Make strict more error messages about "eval" and "arguments" less specific.

src/parser.cc

 // Copyright 2012 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 965 matching lines @@
     }
   }
 }
 
 
 Statement* Parser::ParseModuleDeclaration(ZoneStringList* names, bool* ok) {
   // ModuleDeclaration:
   //    'module' Identifier Module
 
   int pos = peek_position();
-  Handle<String> name = ParseIdentifier(CHECK_OK);
+  Handle<String> name = ParseIdentifier(false, CHECK_OK);

[ulan, 2014/02/05 16:05:42]

I prefer enums to flags, because they are more readable, like:
ParseIdentifier(STRICT_EVAL_ARGUMENTS, CHECK_OK);
ParseIdentifier(CLASSIC_EVAL_ARGUMENTS, CHECK_OK);
but you may disagree.

[marja, 2014/02/05 16:18:02]

Done: kDontAllowEnumOrArguments and kAllowEnumOrArguments. (This is independent
of the strict vs. classic mode; even in strict mode we allow them in some
contexts ("var foo = eval;"))

 
 #ifdef DEBUG
   if (FLAG_print_interface_details)
     PrintF("# Module %s...\n", name->ToAsciiArray());
 #endif
 
   Module* module = ParseModule(CHECK_OK);
   VariableProxy* proxy = NewUnresolved(name, MODULE, module->interface());
   Declaration* declaration =
       factory()->NewModuleDeclaration(proxy, module, top_scope_, pos);
@@ skipping 132 matching lines @@
 
   return result;
 }
 
 
 Module* Parser::ParseModuleVariable(bool* ok) {
   // ModulePath:
   //    Identifier
 
   int pos = peek_position();
-  Handle<String> name = ParseIdentifier(CHECK_OK);
+  Handle<String> name = ParseIdentifier(false, CHECK_OK);
 #ifdef DEBUG
   if (FLAG_print_interface_details)
     PrintF("# Module variable %s ", name->ToAsciiArray());
 #endif
   VariableProxy* proxy = top_scope_->NewUnresolved(
       factory(), name, Interface::NewModule(zone()),
       scanner().location().beg_pos);
 
   return factory()->NewModuleVariable(proxy, pos);
 }
@@ skipping 104 matching lines @@
   //
   // TODO(ES6): implement structuring ExportSpecifiers
 
   Expect(Token::EXPORT, CHECK_OK);
 
   Statement* result = NULL;
   ZoneStringList names(1, zone());
   switch (peek()) {
     case Token::IDENTIFIER: {
       int pos = position();
-      Handle<String> name = ParseIdentifier(CHECK_OK);
+      Handle<String> name = ParseIdentifier(false, CHECK_OK);
       // Handle 'module' as a context-sensitive keyword.
       if (!name->IsOneByteEqualTo(STATIC_ASCII_VECTOR("module"))) {
         names.Add(name, zone());
         while (peek() == Token::COMMA) {
           Consume(Token::COMMA);
-          name = ParseIdentifier(CHECK_OK);
+          name = ParseIdentifier(false, CHECK_OK);
           names.Add(name, zone());
         }
         ExpectSemicolon(CHECK_OK);
         result = factory()->NewEmptyStatement(pos);
       } else {
         result = ParseModuleDeclaration(&names, CHECK_OK);
       }
       break;
     }
 
@@ skipping 344 matching lines @@
 }
 
 
 // Language extension which is only enabled for source files loaded
 // through the API's extension mechanism.  A native function
 // declaration is resolved by looking up the function through a
 // callback provided by the extension.
 Statement* Parser::ParseNativeDeclaration(bool* ok) {
   int pos = peek_position();
   Expect(Token::FUNCTION, CHECK_OK);
-  Handle<String> name = ParseIdentifier(CHECK_OK);
+  // Allow "eval" or "arguments" for backward compatibility.
+  Handle<String> name = ParseIdentifier(true, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   bool done = (peek() == Token::RPAREN);
   while (!done) {
-    ParseIdentifier(CHECK_OK);
+    ParseIdentifier(true, CHECK_OK);
     done = (peek() == Token::RPAREN);
     if (!done) {
       Expect(Token::COMMA, CHECK_OK);
     }
   }
   Expect(Token::RPAREN, CHECK_OK);
   Expect(Token::SEMICOLON, CHECK_OK);
 
   // Make sure that the function containing the native declaration
   // isn't lazily compiled. The extension structures are only
@@ skipping 243 matching lines @@
   //
   // Create new block with one expected declaration.
   Block* block = factory()->NewBlock(NULL, 1, true, pos);
   int nvars = 0;  // the number of variables declared
   Handle<String> name;
   do {
     if (fni_ != NULL) fni_->Enter();
 
     // Parse variable name.
     if (nvars > 0) Consume(Token::COMMA);
-    name = ParseIdentifier(CHECK_OK);
+    name = ParseIdentifier(false, CHECK_OK);
     if (fni_ != NULL) fni_->PushVariableName(name);
 
