Link function contexts directly to the previous context.

src/contexts.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 169 matching lines @@
             PrintF("=> found intermediate function in context slot %d\n",
                    index);
           }
           *index_ = index;
           *attributes = READ_ONLY;
           return context;
         }
       }
     }
 
-    // proceed with enclosing context
+    // Proceed with the previous context.
     if (context->IsGlobalContext()) {
       follow_context_chain = false;
-    } else if (context->IsFunctionContext()) {
-      context = Handle<Context>(context->closure()->context(), isolate);
     } else {
       context = Handle<Context>(context->previous(), isolate);
     }
   } while (follow_context_chain);
 
   // slot not found
   if (FLAG_trace_contexts) {
     PrintF("=> no property/slot found\n");
   }
   return Handle<Object>::null();
@@ skipping 22 matching lines @@
     ASSERT(index < 0 || index >= MIN_CONTEXT_SLOTS);
     if (index >= 0) return false;
 
     // Check parameter locals.
     int param_index = scope_info->ParameterIndex(*name);
     if (param_index >= 0) return false;
 
     // Check context only holding the function name variable.
     index = scope_info->FunctionContextSlotIndex(*name);
     if (index >= 0) return false;
-    context = Context::cast(context->closure()->context());
+    context = context->previous();
   }
 
   // No local or potential with statement found so the variable is
   // global unless it is shadowed by an eval-introduced variable.
   return true;
 }
 
 
 void Context::ComputeEvalScopeInfo(bool* outer_scope_calls_eval,
                                    bool* outer_scope_calls_non_strict_eval) {
-  Context* context = this;
-  while (true) {
+  // Skip up the context chain checking all the function contexts to see
+  // whether they call eval.
+  Context* context = fcontext();
+  while (!context->IsGlobalContext()) {
     Handle<SerializedScopeInfo> scope_info(
         context->closure()->shared()->scope_info());
     if (scope_info->CallsEval()) {
       *outer_scope_calls_eval = true;
       if (!scope_info->IsStrictMode()) {
         // No need to go further since the answers will not change
         // from here.
         *outer_scope_calls_non_strict_eval = true;
         return;
       }
     }
-    if (context->IsGlobalContext()) break;
-    context = Context::cast(context->closure()->context());
+    context = context->previous()->fcontext();
   }
 }
 
 
 void Context::AddOptimizedFunction(JSFunction* function) {
   ASSERT(IsGlobalContext());
 #ifdef DEBUG
   Object* element = get(OPTIMIZED_FUNCTIONS_LIST);
   while (!element->IsUndefined()) {
     CHECK(element != function);
@@ skipping 66 matching lines @@
   // During bootstrapping we allow all objects to pass as global
   // objects. This is necessary to fix circular dependencies.
   Isolate* isolate = Isolate::Current();
   return isolate->heap()->gc_state() != Heap::NOT_IN_GC ||
       isolate->bootstrapper()->IsActive() ||
       object->IsGlobalObject();
 }
 #endif
 
 } }  // namespace v8::internal