Issue 117 - strict mode and future reserved words

src/parser.cc

 // Copyright 2010 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 741 matching lines @@
                                scope);
     TemporaryScope temp_scope(&this->temp_scope_);
 
     if (info->strict_mode()) {
       temp_scope.EnableStrictMode();
     }
 
     FunctionLiteralType type =
         info->is_expression() ? EXPRESSION : DECLARATION;
     bool ok = true;
-    result = ParseFunctionLiteral(name, RelocInfo::kNoPosition, type, &ok);
+    result = ParseFunctionLiteral(name,
+                                  false,    // Strict mode name already checked.
+                                  RelocInfo::kNoPosition, type, &ok);
     // Make sure the results agree.
     ASSERT(ok == (result != NULL));
     // The only errors should be stack overflows.
     ASSERT(ok || stack_overflow_);
   }
 
   // Make sure the target stack is empty.
   ASSERT(target_stack_ == NULL);
 
   // If there was a stack overflow we have to get rid of AST and it is
@@ skipping 668 matching lines @@
   return new ExpressionStatement(
       new Assignment(Token::INIT_VAR, var, lit, RelocInfo::kNoPosition));
 }
 
 
 Statement* Parser::ParseFunctionDeclaration(bool* ok) {
   // FunctionDeclaration ::
   //   'function' Identifier '(' FormalParameterListopt ')' '{' FunctionBody '}'
   Expect(Token::FUNCTION, CHECK_OK);
   int function_token_position = scanner().location().beg_pos;
-  Handle<String> name = ParseIdentifier(CHECK_OK);
+  bool is_reserved = false;
+  Handle<String> name = ParseIdentifierOrReservedWord(&is_reserved, CHECK_OK);
   FunctionLiteral* fun = ParseFunctionLiteral(name,
+                                              is_reserved,
                                               function_token_position,
                                               DECLARATION,
                                               CHECK_OK);
   // Even if we're not at the top-level of the global or a function
   // scope, we treat is as such and introduce the function with it's
   // initial value upon entering the corresponding scope.
   Declare(name, Variable::VAR, fun, true, CHECK_OK);
   return EmptyStatement();
 }
 
@@ skipping 238 matching lines @@
 
   return false;
 }
 
 
 Statement* Parser::ParseExpressionOrLabelledStatement(ZoneStringList* labels,
                                                       bool* ok) {
   // ExpressionStatement | LabelledStatement ::
   //   Expression ';'
   //   Identifier ':' Statement
-  bool starts_with_idenfifier = (peek() == Token::IDENTIFIER);
+  bool starts_with_idenfifier = peek_any_identifier();
   Expression* expr = ParseExpression(true, CHECK_OK);
   if (peek() == Token::COLON && starts_with_idenfifier && expr &&
       expr->AsVariableProxy() != NULL &&
       !expr->AsVariableProxy()->is_this()) {
     // Expression is a single identifier, and not, e.g., a parenthesized
     // identifier.
     VariableProxy* var = expr->AsVariableProxy();
     Handle<String> label = var->name();
     // TODO(1240780): We don't check for redeclaration of labels
     // during preparsing since keeping track of the set of active
@@ skipping 968 matching lines @@
   // MemberExpression ::
   //   (PrimaryExpression | FunctionLiteral)
   //     ('[' Expression ']' | '.' Identifier | Arguments)*
 
   // Parse the initial primary or function expression.
   Expression* result = NULL;
   if (peek() == Token::FUNCTION) {
     Expect(Token::FUNCTION, CHECK_OK);
     int function_token_position = scanner().location().beg_pos;
     Handle<String> name;
-    if (peek() == Token::IDENTIFIER) name = ParseIdentifier(CHECK_OK);
-    result = ParseFunctionLiteral(name, function_token_position,
-                                  NESTED, CHECK_OK);
+    bool is_reserved_name = false;
+    if (peek_any_identifier()) {
+        name = ParseIdentifierOrReservedWord(&is_reserved_name, CHECK_OK);
+    }
+    result = ParseFunctionLiteral(name, is_reserved_name,
+                                  function_token_position, NESTED, CHECK_OK);
   } else {
     result = ParsePrimaryExpression(CHECK_OK);
   }
 
