[turbofan] Introduce JSCallReducer to strength reduce JSCallFunction nodes.

src/type-feedback-vector.cc

 // Copyright 2014 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/type-feedback-vector.h"
 
 #include "src/code-stubs.h"
 #include "src/ic/ic.h"
 #include "src/ic/ic-state.h"
 #include "src/objects.h"
@@ skipping 502 matching lines @@
 }
 
 
 void CallICNexus::ConfigureMonomorphic(Handle<JSFunction> function) {
   Handle<WeakCell> new_cell = GetIsolate()->factory()->NewWeakCell(function);
   SetFeedback(*new_cell);
   SetFeedbackExtra(Smi::FromInt(kCallCountIncrement), SKIP_WRITE_BARRIER);
 }
 
 
+void CallICNexus::ConfigureMegamorphic() {
+  FeedbackNexus::ConfigureMegamorphic();
+}
+
+
+void CallICNexus::ConfigureMegamorphic(int call_count) {
+  SetFeedback(*TypeFeedbackVector::MegamorphicSentinel(GetIsolate()),
+              SKIP_WRITE_BARRIER);
+  SetFeedbackExtra(Smi::FromInt(call_count * kCallCountIncrement),
+                   SKIP_WRITE_BARRIER);
+}
+
+
 void LoadICNexus::ConfigureMonomorphic(Handle<Map> receiver_map,
                                        Handle<Code> handler) {
   Handle<WeakCell> cell = Map::WeakCellForMap(receiver_map);
   SetFeedback(*cell);
   SetFeedbackExtra(*handler);
 }
 
 
 void KeyedLoadICNexus::ConfigureMonomorphic(Handle<Name> name,
                                             Handle<Map> receiver_map,
@@ skipping 301 matching lines @@
   return mode;
 }
 
 
 IcCheckType KeyedStoreICNexus::GetKeyType() const {
   // The structure of the vector slots tells us the type.
   return GetFeedback()->IsName() ? PROPERTY : ELEMENT;
 }
 }  // namespace internal
 }  // namespace v8