Do not look for the slot in the ScopeInfo's global range when it's not necessary.

src/scopeinfo.h

Index: src/scopeinfo.h
diff --git a/src/scopeinfo.h b/src/scopeinfo.h
index adefaef9741d56d82f5cef62d05bc687baaa8bf7..70a17cd7d4a945975ce7ed59f7dc73c9d42d569c 100644
--- a/src/scopeinfo.h
+++ b/src/scopeinfo.h
@@ -21,12 +21,12 @@ class ContextSlotCache {
   // Lookup context slot index for (data, name).
   // If absent, kNotFound is returned.
   int Lookup(Object* data, String* name, VariableMode* mode,
-             VariableLocation* location, InitializationFlag* init_flag,
+             InitializationFlag* init_flag,
              MaybeAssignedFlag* maybe_assigned_flag);
 
   // Update an element in the cache.
   void Update(Handle<Object> data, Handle<String> name, VariableMode mode,
-              VariableLocation location, InitializationFlag init_flag,
+              InitializationFlag init_flag,
               MaybeAssignedFlag maybe_assigned_flag, int slot_index);
 
   // Clear the cache.
@@ -47,8 +47,7 @@ class ContextSlotCache {
 
 #ifdef DEBUG
   void ValidateEntry(Handle<Object> data, Handle<String> name,
-                     VariableMode mode, VariableLocation location,
-                     InitializationFlag init_flag,
+                     VariableMode mode, InitializationFlag init_flag,
                      MaybeAssignedFlag maybe_assigned_flag, int slot_index);
 #endif
 
@@ -59,26 +58,16 @@ class ContextSlotCache {
   };
 
   struct Value {
-    enum VariableLocationFlag { kContext, kGlobal };
-
-    Value(VariableMode mode, VariableLocation location,
-          InitializationFlag init_flag, MaybeAssignedFlag maybe_assigned_flag,
-          int index) {
-      DCHECK(location == VariableLocation::CONTEXT ||
-             location == VariableLocation::GLOBAL);
-      VariableLocationFlag location_flag =
-          location == VariableLocation::CONTEXT ? kContext : kGlobal;
+    Value(VariableMode mode, InitializationFlag init_flag,
+          MaybeAssignedFlag maybe_assigned_flag, int index) {
       DCHECK(ModeField::is_valid(mode));
-      DCHECK(VariableLocationField::is_valid(location_flag));
       DCHECK(InitField::is_valid(init_flag));
       DCHECK(MaybeAssignedField::is_valid(maybe_assigned_flag));
       DCHECK(IndexField::is_valid(index));
       value_ = ModeField::encode(mode) | IndexField::encode(index) |
-               VariableLocationField::encode(location_flag) |
                InitField::encode(init_flag) |
                MaybeAssignedField::encode(maybe_assigned_flag);
       DCHECK(mode == this->mode());
-      DCHECK(location == this->location());
       DCHECK(init_flag == this->initialization_flag());
       DCHECK(maybe_assigned_flag == this->maybe_assigned_flag());
       DCHECK(index == this->index());
@@ -90,17 +79,6 @@ class ContextSlotCache {
 
     VariableMode mode() { return ModeField::decode(value_); }
 
-    VariableLocation location() {
-      switch (VariableLocationField::decode(value_)) {
-        case kContext:
-          return VariableLocation::CONTEXT;
-        case kGlobal:
-          return VariableLocation::GLOBAL;
-      }
-      UNREACHABLE();
-      return VariableLocation::CONTEXT;
-    }
-
     InitializationFlag initialization_flag() {
       return InitField::decode(value_);
     }
@@ -116,9 +94,7 @@ class ContextSlotCache {
     class ModeField : public BitField<VariableMode, 0, 4> {};
     class InitField : public BitField<InitializationFlag, 4, 1> {};
     class MaybeAssignedField : public BitField<MaybeAssignedFlag, 5, 1> {};
-    class VariableLocationField : public BitField<VariableLocationFlag, 6, 1> {
-    };
-    class IndexField : public BitField<int, 7, 32 - 7> {};
+    class IndexField : public BitField<int, 6, 32 - 6> {};
 
    private:
     uint32_t value_;