   while (true) {
     switch (peek()) {
       case Token::LBRACK: {
         Consume(Token::LBRACK);
         int pos = scanner().location().beg_pos;
         Expression* index = ParseExpression(true, CHECK_OK);
@@ skipping 48 matching lines @@
       return ReportMessage("unexpected_eos", Vector<const char*>::empty());
     case Token::NUMBER:
       return ReportMessage("unexpected_token_number",
                            Vector<const char*>::empty());
     case Token::STRING:
       return ReportMessage("unexpected_token_string",
                            Vector<const char*>::empty());
     case Token::IDENTIFIER:
       return ReportMessage("unexpected_token_identifier",
                            Vector<const char*>::empty());
+    case Token::FUTURE_RESERVED_WORD:
+      return ReportMessage(temp_scope_->StrictMode() ?
+                               "unexpected_strict_reserved" :
+                               "unexpected_token_identifier",
+                           Vector<const char*>::empty());
     default:
       const char* name = Token::String(token);
       ASSERT(name != NULL);
       ReportMessage("unexpected_token", Vector<const char*>(&name, 1));
   }
 }
 
 
 void Parser::ReportInvalidPreparseData(Handle<String> name, bool* ok) {
   SmartPointer<char> name_string = name->ToCString(DISALLOW_NULLS);
@@ skipping 35 matching lines @@
     case Token::TRUE_LITERAL:
       Consume(Token::TRUE_LITERAL);
       result = new Literal(Factory::true_value());
       break;
 
     case Token::FALSE_LITERAL:
       Consume(Token::FALSE_LITERAL);
       result = new Literal(Factory::false_value());
       break;
 
-    case Token::IDENTIFIER: {
+    case Token::IDENTIFIER:
+    case Token::FUTURE_RESERVED_WORD: {
       Handle<String> name = ParseIdentifier(CHECK_OK);
       if (fni_ != NULL) fni_->PushVariableName(name);
       result = top_scope_->NewUnresolved(name, inside_with());
       break;
     }
 
     case Token::NUMBER: {
       Consume(Token::NUMBER);
       ASSERT(scanner().is_literal_ascii());
       double value = StringToDouble(scanner().literal_ascii_string(),
@@ skipping 386 matching lines @@
 
 
 ObjectLiteral::Property* Parser::ParseObjectLiteralGetSet(bool is_getter,
                                                           bool* ok) {
   // Special handling of getter and setter syntax:
   // { ... , get foo() { ... }, ... , set foo(v) { ... v ... } , ... }
   // We have already read the "get" or "set" keyword.
   Token::Value next = Next();
   bool is_keyword = Token::IsKeyword(next);
   if (next == Token::IDENTIFIER || next == Token::NUMBER ||
+      next == Token::FUTURE_RESERVED_WORD ||
       next == Token::STRING || is_keyword) {
     Handle<String> name;
     if (is_keyword) {
       name = Factory::LookupAsciiSymbol(Token::String(next));
     } else {
       name = GetSymbol(CHECK_OK);
     }
     FunctionLiteral* value =
         ParseFunctionLiteral(name,
+                             false,   // reserved words are allowed here
                              RelocInfo::kNoPosition,
                              DECLARATION,
                              CHECK_OK);
     // Allow any number of parameters for compatiabilty with JSC.
     // Specification only allows zero parameters for get and one for set.
     ObjectLiteral::Property* property =
         new ObjectLiteral::Property(is_getter, value);
     return property;
   } else {
     ReportUnexpectedToken(next);
@@ skipping 22 matching lines @@
   while (peek() != Token::RBRACE) {
     if (fni_ != NULL) fni_->Enter();
 
     Literal* key = NULL;
     Token::Value next = peek();
 
     // Location of the property name token
     Scanner::Location loc = scanner().peek_location();
 
     switch (next) {
+      case Token::FUTURE_RESERVED_WORD:
       case Token::IDENTIFIER: {
         bool is_getter = false;
         bool is_setter = false;
         Handle<String> id =
             ParseIdentifierOrGetOrSet(&is_getter, &is_setter, CHECK_OK);
         if (fni_ != NULL) fni_->PushLiteralName(id);
 
         if ((is_getter || is_setter) && peek() != Token::COLON) {
             // Update loc to point to the identifier
             loc = scanner().peek_location();
@@ skipping 128 matching lines @@
     result->Add(argument);
     done = (peek() == Token::RPAREN);
     if (!done) Expect(Token::COMMA, CHECK_OK);
   }
   Expect(Token::RPAREN, CHECK_OK);
   return result;
 }
 
 
 FunctionLiteral* Parser::ParseFunctionLiteral(Handle<String> var_name,
+                                              bool name_is_reserved,
                                               int function_token_position,
                                               FunctionLiteralType type,
                                               bool* ok) {
   // Function ::
   //   '(' FormalParameterList? ')' '{' FunctionBody '}'
   bool is_named = !var_name.is_null();
 
   // The name associated with this function. If it's a function expression,
   // this is the actual function name, otherwise this is the name of the
   // variable declared and initialized with the function (expression). In
@@ skipping 13 matching lines @@
                                scope);
     TemporaryScope temp_scope(&this->temp_scope_);
     top_scope_->SetScopeName(name);
 
     //  FormalParameterList ::
     //    '(' (Identifier)*[','] ')'
     Expect(Token::LPAREN, CHECK_OK);
     int start_pos = scanner().location().beg_pos;
     Scanner::Location name_loc = Scanner::NoLocation();
     Scanner::Location dupe_loc = Scanner::NoLocation();
+    Scanner::Location reserved_loc = Scanner::NoLocation();
 
     bool done = (peek() == Token::RPAREN);
     while (!done) {
-      Handle<String> param_name = ParseIdentifier(CHECK_OK);
+      bool is_reserved = false;
+      Handle<String> param_name =
+          ParseIdentifierOrReservedWord(&is_reserved, CHECK_OK);
 
       // Store locations for possible future error reports.
       if (!name_loc.IsValid() && IsEvalOrArguments(param_name)) {
         name_loc = scanner().location();
       }
       if (!dupe_loc.IsValid() && top_scope_->IsDeclared(param_name)) {
         dupe_loc = scanner().location();
       }
+      if (!reserved_loc.IsValid() && is_reserved) {
+        reserved_loc = scanner().location();
+      }
 
       Variable* parameter = top_scope_->DeclareLocal(param_name, Variable::VAR);
       top_scope_->AddParameter(parameter);
       num_parameters++;
       done = (peek() == Token::RPAREN);
       if (!done) Expect(Token::COMMA, CHECK_OK);
     }
     Expect(Token::RPAREN, CHECK_OK);
 
     Expect(Token::LBRACE, CHECK_OK);
@@ skipping 60 matching lines @@
       Expect(Token::RBRACE, CHECK_OK);
       end_pos = scanner().location().end_pos;
     }
 
     // Validate strict mode.
     if (temp_scope_->StrictMode()) {
       if (IsEvalOrArguments(name)) {
         int position = function_token_position != RelocInfo::kNoPosition
             ? function_token_position
             : (start_pos > 0 ? start_pos - 1 : start_pos);
-        ReportMessageAt(Scanner::Location(position, start_pos),
+        Scanner::Location location = Scanner::Location(position, start_pos);
+        ReportMessageAt(location,
                         "strict_function_name", Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
       if (name_loc.IsValid()) {
         ReportMessageAt(name_loc, "strict_param_name",
                         Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
       if (dupe_loc.IsValid()) {
         ReportMessageAt(dupe_loc, "strict_param_dupe",
                         Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
+      if (name_is_reserved) {
+        int position = function_token_position != RelocInfo::kNoPosition
+            ? function_token_position
+            : (start_pos > 0 ? start_pos - 1 : start_pos);
+        Scanner::Location location = Scanner::Location(position, start_pos);
+        ReportMessageAt(location, "strict_reserved_word",
+                        Vector<const char*>::empty());
+        *ok = false;
+        return NULL;
+      }
+      if (reserved_loc.IsValid()) {
+        ReportMessageAt(reserved_loc, "strict_reserved_word",
+                        Vector<const char*>::empty());
+        *ok = false;
+        return NULL;
+      }
       CheckOctalLiteral(start_pos, end_pos, CHECK_OK);
     }
 
     FunctionLiteral* function_literal =
         new FunctionLiteral(name,
                             top_scope_,
                             body,
                             materialized_literal_count,
                             expected_property_count,
                             only_simple_this_property_assignments,
@@ skipping 51 matching lines @@
     ReportMessage("illegal_access", Vector<const char*>::empty());
     *ok = false;
     return NULL;
   }
 
   // We have a valid intrinsics call or a call to a builtin.
   return new CallRuntime(name, function, args);
 }
 
