Group lexical context variables for faster look up.

src/contexts.h

 // 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.
 
 #ifndef V8_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 
@@ skipping 226 matching lines @@
 
   // Lookup a variable `name` in a ScriptContextTable.
   // If it returns true, the variable is found and `result` contains
   // valid information about its location.
   // If it returns false, `result` is untouched.
   MUST_USE_RESULT
   static bool Lookup(Handle<ScriptContextTable> table, Handle<String> name,
                      LookupResult* result);
 
   MUST_USE_RESULT
+  static bool LookupLexical(Handle<ScriptContextTable> table,
+                            Handle<String> name);
+
+  MUST_USE_RESULT
   static Handle<ScriptContextTable> Extend(Handle<ScriptContextTable> table,
                                            Handle<Context> script_context);
 
   static int GetContextOffset(int context_index) {
     return kFirstContextOffset + context_index * kPointerSize;
   }
 
  private:
   static const int kUsedSlot = 0;
   static const int kFirstContextOffset =
@@ skipping 412 matching lines @@
   static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_