Speed up access to global variables from eval scopes. Traverse the...

src/scopes.cc

 // Copyright 2006-2008 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 286 matching lines @@
 }
 
 
 // Make sure the method gets instantiated by the template system.
 template void Scope::CollectUsedVariables(
     List<Variable*, FreeStoreAllocationPolicy>* locals);
 template void Scope::CollectUsedVariables(
     List<Variable*, PreallocatedStorage>* locals);
 
 
-void Scope::AllocateVariables() {
+void Scope::AllocateVariables(Handle<Context> context) {
   ASSERT(outer_scope_ == NULL);  // eval or global scopes only
 
   // 1) Propagate scope information.
   // If we are in an eval scope, we may have other outer scopes about
   // which we don't know anything at this point. Thus we must be conservative
   // and assume they may invoke eval themselves. Eventually we could capture
   // this information in the ScopeInfo and then use it here (by traversing
   // the call chain stack, at compile time).
   bool eval_scope = is_eval_scope();
   PropagateScopeInfo(eval_scope, eval_scope);
 
   // 2) Resolve variables.
   Scope* global_scope = NULL;
   if (is_global_scope()) global_scope = this;
-  ResolveVariablesRecursively(global_scope);
+  ResolveVariablesRecursively(global_scope, context);
 
   // 3) Allocate variables.
   AllocateVariablesRecursively();
 }
 
 
 bool Scope::AllowsLazyCompilation() const {
   return !force_eager_compilation_ && HasTrivialOuterContext();
 }
 
@@ skipping 237 matching lines @@
   // If the variable we have found is just a guess, invalidate the result.
   if (guess) {
     *invalidated_local = var;
     var = NULL;
   }
 
   return var;
 }
 
 
-void Scope::ResolveVariable(Scope* global_scope, VariableProxy* proxy) {
+void Scope::ResolveVariable(Scope* global_scope,
+                            Handle<Context> context,
+                            VariableProxy* proxy) {
   ASSERT(global_scope == NULL || global_scope->is_global_scope());
 
   // If the proxy is already resolved there's nothing to do
   // (functions and consts may be resolved by the parser).
   if (proxy->var() != NULL) return;
 
   // Otherwise, try to resolve the variable.
   Variable* invalidated_local = NULL;
   Variable* var = LookupRecursive(proxy->name(), false, &invalidated_local);
 
@@ skipping 40 matching lines @@
 
       } else if (invalidated_local != NULL) {
         // No with statements are involved and we found a local
         // variable that might be shadowed by eval introduced
         // variables.
         var = NonLocal(proxy->name(), Variable::DYNAMIC_LOCAL);
         var->set_local_if_not_shadowed(invalidated_local);
 
       } else if (outer_scope_is_eval_scope_) {
         // No with statements and we did not find a local and the code
-        // is executed with a call to eval.  We don't know anything
-        // because we do not have information about the scopes
-        // surrounding the eval call.
-        var = NonLocal(proxy->name(), Variable::DYNAMIC);
+        // is executed with a call to eval.  The context contains
+        // scope information that we can use to determine if the
+        // variable is global if it is not shadowed by eval-introduced
+        // variables.
+        if (context->GlobalIfNotShadowedByEval(proxy->name())) {
+          var = NonLocal(proxy->name(), Variable::DYNAMIC_GLOBAL);
+
+        } else {
+          var = NonLocal(proxy->name(), Variable::DYNAMIC);
+        }
 
       } else {
         // No with statements and we did not find a local and the code
         // is not executed with a call to eval.  We know that this
         // variable is global unless it is shadowed by eval-introduced
         // variables.
         var = NonLocal(proxy->name(), Variable::DYNAMIC_GLOBAL);
       }
     }
   }
 
   proxy->BindTo(var);
 }
 
 
-void Scope::ResolveVariablesRecursively(Scope* global_scope) {
+void Scope::ResolveVariablesRecursively(Scope* global_scope,
+                                        Handle<Context> context) {
   ASSERT(global_scope == NULL || global_scope->is_global_scope());
 
   // Resolve unresolved variables for this scope.
   for (int i = 0; i < unresolved_.length(); i++) {
-    ResolveVariable(global_scope, unresolved_[i]);
+    ResolveVariable(global_scope, context, unresolved_[i]);
   }
 
   // Resolve unresolved variables for inner scopes.
   for (int i = 0; i < inner_scopes_.length(); i++) {
-    inner_scopes_[i]->ResolveVariablesRecursively(global_scope);
+    inner_scopes_[i]->ResolveVariablesRecursively(global_scope, context);
   }
 }
 
 
 bool Scope::PropagateScopeInfo(bool outer_scope_calls_eval,
                                bool outer_scope_is_eval_scope) {
   if (outer_scope_calls_eval) {
     outer_scope_calls_eval_ = true;
   }
 
@@ skipping 246 matching lines @@
   if (num_heap_slots_ == Context::MIN_CONTEXT_SLOTS &&
       !must_have_local_context) {
     num_heap_slots_ = 0;
   }
 
   // Allocation done.
   ASSERT(num_heap_slots_ == 0 || num_heap_slots_ >= Context::MIN_CONTEXT_SLOTS);
 }
 
 } }  // namespace v8::internal