 
+bool Parser::peek_any_identifier() {
+  Token::Value next = peek();
+  return next == Token::IDENTIFIER ||
+         next == Token::FUTURE_RESERVED_WORD;
+}
+
+
 void Parser::Consume(Token::Value token) {
   Token::Value next = Next();
   USE(next);
   USE(token);
   ASSERT(next == token);
 }
 
 
 void Parser::Expect(Token::Value token, bool* ok) {
   Token::Value next = Next();
@@ skipping 39 matching lines @@
   return new Literal(Factory::the_hole_value());
 }
 
 
 Literal* Parser::GetLiteralNumber(double value) {
   return NewNumberLiteral(value);
 }
 
 
 Handle<String> Parser::ParseIdentifier(bool* ok) {
-  Expect(Token::IDENTIFIER, ok);
+  bool is_reserved;
+  return ParseIdentifierOrReservedWord(&is_reserved, ok);
+}
+
+
+Handle<String> Parser::ParseIdentifierOrReservedWord(bool* is_reserved,
+                                                     bool* ok) {
+  *is_reserved = false;
+  if (temp_scope_->StrictMode()) {
+    Expect(Token::IDENTIFIER, ok);
+  } else {
+    if (!Check(Token::IDENTIFIER)) {
+      Expect(Token::FUTURE_RESERVED_WORD, ok);
+      *is_reserved = true;
+    }
+  }
   if (!*ok) return Handle<String>();
   return GetSymbol(ok);
 }
 
 
 Handle<String> Parser::ParseIdentifierName(bool* ok) {
   Token::Value next = Next();
-  if (next != Token::IDENTIFIER && !Token::IsKeyword(next)) {
+  if (next != Token::IDENTIFIER &&
+          next != Token::FUTURE_RESERVED_WORD &&
+          !Token::IsKeyword(next)) {
     ReportUnexpectedToken(next);
     *ok = false;
     return Handle<String>();
   }
   return GetSymbol(ok);
 }
 
 
 // Checks LHS expression for assignment and prefix/postfix increment/decrement
 // in strict mode.
@@ skipping 19 matching lines @@
   if (beg_pos <= octal && octal <= end_pos) {
     ReportMessageAt(Scanner::Location(octal, octal + 1), "strict_octal_literal",
                     Vector<const char*>::empty());
     scanner().clear_octal_position();
     *ok = false;
   }
 }
 
 
 // This function reads an identifier and determines whether or not it
-// is 'get' or 'set'.  The reason for not using ParseIdentifier and
-// checking on the output is that this involves heap allocation which
-// we can't do during preparsing.
+// is 'get' or 'set'.
 Handle<String> Parser::ParseIdentifierOrGetOrSet(bool* is_get,
                                                  bool* is_set,
                                                  bool* ok) {
-  Expect(Token::IDENTIFIER, ok);
+  Handle<String> result = ParseIdentifier(ok);
   if (!*ok) return Handle<String>();
   if (scanner().is_literal_ascii() && scanner().literal_length() == 3) {
     const char* token = scanner().literal_ascii_string().start();
     *is_get = strncmp(token, "get", 3) == 0;
     *is_set = !*is_get && strncmp(token, "set", 3) == 0;
   }
-  return GetSymbol(ok);
+  return result;
 }
 
 
 // ----------------------------------------------------------------------------
 // Parser support
 
 
 bool Parser::TargetStackContainsLabel(Handle<String> label) {
   for (Target* t = target_stack_; t != NULL; t = t->previous()) {
     BreakableStatement* stat = t->node()->AsBreakableStatement();
@@ skipping 121 matching lines @@
         case Token::EOS:
           message = "unexpected_eos";
           break;
         case Token::NUMBER:
           message = "unexpected_token_number";
           break;
         case Token::STRING:
           message = "unexpected_token_string";
           break;
         case Token::IDENTIFIER:
+        case Token::FUTURE_RESERVED_WORD:
           message = "unexpected_token_identifier";
           break;
         default:
           message = "unexpected_token";
           name_opt = Token::String(token);
           ASSERT(name_opt != NULL);
           break;
       }
 
       Scanner::Location source_location = scanner_.location();
@@ skipping 1120 matching lines @@
                                    info->is_global(),
                                    info->StrictMode());
     }
   }
 
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal