Retain maps embedded in optimized code for several garbage collections.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 897 matching lines @@
   }
 
   return next_gc_likely_to_collect_more;
 }
 
 
 int Heap::NotifyContextDisposed(bool dependant_context) {
   if (!dependant_context) {
     tracer()->ResetSurvivalEvents();
     old_generation_size_configured_ = false;
+    set_retained_maps(ArrayList::cast(empty_fixed_array()));
   }
   if (isolate()->concurrent_recompilation_enabled()) {
     // Flush the queued recompilation tasks.
     isolate()->optimizing_compiler_thread()->Flush();
   }
   AgeInlineCaches();
   tracer()->AddContextDisposalTime(base::OS::TimeCurrentMillis());
   return ++contexts_disposed_;
 }
 
@@ skipping 2172 matching lines @@
         factory->NewTypeFeedbackVector(spec);
     dummy_vector->Set(FeedbackVectorICSlot(0),
                       *TypeFeedbackVector::MegamorphicSentinel(isolate()),
                       SKIP_WRITE_BARRIER);
     set_keyed_load_dummy_vector(*dummy_vector);
   } else {
     set_keyed_load_dummy_vector(empty_fixed_array());
   }
 
   set_detached_contexts(empty_fixed_array());
+  set_retained_maps(ArrayList::cast(empty_fixed_array()));
 
   set_weak_object_to_code_table(
       *WeakHashTable::New(isolate(), 16, USE_DEFAULT_MINIMUM_CAPACITY,
                           TENURED));
 
   Handle<SeededNumberDictionary> slow_element_dictionary =
       SeededNumberDictionary::New(isolate(), 0, TENURED);
   slow_element_dictionary->set_requires_slow_elements();
   set_empty_slow_element_dictionary(*slow_element_dictionary);
 
@@ skipping 2620 matching lines @@
 }
 
 
 DependentCode* Heap::LookupWeakObjectToCodeDependency(Handle<HeapObject> obj) {
   Object* dep = weak_object_to_code_table()->Lookup(obj);
   if (dep->IsDependentCode()) return DependentCode::cast(dep);
   return DependentCode::cast(empty_fixed_array());
 }
 
 
+void Heap::AddRetainedMap(Handle<Map> map) {
+  if (FLAG_retain_maps_for_n_gc == 0) return;
+  Handle<WeakCell> cell = Map::WeakCellForMap(map);
+  Handle<ArrayList> array(retained_maps(), isolate());
+  array = ArrayList::Add(
+      array, cell, handle(Smi::FromInt(FLAG_retain_maps_for_n_gc), isolate()));
+  if (*array != retained_maps()) {
+    set_retained_maps(*array);
+  }
+}
+
+
 void Heap::FatalProcessOutOfMemory(const char* location, bool take_snapshot) {
   v8::internal::V8::FatalProcessOutOfMemory(location, take_snapshot);
 }
 
 #ifdef DEBUG
 
 class PrintHandleVisitor : public ObjectVisitor {
  public:
   void VisitPointers(Object** start, Object** end) {
     for (Object** p = start; p < end; p++)
@@ skipping 764 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal