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