1 /*
  2  * Copyright (c) 1999, 2017, 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.inline.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 "runtime/handles.inline.hpp"
 50 #include "utilities/macros.hpp"
 51 
 52 // ciObjectFactory
 53 //
 54 // This class handles requests for the creation of new instances
 55 // of ciObject and its subclasses.  It contains a caching mechanism
 56 // which ensures that for each oop, at most one ciObject is created.
 57 // This invariant allows more efficient implementation of ciObject.
 58 //
 59 // Implementation note: the oop->ciObject mapping is represented as
 60 // a table stored in an array.  Even though objects are moved
 61 // by the garbage collector, the compactor preserves their relative
 62 // order; address comparison of oops (in perm space) is safe so long
 63 // as we prohibit GC during our comparisons.  We currently use binary
 64 // search to find the oop in the table, and inserting a new oop
 65 // into the table may be costly.  If this cost ends up being
 66 // problematic the underlying data structure can be switched to some
 67 // sort of balanced binary tree.
 68 
 69 GrowableArray<ciMetadata*>* ciObjectFactory::_shared_ci_metadata = NULL;
 70 ciSymbol*                 ciObjectFactory::_shared_ci_symbols[vmSymbols::SID_LIMIT];
 71 int                       ciObjectFactory::_shared_ident_limit = 0;
 72 volatile bool             ciObjectFactory::_initialized = false;
 73 
 74 
 75 // ------------------------------------------------------------------
 76 // ciObjectFactory::ciObjectFactory
 77 ciObjectFactory::ciObjectFactory(Arena* arena,
 78                                  int expected_size) {
 79 
 80   for (int i = 0; i < NON_PERM_BUCKETS; i++) {
 81     _non_perm_bucket[i] = NULL;
 82   }
 83   _non_perm_count = 0;
 84 
 85   _next_ident = _shared_ident_limit;
 86   _arena = arena;
 87   _ci_metadata = new (arena) GrowableArray<ciMetadata*>(arena, expected_size, 0, NULL);
 88 
 89   // If the shared ci objects exist append them to this factory's objects
 90 
 91   if (_shared_ci_metadata != NULL) {
 92     _ci_metadata->appendAll(_shared_ci_metadata);
 93   }
 94 
 95   _unloaded_methods = new (arena) GrowableArray<ciMethod*>(arena, 4, 0, NULL);
 96   _unloaded_klasses = new (arena) GrowableArray<ciKlass*>(arena, 8, 0, NULL);
 97   _unloaded_instances = new (arena) GrowableArray<ciInstance*>(arena, 4, 0, NULL);
 98   _return_addresses =
 99     new (arena) GrowableArray<ciReturnAddress*>(arena, 8, 0, NULL);
100 
101   _symbols = new (arena) GrowableArray<ciSymbol*>(arena, 100, 0, NULL);
102 }
103 
104 // ------------------------------------------------------------------
105 // ciObjectFactory::ciObjectFactory
106 void ciObjectFactory::initialize() {
107   ASSERT_IN_VM;
108   JavaThread* thread = JavaThread::current();
109   HandleMark  handle_mark(thread);
110 
111   // This Arena is long lived and exists in the resource mark of the
112   // compiler thread that initializes the initial ciObjectFactory which
113   // creates the shared ciObjects that all later ciObjectFactories use.
114   Arena* arena = new (mtCompiler) Arena(mtCompiler);
115   ciEnv initial(arena);
116   ciEnv* env = ciEnv::current();
117   env->_factory->init_shared_objects();
118 
119   _initialized = true;
120 
121 }
122 
123 void ciObjectFactory::init_shared_objects() {
124 
125   _next_ident = 1;  // start numbering CI objects at 1
126 
127   {
128     // Create the shared symbols, but not in _shared_ci_metadata.
