Static resolution of outer variables in eval code.

src/parser.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 717 matching lines @@
 
   mode_ = PARSE_EAGERLY;
 
   // Place holder for the result.
   FunctionLiteral* result = NULL;
 
   {
     // Parse the function literal.
     Scope* scope = NewScope(top_scope_, GLOBAL_SCOPE);
     if (!info->closure().is_null()) {
-      scope = Scope::DeserializeScopeChain(info, scope);
+      scope = Scope::DeserializeScopeChain(info->closure()->context(), scope);
     }
     FunctionState function_state(this, scope, isolate());
     ASSERT(scope->strict_mode_flag() == kNonStrictMode ||
            scope->strict_mode_flag() == info->strict_mode_flag());
     ASSERT(info->strict_mode_flag() == shared_info->strict_mode_flag());
     scope->SetStrictModeFlag(shared_info->strict_mode_flag());
     FunctionLiteral::Type type = shared_info->is_expression()
         ? (shared_info->is_anonymous()
               ? FunctionLiteral::ANONYMOUS_EXPRESSION
               : FunctionLiteral::NAMED_EXPRESSION)
@@ skipping 606 matching lines @@
                                bool resolve,
                                bool* ok) {
   Variable* var = NULL;
   // If we are inside a function, a declaration of a var/const variable is a
   // truly local variable, and the scope of the variable is always the function
   // scope.
   // Let/const variables in harmony mode are always added to the immediately
   // enclosing scope.
   Scope* declaration_scope = (mode == LET || mode == CONST_HARMONY)
       ? top_scope_ : top_scope_->DeclarationScope();
+  InitializationFlag init_flag = (fun != NULL || mode == VAR)
+      ? kCreatedInitialized : kNeedsInitialization;
 
   // If a function scope exists, then we can statically declare this
   // variable and also set its mode. In any case, a Declaration node
   // will be added to the scope so that the declaration can be added
   // to the corresponding activation frame at runtime if necessary.
   // For instance declarations inside an eval scope need to be added
   // to the calling function context.
   // Similarly, strict mode eval scope does not leak variable declarations to
   // the caller's scope so we declare all locals, too.
   // Also for block scoped let/const bindings the variable can be
   // statically declared.
   if (declaration_scope->is_function_scope() ||
       declaration_scope->is_strict_mode_eval_scope() ||
       declaration_scope->is_block_scope()) {
     // Declare the variable in the function scope.
     var = declaration_scope->LocalLookup(name);
     if (var == NULL) {
       // Declare the name.
-      InitializationFlag init_flag = (fun != NULL || mode == VAR)
-          ? kCreatedInitialized : kNeedsInitialization;
       var = declaration_scope->DeclareLocal(name, mode, init_flag);
     } else {
       // The name was declared in this scope before; check for conflicting
       // re-declarations. We have a conflict if either of the declarations is
       // not a var. There is similar code in runtime.cc in the Declare
       // functions. The function CheckNonConflictingScope checks for conflicting
       // var and let bindings from different scopes whereas this is a check for
       // conflicting declarations within the same scope. This check also covers
       //
       // function () { let x; { var x; } }
@@ skipping 42 matching lines @@
   // WARNING: This will lead to multiple declaration nodes for the
   // same variable if it is declared several times. This is not a
   // semantic issue as long as we keep the source order, but it may be
   // a performance issue since it may lead to repeated
   // Runtime::DeclareContextSlot() calls.
   VariableProxy* proxy = declaration_scope->NewUnresolved(
       name, scanner().location().beg_pos);
   declaration_scope->AddDeclaration(
       new(zone()) Declaration(proxy, mode, fun, top_scope_));
 
-  // For global const variables we bind the proxy to a variable.
   if ((mode == CONST || mode == CONST_HARMONY) &&
       declaration_scope->is_global_scope()) {
+    // For global const variables we bind the proxy to a variable.
     ASSERT(resolve);  // should be set by all callers
     Variable::Kind kind = Variable::NORMAL;
     var = new(zone()) Variable(declaration_scope,
                                name,
-                               CONST,
+                               mode,
                                true,
                                kind,
                                kNeedsInitialization);
+  } else if (declaration_scope->is_eval_scope() &&
+             !declaration_scope->is_strict_mode()) {
+    // For variable declarations in a non-strict eval scope the proxy is bound
+    // to a lookup variable to force a dynamic declaration using the
+    // DeclareContextSlot runtime function.
+    Variable::Kind kind = Variable::NORMAL;
+    var = new(zone()) Variable(declaration_scope,
+                               name,
+                               mode,
+                               true,
+                               kind,
+                               init_flag);
+    var->AllocateTo(Variable::LOOKUP, -1);
+    resolve = true;
   }
 
   // If requested and we have a local variable, bind the proxy to the variable
   // at parse-time. This is used for functions (and consts) declared inside
   // statements: the corresponding function (or const) variable must be in the
   // function scope and not a statement-local scope, e.g. as provided with a
   // 'with' statement:
   //
   //   with (obj) {
   //     function f() {}
@@ skipping 426 matching lines @@
         // the number of arguments (2 or 3).
         initialize =
             new(zone()) CallRuntime(
                 isolate(),
                 isolate()->factory()->InitializeVarGlobal_symbol(),
                 Runtime::FunctionForId(Runtime::kInitializeVarGlobal),
                 arguments);
       }
 
       block->AddStatement(new(zone()) ExpressionStatement(initialize));
+    } else if (needs_init) {
+      // Constant initializations always assign to the declared constant which
+      // is always at the function scope level. This is only relevant for
+      // dynamically looked-up variables and constants (the start context for
+      // constant lookups is always the function context, while it is the top
+      // context for var declared variables). Sigh...
+      // For 'let' and 'const' declared variables in harmony mode the
+      // initialization also always assigns to the declared variable.
+      ASSERT(proxy != NULL);
+      ASSERT(proxy->var() != NULL);
+      ASSERT(value != NULL);
+      Assignment* assignment =
+          new(zone()) Assignment(isolate(), init_op, proxy, value, position);
+      block->AddStatement(new(zone()) ExpressionStatement(assignment));
+      value = NULL;
     }
 
     // Add an assignment node to the initialization statement block if we still
-    // have a pending initialization value. We must distinguish between
-    // different kinds of declarations: 'var' initializations are simply
-    // assignments (with all the consequences if they are inside a 'with'
-    // statement - they may change a 'with' object property). Constant
-    // initializations always assign to the declared constant which is
-    // always at the function scope level. This is only relevant for
-    // dynamically looked-up variables and constants (the start context
-    // for constant lookups is always the function context, while it is
-    // the top context for var declared variables). Sigh...
-    // For 'let' and 'const' declared variables in harmony mode the
-    // initialization is in the same scope as the declaration. Thus dynamic
-    // lookups are unnecessary even if the block scope is inside a with.
+    // have a pending initialization value.
     if (value != NULL) {
+      ASSERT(mode == VAR);
+      // 'var' initializations are simply assignments (with all the consequences
+      // if they are inside a 'with' statement - they may change a 'with' object
+      // property).
       VariableProxy* proxy = initialization_scope->NewUnresolved(name);
       Assignment* assignment =
           new(zone()) Assignment(isolate(), init_op, proxy, value, position);
       block->AddStatement(new(zone()) ExpressionStatement(assignment));
     }
 
     if (fni_ != NULL) fni_->Leave();
   } while (peek() == Token::COMMA);
 
   // If there was a single non-const declaration, return it in the output
@@ skipping 3488 matching lines @@
       result = parser.ParseProgram(source,
                                    info->is_global(),
                                    info->strict_mode_flag());
     }
   }
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal