metadata_owner_klass = m->as_method()->get_Method()->constants()->pool_holder();
 424   } else {
 425     fatal("Not implemented for other types of metadata");
 426     return;
 427   }
 428 
 429   oop metadata_holder = metadata_owner_klass->klass_holder();
 430   if (metadata_holder != NULL) {
 431     SATBMarkQueue::enqueue(metadata_holder);
 432   }
 433 
 434 #endif
 435 }
 436 
 437 //------------------------------------------------------------------
 438 // ciObjectFactory::get_unloaded_method
 439 //
 440 // Get the ciMethod representing an unloaded/unfound method.
 441 //
 442 // Implementation note: unloaded methods are currently stored in
 443 // an unordered array, requiring a linear-time lookup for each
 444 // unloaded method.  This may need to change.
 445 ciMethod* ciObjectFactory::get_unloaded_method(ciInstanceKlass* holder,
 446                                                ciSymbol*        name,
 447                                                ciSymbol*        signature,
 448                                                ciInstanceKlass* accessor) {
 449   ciSignature* that = NULL;
 450   for (int i = 0; i < _unloaded_methods->length(); i++) {
 451     ciMethod* entry = _unloaded_methods->at(i);
 452     if (entry->holder()->equals(holder) &&
 453         entry->name()->equals(name) &&
 454         entry->signature()->as_symbol()->equals(signature)) {
 455       // Short-circuit slow resolve.
 456       if (entry->signature()->accessing_klass() == accessor) {
 457         // We've found a match.
 458         return entry;
 459       } else {
 460         // Lazily create ciSignature
 461         if (that == NULL)  that = new (arena()) ciSignature(accessor, constantPoolHandle(), signature);
 462         if (entry->signature()->equals(that)) {
 463           // We've found a match.
 464           return entry;
 465         }
 466       }
 467     }
 468   }
 469 
 470   // This is a new unloaded method.  Create it and stick it in
 471   // the cache.
 472   ciMethod* new_method = new (arena()) ciMethod(holder, name, signature, accessor);
 473 
 474   init_ident_of(new_method);
 475   _unloaded_methods->append(new_method);
 476 
 477   return new_method;
 478 }
 479 
 480 //------------------------------------------------------------------
 481 // ciObjectFactory::get_unloaded_klass
 482 //
 483 // Get a ciKlass representing an unloaded klass.
 484 //
 485 // Implementation note: unloaded klasses are currently stored in
 486 // an unordered array, requiring a linear-time lookup for each
 487 // unloaded klass.  This may need to change.
 488 ciKlass* ciObjectFactory::get_unloaded_klass(ciKlass* accessing_klass,
 489                                              ciSymbol* name,
 490                                              bool create_if_not_found) {
 491   EXCEPTION_CONTEXT;
 492   oop loader = NULL;
 493   oop domain = NULL;
 494   if (accessing_klass != NULL) {
 495     loader = accessing_klass->loader();
 496     domain = accessing_klass->protection_domain();
 497   }
 498   for (int i=0; i<_unloaded_klasses->length(); i++) {
 499     ciKlass* entry = _unloaded_klasses->at(i);
 500     if (entry->name()->equals(name) &&
 501         entry->loader() == loader &&
 502         entry->protection_domain() == domain) {
 503       // We've found a match.
 504       return entry;
 505     }
 506   }
 507 
 508   if (!create_if_not_found)
 509     return NULL;
 510 
 511   // This is a new unloaded klass.  Create it and stick it in
 512   // the cache.
 513   ciKlass* new_klass = NULL;
 514 
 515   // Two cases: this is an unloaded ObjArrayKlass or an
 516   // unloaded InstanceKlass.  Deal with both.
 517   if (name->byte_at(0) == '[') {
 518     // Decompose the name.'
 519     FieldArrayInfo fd;
 520     BasicType element_type = FieldType::get_array_info(name->get_symbol(),
 521                                                        fd, THREAD);
 522     if (HAS_PENDING_EXCEPTION) {
 523       CLEAR_PENDING_EXCEPTION;
 524       CURRENT_THREAD_ENV->record_out_of_memory_failure();
 525       return ciEnv::_unloaded_ciobjarrayklass;
 526     }
 527     int dimension = fd.dimension();
 528     assert(element_type != T_ARRAY, "unsuccessful decomposition");
 529     ciKlass* element_klass = NULL;
 530     if (element_type == T_OBJECT) {
 531       ciEnv *env = CURRENT_THREAD_ENV;
 532       ciSymbol* ci_name = env->get_symbol(fd.object_key());
 533       element_klass =
 534         env->get_klass_by_name(accessing_klass, ci_name, false)->as_instance_klass();
 535     } else {
 536       assert(dimension > 1, "one dimensional type arrays are always loaded.");
 537 
 538       // The type array itself takes care of one of the dimensions.
 539       dimension--;
 540 
 541       // The element klass is a TypeArrayKlass.
 542       element_klass = ciTypeArrayKlass::make(element_type);
 543     }
 544     new_klass = new (arena()) ciObjArrayKlass(name, element_klass, dimension);
 545   } else {
 546     jobject loader_handle = NULL;
 547     jobject domain_handle = NULL;
 548     if (accessing_klass != NULL) {
 549       loader_handle = accessing_klass->loader_handle();
 550       domain_handle = accessing_klass->protection_domain_handle();
 551     }
 552     new_klass = new (arena()) ciInstanceKlass(name, loader_handle, domain_handle);
 553   }
 554   init_ident_of(new_klass);
 555   _unloaded_klasses->append(new_klass);
 556 
 557   return new_klass;
 558 }
 559 
 560 
 561 //------------------------------------------------------------------
 562 // ciObjectFactory::get_unloaded_instance
 563 //
 564 // Get a ciInstance representing an as-yet undetermined instance of a given class.
 565 //
 566 ciInstance* ciObjectFactory::get_unloaded_instance(ciInstanceKlass* instance_klass) {
 567   for (int i=0; i<_unloaded_instances->length(); i++) {
 568     ciInstance* entry = _unloaded_instances->at(i);
 569     if (entry->klass()->equals(instance_klass)) {
 570       // We've found a match.
 571       return entry;
 572     }
 573   }
 574 
 575   // This is a new unloaded instance.  Create it and stick it in
 576   // the cache.
 577   ciInstance* new_instance = new (arena()) ciInstance(instance_klass);
 578 
 579   init_ident_of(new_instance);
 580   _unloaded_instances->append(new_instance);
 581 
 582   // make sure it looks the way we want:
 583   assert(!new_instance->is_loaded(), "");
 584   assert(new_instance->klass() == instance_klass, "");
 585 
 586   return new_instance;
 587 }
 588 
 589 
 590 //------------------------------------------------------------------
 591 // ciObjectFactory::get_unloaded_klass_mirror
 592 //
 593 // Get a ciInstance representing an unresolved klass mirror.
 594 //
 595 // Currently, this ignores the parameters and returns a unique unloaded instance.
 596 ciInstance* ciObjectFactory::get_unloaded_klass_mirror(ciKlass*  type) {
 597   assert(ciEnv::_Class_klass != NULL, "");
 598   return get_unloaded_instance(ciEnv::_Class_klass->as_instance_klass());
 599 }
 600 
 601 //------------------------------------------------------------------
 602 // ciObjectFactory::get_unloaded_method_handle_constant
 603 //
 604 // Get a ciInstance representing an unresolved method handle constant.
 605 //
 606 // Currently, this ignores the parameters and returns a unique unloaded instance.
 607 ciInstance* ciObjectFactory::get_unloaded_method_handle_constant(ciKlass*  holder,
 608                                                                  ciSymbol* name,
 609                                                                  ciSymbol* signature,
 610                                                                  int       ref_kind) {
 611   if (ciEnv::_MethodHandle_klass == NULL)  return NULL;
 612   return get_unloaded_instance(ciEnv::_MethodHandle_klass->as_instance_klass());
 613 }
 614 
 615 //------------------------------------------------------------------
 616 // ciObjectFactory::get_unloaded_method_type_constant
 617 //
 618 // Get a ciInstance representing an unresolved method type constant.
 619 //
 620 // Currently, this ignores the parameters and returns a unique unloaded instance.
 621 ciInstance* ciObjectFactory::get_unloaded_method_type_constant(ciSymbol* signature) {
 622   if (ciEnv::_MethodType_klass == NULL)  return NULL;
 623   return get_unloaded_instance(ciEnv::_MethodType_klass->as_instance_klass());
 624 }
 625 
 626 ciInstance* ciObjectFactory::get_unloaded_object_constant() {
 627   if (ciEnv::_Object_klass == NULL)  return NULL;
 628   return get_unloaded_instance(ciEnv::_Object_klass->as_instance_klass());
 629 }
 630 
 631 //------------------------------------------------------------------
 632 // ciObjectFactory::get_empty_methodData
 633 //
 634 // Get the ciMethodData representing the methodData for a method with
 635 // none.
 636 ciMethodData* ciObjectFactory::get_empty_methodData() {
 637   ciMethodData* new_methodData = new (arena()) ciMethodData();
 638   init_ident_of(new_methodData);
 639   return new_methodData;
 640 }
 641 
 642 //------------------------------------------------------------------
 643 // ciObjectFactory::get_return_address
 644 //
 645 // Get a ciReturnAddress for a specified bci.
 646 ciReturnAddress* ciObjectFactory::get_return_address(int bci) {
 647   for (int i=0; i<_return_addresses->length(); i++) {
 648     ciReturnAddress* entry = _return_addresses->at(i);
 649     if (entry->bci() == bci) {
 650       // We've found a match.
 651       return entry;
 652     }
 653   }
 654 
 655   ciReturnAddress* new_ret_addr = new (arena()) ciReturnAddress(bci);
 656   init_ident_of(new_ret_addr);
 657   _return_addresses->append(new_ret_addr);
 658   return new_ret_addr;
 659 }
 660 
 661 // ------------------------------------------------------------------
 662 // ciObjectFactory::init_ident_of
 663 void ciObjectFactory::init_ident_of(ciBaseObject* obj) {
 664   obj->set_ident(_next_ident++);
 665 }
 666 
 667 static ciObjectFactory::NonPermObject* emptyBucket = NULL;
 668 
 669 // ------------------------------------------------------------------
 670 // ciObjectFactory::find_non_perm
 671 //
 672 // Use a small hash table, hashed on the klass of the key.
 673 // If there is no entry in the cache corresponding to this oop, return
 674 // the null tail of the bucket into which the oop should be inserted.
 675 ciObjectFactory::NonPermObject* &ciObjectFactory::find_non_perm(oop key) {
 676   assert(Universe::heap()->is_in_reserved(key), "must be");
 677   ciMetadata* klass = get_metadata(key->klass());
 678   NonPermObject* *bp = &_non_perm_bucket[(unsigned) klass->hash() % NON_PERM_BUCKETS];
 679   for (NonPermObject* p; (p = (*bp)) != NULL; bp = &p->next()) {
 680     if (is_equal(p, key))  break;
 681   }
 682   return (*bp);
 683 }
 684 
 685 
 686 
 687 // ------------------------------------------------------------------
 688 // Code for for NonPermObject
 689 //
 690 inline ciObjectFactory::NonPermObject::NonPermObject(ciObjectFactory::NonPermObject* &bucket, oop key, ciObject* object) {
 691   assert(ciObjectFactory::is_initialized(), "");
 692   _object = object;
 693   _next = bucket;
 694   bucket = this;
 695 }
 696 
 697 
 698 
 699 // ------------------------------------------------------------------
 700 // ciObjectFactory::insert_non_perm
 701 //
 702 // Insert a ciObject into the non-perm table.
 703 void ciObjectFactory::insert_non_perm(ciObjectFactory::NonPermObject* &where, oop key, ciObject* obj) {
 704   assert(Universe::heap()->is_in_reserved_or_null(key), "must be");
 705   assert(&where != &emptyBucket, "must not try to fill empty bucket");
 706   NonPermObject* p = new (arena()) NonPermObject(where, key, obj);
 707   assert(where == p && is_equal(p, key) && p->object() == obj, "entry must match");
 708   assert(find_non_perm(key) == p, "must find the same spot");
 709   ++_non_perm_count;
 710 }
 711 
 712 // ------------------------------------------------------------------
 713 // ciObjectFactory::vm_symbol_at
 714 // Get the ciSymbol corresponding to some index in vmSymbols.
 715 ciSymbol* ciObjectFactory::vm_symbol_at(int index) {
 716   assert(index >= vmSymbols::FIRST_SID && index < vmSymbols::SID_LIMIT, "oob");
 717   return _shared_ci_symbols[index];
 718 }
 719 
 720 // ------------------------------------------------------------------
 721 // ciObjectFactory::metadata_do
 722 void ciObjectFactory::metadata_do(void f(Metadata*)) {
 723   if (_ci_metadata == NULL) return;
 724   for (int j = 0; j< _ci_metadata->length(); j++) {
 725     Metadata* o = _ci_metadata->at(j)->constant_encoding();
 726     f(o);
 727   }
 728 }
 729 
 730 // ------------------------------------------------------------------
 731 // ciObjectFactory::print_contents_impl
 732 void ciObjectFactory::print_contents_impl() {
 733   int len = _ci_metadata->length();
 734   tty->print_cr("ciObjectFactory (%d) meta data contents:", len);
 735   for (int i=0; i<len; i++) {
 736     _ci_metadata->at(i)->print();
 737     tty->cr();
 738   }
 739 }
 740 
 741 // ------------------------------------------------------------------
 742 // ciObjectFactory::print_contents
 743 void ciObjectFactory::print_contents() {
 744   print();
 745   tty->cr();
 746   GUARDED_VM_ENTRY(print_contents_impl();)
 747 }
 748 
 749 // ------------------------------------------------------------------
 750 // ciObjectFactory::print
 751 //
 752 // Print debugging information about the object factory
 753 void ciObjectFactory::print() {
 754   tty->print("<ciObjectFactory oops=%d metadata=%d unloaded_methods=%d unloaded_instances=%d unloaded_klasses=%d>",
 755              _non_perm_count, _ci_metadata->length(), _unloaded_methods->length(),
 756              _unloaded_instances->length(),
 757              _unloaded_klasses->length());
 758 }