129     int i;
130     for (i = vmSymbols::FIRST_SID; i < vmSymbols::SID_LIMIT; i++) {
131       Symbol* vmsym = vmSymbols::symbol_at((vmSymbols::SID) i);
132       assert(vmSymbols::find_sid(vmsym) == i, "1-1 mapping");
133       ciSymbol* sym = new (_arena) ciSymbol(vmsym, (vmSymbols::SID) i);
134       init_ident_of(sym);
135       _shared_ci_symbols[i] = sym;
136     }
137 #ifdef ASSERT
138     for (i = vmSymbols::FIRST_SID; i < vmSymbols::SID_LIMIT; i++) {
139       Symbol* vmsym = vmSymbols::symbol_at((vmSymbols::SID) i);
140       ciSymbol* sym = vm_symbol_at((vmSymbols::SID) i);
141       assert(sym->get_symbol() == vmsym, "oop must match");
142     }
143     assert(ciSymbol::void_class_signature()->get_symbol() == vmSymbols::void_class_signature(), "spot check");
144 #endif
145   }
146 
147   _ci_metadata = new (_arena) GrowableArray<ciMetadata*>(_arena, 64, 0, NULL);
148 
149   for (int i = T_BOOLEAN; i <= T_CONFLICT; i++) {
150     BasicType t = (BasicType)i;
151     if (type2name(t) != NULL && t != T_OBJECT && t != T_ARRAY && t != T_NARROWOOP && t != T_NARROWKLASS) {
152       ciType::_basic_types[t] = new (_arena) ciType(t);
153       init_ident_of(ciType::_basic_types[t]);
154     }
155   }
156 
157   ciEnv::_null_object_instance = new (_arena) ciNullObject();
158   init_ident_of(ciEnv::_null_object_instance);
159 
160 #define WK_KLASS_DEFN(name, ignore_s, opt)                              \
161   if (SystemDictionary::name() != NULL) \
162     ciEnv::_##name = get_metadata(SystemDictionary::name())->as_instance_klass();
163 
164   WK_KLASSES_DO(WK_KLASS_DEFN)
165 #undef WK_KLASS_DEFN
166 
167   for (int len = -1; len != _ci_metadata->length(); ) {
168     len = _ci_metadata->length();
169     for (int i2 = 0; i2 < len; i2++) {
170       ciMetadata* obj = _ci_metadata->at(i2);
171       assert (obj->is_metadata(), "what else would it be?");
172       if (obj->is_loaded() && obj->is_instance_klass()) {
173         obj->as_instance_klass()->compute_nonstatic_fields();
174       }
175     }
176   }
177 
178   ciEnv::_unloaded_cisymbol = ciObjectFactory::get_symbol(vmSymbols::dummy_symbol());
179   // Create dummy InstanceKlass and ObjArrayKlass object and assign them idents
180   ciEnv::_unloaded_ciinstance_klass = new (_arena) ciInstanceKlass(ciEnv::_unloaded_cisymbol, NULL, NULL);
181   init_ident_of(ciEnv::_unloaded_ciinstance_klass);
182   ciEnv::_unloaded_ciobjarrayklass = new (_arena) ciObjArrayKlass(ciEnv::_unloaded_cisymbol, ciEnv::_unloaded_ciinstance_klass, 1);
183   init_ident_of(ciEnv::_unloaded_ciobjarrayklass);
184   assert(ciEnv::_unloaded_ciobjarrayklass->is_obj_array_klass(), "just checking");
185 
186   get_metadata(Universe::boolArrayKlassObj());
187   get_metadata(Universe::charArrayKlassObj());
188   get_metadata(Universe::singleArrayKlassObj());
189   get_metadata(Universe::doubleArrayKlassObj());
190   get_metadata(Universe::byteArrayKlassObj());
191   get_metadata(Universe::shortArrayKlassObj());
192   get_metadata(Universe::intArrayKlassObj());
193   get_metadata(Universe::longArrayKlassObj());
194 
195 
196 
197   assert(_non_perm_count == 0, "no shared non-perm objects");
198 
199   // The shared_ident_limit is the first ident number that will
200   // be used for non-shared objects.  That is, numbers less than
201   // this limit are permanently assigned to shared CI objects,
202   // while the higher numbers are recycled afresh by each new ciEnv.
