Optimize ClearNonLiveReferences: collect dependent code only from maps that are embedded in optimize

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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 73 matching lines @@
       max_executable_size_(256ul * (kPointerSize / 4) * MB),
       // Variables set based on semispace_size_ and old_generation_size_ in
       // ConfigureHeap.
       // Will be 4 * reserved_semispace_size_ to ensure that young
       // generation can be aligned to its size.
       maximum_committed_(0),
       survived_since_last_expansion_(0),
       survived_last_scavenge_(0),
       always_allocate_scope_count_(0),
       contexts_disposed_(0),
+      number_of_disposed_maps_(0),
       global_ic_age_(0),
       scan_on_scavenge_pages_(0),
       new_space_(this),
       old_space_(NULL),
       code_space_(NULL),
       map_space_(NULL),
       lo_space_(NULL),
       gc_state_(NOT_IN_GC),
       gc_post_processing_depth_(0),
       allocations_count_(0),
@@ skipping 926 matching lines @@
     MemoryReducer::Event event;
     event.type = MemoryReducer::kContextDisposed;
     event.time_ms = MonotonicallyIncreasingTimeInMs();
     memory_reducer_->NotifyContextDisposed(event);
   }
   if (isolate()->concurrent_recompilation_enabled()) {
     // Flush the queued recompilation tasks.
     isolate()->optimizing_compile_dispatcher()->Flush();
   }
   AgeInlineCaches();
-  set_retained_maps(ArrayList::cast(empty_fixed_array()));
+  number_of_disposed_maps_ = retained_maps()->Length();
   tracer()->AddContextDisposalTime(MonotonicallyIncreasingTimeInMs());
   return ++contexts_disposed_;
 }
 
 
 void Heap::StartIncrementalMarking(int gc_flags,
                                    const GCCallbackFlags gc_callback_flags,
                                    const char* reason) {
   DCHECK(incremental_marking()->IsStopped());
   set_current_gc_flags(gc_flags);
@@ skipping 4308 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()),
       ArrayList::kReloadLengthAfterAllocation);
   if (*array != retained_maps()) {
     set_retained_maps(*array);
   }
 }
 
@@ skipping 781 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8