Group lexical context variables for faster look up.

src/contexts.cc

 // Copyright 2011 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/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/scopeinfo.h"
 
@@ skipping 38 matching lines @@
     if (slot_index >= 0 && result->location == VariableLocation::CONTEXT) {
       result->context_index = i;
       result->slot_index = slot_index;
       return true;
     }
   }
   return false;
 }
 
 
+bool ScriptContextTable::LookupLexical(Handle<ScriptContextTable> table,
+                                       Handle<String> name) {
+  for (int i = 0; i < table->used(); i++) {
+    Handle<Context> context = GetContext(table, i);
+    DCHECK(context->IsScriptContext());
+    Handle<ScopeInfo> scope_info(ScopeInfo::cast(context->extension()));
+    int slot_index = ScopeInfo::LexicalContextSlotIndex(scope_info, name);
+    if (slot_index >= 0) return true;
+  }
+  return false;
+}
+
+
 Context* Context::declaration_context() {
   Context* current = this;
   while (!current->IsFunctionContext() && !current->IsNativeContext() &&
          !current->IsScriptContext()) {
     current = current->previous();
     DCHECK(current->closure() == closure());
   }
   return current;
 }
 
@@ skipping 442 matching lines @@
   // During bootstrapping we allow all objects to pass as global
   // objects. This is necessary to fix circular dependencies.
   return isolate->heap()->gc_state() != Heap::NOT_IN_GC ||
       isolate->bootstrapper()->IsActive() ||
       object->IsGlobalObject();
 }
 #endif
 
 }  // namespace internal
 }  // namespace v8