203 
204   _shared_ident_limit = _next_ident;
205   _shared_ci_metadata = _ci_metadata;
206 }
207 
208 
209 ciSymbol* ciObjectFactory::get_symbol(Symbol* key) {
210   vmSymbols::SID sid = vmSymbols::find_sid(key);
211   if (sid != vmSymbols::NO_SID) {
212     // do not pollute the main cache with it
213     return vm_symbol_at(sid);
214   }
215 
216   assert(vmSymbols::find_sid(key) == vmSymbols::NO_SID, "");
217   ciSymbol* s = new (arena()) ciSymbol(key, vmSymbols::NO_SID);
218   _symbols->push(s);
219   return s;
220 }
221 
222 // Decrement the refcount when done on symbols referenced by this compilation.
223 void ciObjectFactory::remove_symbols() {
224   for (int i = 0; i < _symbols->length(); i++) {
225     ciSymbol* s = _symbols->at(i);
226     s->get_symbol()->decrement_refcount();
227   }
228   // Since _symbols is resource allocated we're not allowed to delete it
229   // but it'll go away just the same.
230 }
231 
232 // ------------------------------------------------------------------
233 // ciObjectFactory::get
234 //
235 // Get the ciObject corresponding to some oop.  If the ciObject has
236 // already been created, it is returned.  Otherwise, a new ciObject
237 // is created.
238 ciObject* ciObjectFactory::get(oop key) {
239   ASSERT_IN_VM;
240 
241   assert(Universe::heap()->is_in_reserved(key), "must be");
242 
243   NonPermObject* &bucket = find_non_perm(key);
244   if (bucket != NULL) {
245     return bucket->object();
246   }
247 
248   // The ciObject does not yet exist.  Create it and insert it
249   // into the cache.
250   Handle keyHandle(Thread::current(), key);
251   ciObject* new_object = create_new_object(keyHandle());
252   assert(oopDesc::equals(keyHandle(), new_object->get_oop()), "must be properly recorded");
253   init_ident_of(new_object);
254   assert(Universe::heap()->is_in_reserved(new_object->get_oop()), "must be");
255 
256   // Not a perm-space object.
257   insert_non_perm(bucket, keyHandle(), new_object);
258   return new_object;
259 }
260 
261 int ciObjectFactory::metadata_compare(Metadata* const& key, ciMetadata* const& elt) {
262   Metadata* value = elt->constant_encoding();
263   if (key < value)      return -1;
264   else if (key > value) return 1;
265   else                  return 0;
266 }
267 
268 // ------------------------------------------------------------------
269 // ciObjectFactory::get_metadata
270 //
271 // Get the ciMetadata corresponding to some Metadata. If the ciMetadata has
272 // already been created, it is returned. Otherwise, a new ciMetadata
273 // is created.
274 ciMetadata* ciObjectFactory::get_metadata(Metadata* key) {
275   ASSERT_IN_VM;
276 
277 #ifdef ASSERT
278   if (CIObjectFactoryVerify) {
279     Metadata* last = NULL;
280     for (int j = 0; j< _ci_metadata->length(); j++) {
281       Metadata* o = _ci_metadata->at(j)->constant_encoding();
282       assert(last < o, "out of order");
283       last = o;
284     }
285   }
286 #endif // ASSERT
287   int len = _ci_metadata->length();
288   bool found = false;
289   int index = _ci_metadata->find_sorted<Metadata*, ciObjectFactory::metadata_compare>(key, found);
290 #ifdef ASSERT
291   if (CIObjectFactoryVerify) {
292     for (int i=0; i<_ci_metadata->length(); i++) {
293       if (_ci_metadata->at(i)->constant_encoding() == key) {
294         assert(index == i, " bad lookup");
295       }
296     }
297   }
298 #endif
299 
300   if (!found) {
301     // The ciMetadata does not yet exist. Create it and insert it
302     // into the cache.
303     ciMetadata* new_object = create_new_metadata(key);
304     init_ident_of(new_object);
305     assert(new_object->is_metadata(), "must be");
306 
307     if (len != _ci_metadata->length()) {
308       // creating the new object has recursively entered new objects
309       // into the table.  We need to recompute our index.
310       index = _ci_metadata->find_sorted<Metadata*, ciObjectFactory::metadata_compare>(key, found);
311     }
312     assert(!found, "no double insert");
313     _ci_metadata->insert_before(index, new_object);
314     return new_object;
315   }
316   return _ci_metadata->at(index)->as_metadata();
317 }
318 
319 // ------------------------------------------------------------------
320 // ciObjectFactory::create_new_object
321 //
322 // Create a new ciObject from an oop.
323 //
324 // Implementation note: this functionality could be virtual behavior
325 // of the oop itself.  For now, we explicitly marshal the object.
326 ciObject* ciObjectFactory::create_new_object(oop o) {
327   EXCEPTION_CONTEXT;
328 
329   if (o->is_instance()) {
330     instanceHandle h_i(THREAD, (instanceOop)o);
331     if (java_lang_invoke_CallSite::is_instance(o))
332       return new (arena()) ciCallSite(h_i);
333     else if (java_lang_invoke_MemberName::is_instance(o))
334       return new (arena()) ciMemberName(h_i);
335     else if (java_lang_invoke_MethodHandle::is_instance(o))
336       return new (arena()) ciMethodHandle(h_i);
337     else if (java_lang_invoke_MethodType::is_instance(o))
338       return new (arena()) ciMethodType(h_i);
339     else
340       return new (arena()) ciInstance(h_i);
341   } else if (o->is_objArray()) {
342     objArrayHandle h_oa(THREAD, (objArrayOop)o);
343     return new (arena()) ciObjArray(h_oa);
344   } else if (o->is_typeArray()) {
345     typeArrayHandle h_ta(THREAD, (typeArrayOop)o);
346     return new (arena()) ciTypeArray(h_ta);
347   }
348 
349   // The oop is of some type not supported by the compiler interface.
350   ShouldNotReachHere();
351   return NULL;
352 }
353 
354 // ------------------------------------------------------------------
355 // ciObjectFactory::create_new_metadata
356 //
357 // Create a new ciMetadata from a Metadata*.
358 //
359 // Implementation note: in order to keep Metadata live, an auxiliary ciObject
360 // is used, which points to it's holder.
361 ciMetadata* ciObjectFactory::create_new_metadata(Metadata* o) {
362   EXCEPTION_CONTEXT;
363 
364   if (o->is_klass()) {
365     Klass* k = (Klass*)o;
366     if (k->is_instance_klass()) {
367       return new (arena()) ciInstanceKlass(k);
368     } else if (k->is_objArray_klass()) {
369       return new (arena()) ciObjArrayKlass(k);
370     } else if (k->is_typeArray_klass()) {
371       return new (arena()) ciTypeArrayKlass(k);
372     }
373   } else if (o->is_method()) {
374     methodHandle h_m(THREAD, (Method*)o);
375     ciEnv *env = CURRENT_THREAD_ENV;
376     ciInstanceKlass* holder = env->get_instance_klass(h_m()->method_holder());
377     return new (arena()) ciMethod(h_m, holder);
378   } else if (o->is_methodData()) {
379     // Hold methodHandle alive - might not be necessary ???
380     methodHandle h_m(THREAD, ((MethodData*)o)->method());
381     return new (arena()) ciMethodData((MethodData*)o);
382   }
383 
384   // The Metadata* is of some type not supported by the compiler interface.
385   ShouldNotReachHere();
386   return NULL;
387 }
388 
389 //------------------------------------------------------------------
390 // ciObjectFactory::get_unloaded_method
391 //
392 // Get the ciMethod representing an unloaded/unfound method.
393 //
394 // Implementation note: unloaded methods are currently stored in
395 // an unordered array, requiring a linear-time lookup for each
396 // unloaded method.  This may need to change.
397 ciMethod* ciObjectFactory::get_unloaded_method(ciInstanceKlass* holder,
398                                                ciSymbol*        name,
399                                                ciSymbol*        signature,
400                                                ciInstanceKlass* accessor) {
401   ciSignature* that = NULL;
402   for (int i = 0; i < _unloaded_methods->length(); i++) {
403     ciMethod* entry = _unloaded_methods->at(i);
404     if (entry->holder()->equals(holder) &&
405         entry->name()->equals(name) &&
406         entry->signature()->as_symbol()->equals(signature)) {
407       // Short-circuit slow resolve.
408       if (entry->signature()->accessing_klass() == accessor) {
409         // We've found a match.
410         return entry;
411       } else {
412         // Lazily create ciSignature
413         if (that == NULL)  that = new (arena()) ciSignature(accessor, constantPoolHandle(), signature);
414         if (entry->signature()->equals(that)) {
415           // We've found a match.
416           return entry;
417         }
418       }
419     }
420   }
421 
422   // This is a new unloaded method.  Create it and stick it in
423   // the cache.
424   ciMethod* new_method = new (arena()) ciMethod(holder, name, signature, accessor);
425 
426   init_ident_of(new_method);
427   _unloaded_methods->append(new_method);
428 
429   return new_method;
430 }
431 
432 //------------------------------------------------------------------
433 // ciObjectFactory::get_unloaded_klass
434 //
435 // Get a ciKlass representing an unloaded klass.
436 //
437 // Implementation note: unloaded klasses are currently stored in
438 // an unordered array, requiring a linear-time lookup for each
439 // unloaded klass.  This may need to change.
440 ciKlass* ciObjectFactory::get_unloaded_klass(ciKlass* accessing_klass,
441                                              ciSymbol* name,
442                                              bool create_if_not_found) {
443   EXCEPTION_CONTEXT;
444   oop loader = NULL;
445   oop domain = NULL;
446   if (accessing_klass != NULL) {
447     loader = accessing_klass->loader();
448     domain = accessing_klass->protection_domain();
449   }
450   for (int i=0; i<_unloaded_klasses->length(); i++) {
451     ciKlass* entry = _unloaded_klasses->at(i);
452     if (entry->name()->equals(name) &&
453         oopDesc::equals(entry->loader(), loader) &&
454         oopDesc::equals(entry->protection_domain(), domain)) {
455       // We've found a match.
456       return entry;
457     }
458   }
459 
460   if (!create_if_not_found)
461     return NULL;
462 
463   // This is a new unloaded klass.  Create it and stick it in
464   // the cache.
465   ciKlass* new_klass = NULL;
466 
467   // Two cases: this is an unloaded ObjArrayKlass or an
468   // unloaded InstanceKlass.  Deal with both.
469   if (name->byte_at(0) == '[') {
470     // Decompose the name.'
471     FieldArrayInfo fd;
472     BasicType element_type = FieldType::get_array_info(name->get_symbol(),
473                                                        fd, THREAD);
474     if (HAS_PENDING_EXCEPTION) {
475       CLEAR_PENDING_EXCEPTION;
476       CURRENT_THREAD_ENV->record_out_of_memory_failure();
477       return ciEnv::_unloaded_ciobjarrayklass;
478     }
479     int dimension = fd.dimension();
480     assert(element_type != T_ARRAY, "unsuccessful decomposition");
481     ciKlass* element_klass = NULL;
482     if (element_type == T_OBJECT) {
483       ciEnv *env = CURRENT_THREAD_ENV;
484       ciSymbol* ci_name = env->get_symbol(fd.object_key());
485       element_klass =
486         env->get_klass_by_name(accessing_klass, ci_name, false)->as_instance_klass();
487     } else {
488       assert(dimension > 1, "one dimensional type arrays are always loaded.");
489 
490       // The type array itself takes care of one of the dimensions.
491       dimension--;
492 
493       // The element klass is a TypeArrayKlass.
494       element_klass = ciTypeArrayKlass::make(element_type);
495     }
496     new_klass = new (arena()) ciObjArrayKlass(name, element_klass, dimension);
497   } else {
498     jobject loader_handle = NULL;
499     jobject domain_handle = NULL;
500     if (accessing_klass != NULL) {
501       loader_handle = accessing_klass->loader_handle();
502       domain_handle = accessing_klass->protection_domain_handle();
503     }
504     new_klass = new (arena()) ciInstanceKlass(name, loader_handle, domain_handle);
505   }
506   init_ident_of(new_klass);
507   _unloaded_klasses->append(new_klass);
508 
509   return new_klass;
510 }
511 
512 
513 //------------------------------------------------------------------
514 // ciObjectFactory::get_unloaded_instance
515 //
516 // Get a ciInstance representing an as-yet undetermined instance of a given class.
517 //
518 ciInstance* ciObjectFactory::get_unloaded_instance(ciInstanceKlass* instance_klass) {
519   for (int i=0; i<_unloaded_instances->length(); i++) {
520     ciInstance* entry = _unloaded_instances->at(i);
521     if (entry->klass()->equals(instance_klass)) {
522       // We've found a match.
523       return entry;
524     }
525   }
526 
527   // This is a new unloaded instance.  Create it and stick it in
528   // the cache.
529   ciInstance* new_instance = new (arena()) ciInstance(instance_klass);
530 
531   init_ident_of(new_instance);
532   _unloaded_instances->append(new_instance);
533 
534   // make sure it looks the way we want:
535   assert(!new_instance->is_loaded(), "");
536   assert(new_instance->klass() == instance_klass, "");
537 
538   return new_instance;
539 }
540 
541 
542 //------------------------------------------------------------------
543 // ciObjectFactory::get_unloaded_klass_mirror
544 //
545 // Get a ciInstance representing an unresolved klass mirror.
546 //
547 // Currently, this ignores the parameters and returns a unique unloaded instance.
548 ciInstance* ciObjectFactory::get_unloaded_klass_mirror(ciKlass*  type) {
549   assert(ciEnv::_Class_klass != NULL, "");
550   return get_unloaded_instance(ciEnv::_Class_klass->as_instance_klass());
551 }
552 
553 //------------------------------------------------------------------
554 // ciObjectFactory::get_unloaded_method_handle_constant
555 //
556 // Get a ciInstance representing an unresolved method handle constant.
557 //
558 // Currently, this ignores the parameters and returns a unique unloaded instance.
559 ciInstance* ciObjectFactory::get_unloaded_method_handle_constant(ciKlass*  holder,
560                                                                  ciSymbol* name,
561                                                                  ciSymbol* signature,
562                                                                  int       ref_kind) {
563   if (ciEnv::_MethodHandle_klass == NULL)  return NULL;
564   return get_unloaded_instance(ciEnv::_MethodHandle_klass->as_instance_klass());
565 }
566 
567 //------------------------------------------------------------------
568 // ciObjectFactory::get_unloaded_method_type_constant
569 //
570 // Get a ciInstance representing an unresolved method type constant.
571 //
572 // Currently, this ignores the parameters and returns a unique unloaded instance.
573 ciInstance* ciObjectFactory::get_unloaded_method_type_constant(ciSymbol* signature) {
574   if (ciEnv::_MethodType_klass == NULL)  return NULL;
575   return get_unloaded_instance(ciEnv::_MethodType_klass->as_instance_klass());
576 }
577 
578 ciInstance* ciObjectFactory::get_unloaded_object_constant() {
579   if (ciEnv::_Object_klass == NULL)  return NULL;
580   return get_unloaded_instance(ciEnv::_Object_klass->as_instance_klass());
581 }
582 
583 //------------------------------------------------------------------
584 // ciObjectFactory::get_empty_methodData
585 //
586 // Get the ciMethodData representing the methodData for a method with
587 // none.
588 ciMethodData* ciObjectFactory::get_empty_methodData() {
589   ciMethodData* new_methodData = new (arena()) ciMethodData();
590   init_ident_of(new_methodData);
591   return new_methodData;
592 }
593 
594 //------------------------------------------------------------------
595 // ciObjectFactory::get_return_address
596 //
597 // Get a ciReturnAddress for a specified bci.
598 ciReturnAddress* ciObjectFactory::get_return_address(int bci) {
599   for (int i=0; i<_return_addresses->length(); i++) {
600     ciReturnAddress* entry = _return_addresses->at(i);
601     if (entry->bci() == bci) {
602       // We've found a match.
603       return entry;
604     }
605   }
606 
607   ciReturnAddress* new_ret_addr = new (arena()) ciReturnAddress(bci);
608   init_ident_of(new_ret_addr);
609   _return_addresses->append(new_ret_addr);
610   return new_ret_addr;
611 }
612 
613 // ------------------------------------------------------------------
614 // ciObjectFactory::init_ident_of
615 void ciObjectFactory::init_ident_of(ciBaseObject* obj) {
616   obj->set_ident(_next_ident++);
617 }
618 
619 static ciObjectFactory::NonPermObject* emptyBucket = NULL;
620 
621 // ------------------------------------------------------------------
622 // ciObjectFactory::find_non_perm
623 //
624 // Use a small hash table, hashed on the klass of the key.
625 // If there is no entry in the cache corresponding to this oop, return
626 // the null tail of the bucket into which the oop should be inserted.
627 ciObjectFactory::NonPermObject* &ciObjectFactory::find_non_perm(oop key) {
628   assert(Universe::heap()->is_in_reserved(key), "must be");
629   ciMetadata* klass = get_metadata(key->klass());
630   NonPermObject* *bp = &_non_perm_bucket[(unsigned) klass->hash() % NON_PERM_BUCKETS];
631   for (NonPermObject* p; (p = (*bp)) != NULL; bp = &p->next()) {
632     if (is_equal(p, key))  break;
633   }
634   return (*bp);
635 }
636 
637 
638 
639 // ------------------------------------------------------------------
640 // Code for for NonPermObject
641 //
642 inline ciObjectFactory::NonPermObject::NonPermObject(ciObjectFactory::NonPermObject* &bucket, oop key, ciObject* object) {
643   assert(ciObjectFactory::is_initialized(), "");
644   _object = object;
645   _next = bucket;
646   bucket = this;
647 }
648 
649 
650 
651 // ------------------------------------------------------------------
652 // ciObjectFactory::insert_non_perm
653 //
654 // Insert a ciObject into the non-perm table.
655 void ciObjectFactory::insert_non_perm(ciObjectFactory::NonPermObject* &where, oop key, ciObject* obj) {
656   assert(Universe::heap()->is_in_reserved_or_null(key), "must be");
657   assert(&where != &emptyBucket, "must not try to fill empty bucket");
658   NonPermObject* p = new (arena()) NonPermObject(where, key, obj);
659   assert(where == p && is_equal(p, key) && p->object() == obj, "entry must match");
660   assert(find_non_perm(key) == p, "must find the same spot");
661   ++_non_perm_count;
662 }
663 
664 // ------------------------------------------------------------------
665 // ciObjectFactory::vm_symbol_at
666 // Get the ciSymbol corresponding to some index in vmSymbols.
667 ciSymbol* ciObjectFactory::vm_symbol_at(int index) {
668   assert(index >= vmSymbols::FIRST_SID && index < vmSymbols::SID_LIMIT, "oob");
669   return _shared_ci_symbols[index];
670 }
671 
672 // ------------------------------------------------------------------
673 // ciObjectFactory::metadata_do
674 void ciObjectFactory::metadata_do(void f(Metadata*)) {
675   if (_ci_metadata == NULL) return;
676   for (int j = 0; j< _ci_metadata->length(); j++) {
677     Metadata* o = _ci_metadata->at(j)->constant_encoding();
678     f(o);
679   }
680 }
681 
682 // ------------------------------------------------------------------
683 // ciObjectFactory::print_contents_impl
684 void ciObjectFactory::print_contents_impl() {
685   int len = _ci_metadata->length();
686   tty->print_cr("ciObjectFactory (%d) meta data contents:", len);
687   for (int i=0; i<len; i++) {
688     _ci_metadata->at(i)->print();
689     tty->cr();
690   }
691 }
692 
693 // ------------------------------------------------------------------
694 // ciObjectFactory::print_contents
695 void ciObjectFactory::print_contents() {
696   print();
697   tty->cr();
698   GUARDED_VM_ENTRY(print_contents_impl();)
699 }
700 
701 // ------------------------------------------------------------------
702 // ciObjectFactory::print
703 //
704 // Print debugging information about the object factory
705 void ciObjectFactory::print() {
706   tty->print("<ciObjectFactory oops=%d metadata=%d unloaded_methods=%d unloaded_instances=%d unloaded_klasses=%d>",
707              _non_perm_count, _ci_metadata->length(), _unloaded_methods->length(),
708              _unloaded_instances->length(),
709              _unloaded_klasses->length());
710 }