-    // Strict mode variables may not be named eval or arguments
-    if (!declaration_scope->is_classic_mode() && IsEvalOrArguments(name)) {
-      ReportMessage("strict_var_name", Vector<const char*>::empty());
-      *ok = false;
-      return NULL;
-    }
-
     // Declare variable.
     // Note that we *always* must treat the initial value via a separate init
     // assignment for variables and constants because the value must be assigned
     // when the variable is encountered in the source. But the variable/constant
     // is declared (and set to 'undefined') upon entering the function within
     // which the variable or constant is declared. Only function variables have
     // an initial value in the declaration (because they are initialized upon
     // entering the function).
     //
     // If we have a const declaration, in an inner scope, the proxy is always
@@ skipping 294 matching lines @@
 Statement* Parser::ParseContinueStatement(bool* ok) {
   // ContinueStatement ::
   //   'continue' Identifier? ';'
 
   int pos = peek_position();
   Expect(Token::CONTINUE, CHECK_OK);
   Handle<String> label = Handle<String>::null();
   Token::Value tok = peek();
   if (!scanner().HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON && tok != Token::RBRACE && tok != Token::EOS) {
-    label = ParseIdentifier(CHECK_OK);
+    // ECMA allows "eval" or "arguments" as labels even in strict mode.
+    label = ParseIdentifier(true, CHECK_OK);
   }
   IterationStatement* target = NULL;
   target = LookupContinueTarget(label, CHECK_OK);
   if (target == NULL) {
     // Illegal continue statement.
     const char* message = "illegal_continue";
     Vector<Handle<String> > args;
     if (!label.is_null()) {
       message = "unknown_label";
       args = Vector<Handle<String> >(&label, 1);
@@ skipping 10 matching lines @@
 Statement* Parser::ParseBreakStatement(ZoneStringList* labels, bool* ok) {
   // BreakStatement ::
   //   'break' Identifier? ';'
 
   int pos = peek_position();
   Expect(Token::BREAK, CHECK_OK);
   Handle<String> label;
   Token::Value tok = peek();
   if (!scanner().HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON && tok != Token::RBRACE && tok != Token::EOS) {
-    label = ParseIdentifier(CHECK_OK);
+    // ECMA allows "eval" or "arguments" as labels even in strict mode.
+    label = ParseIdentifier(true, CHECK_OK);
   }
   // Parse labeled break statements that target themselves into
   // empty statements, e.g. 'l1: l2: l3: break l2;'
   if (!label.is_null() && ContainsLabel(labels, label)) {
     ExpectSemicolon(CHECK_OK);
     return factory()->NewEmptyStatement(pos);
   }
   BreakableStatement* target = NULL;
   target = LookupBreakTarget(label, CHECK_OK);
   if (target == NULL) {
@@ skipping 209 matching lines @@
   Scope* catch_scope = NULL;
   Variable* catch_variable = NULL;
   Block* catch_block = NULL;
   Handle<String> name;
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
 
     Expect(Token::LPAREN, CHECK_OK);
     catch_scope = NewScope(top_scope_, CATCH_SCOPE);
     catch_scope->set_start_position(scanner().location().beg_pos);
-    name = ParseIdentifier(CHECK_OK);
-
-    if (!top_scope_->is_classic_mode() && IsEvalOrArguments(name)) {
-      ReportMessage("strict_catch_variable", Vector<const char*>::empty());
-      *ok = false;
-      return NULL;
-    }
+    name = ParseIdentifier(false, CHECK_OK);
 
     Expect(Token::RPAREN, CHECK_OK);
 
     if (peek() == Token::LBRACE) {
       Target target(&this->target_stack_, &catch_collector);
       VariableMode mode = is_extended_mode() ? LET : VAR;
       catch_variable =
           catch_scope->DeclareLocal(name, mode, kCreatedInitialized);
 
       BlockState block_state(this, catch_scope);
@@ skipping 427 matching lines @@
   // runtime.
   // TODO(ES5): Should change parsing for spec conformance.
   if (expression == NULL || !expression->IsValidLeftHandSide()) {
     Handle<String> message =
         isolate()->factory()->invalid_lhs_in_assignment_string();
     expression = NewThrowReferenceError(message);
   }
 
   if (!top_scope_->is_classic_mode()) {
     // Assignment to eval or arguments is disallowed in strict mode.
-    CheckStrictModeLValue(expression, "strict_lhs_assignment", CHECK_OK);
+    CheckStrictModeLValue(expression, CHECK_OK);
   }
   MarkAsLValue(expression);
 
   Token::Value op = Next();  // Get assignment operator.
   int pos = position();
   Expression* right = ParseAssignmentExpression(accept_IN, CHECK_OK);
 
   // TODO(1231235): We try to estimate the set of properties set by
   // constructors. We define a new property whenever there is an
   // assignment to a property of 'this'. We should probably only add
@@ skipping 259 matching lines @@
     // error here but for compatibility with JSC we choose to report the
     // error at runtime.
     if (expression == NULL || !expression->IsValidLeftHandSide()) {
       Handle<String> message =
           isolate()->factory()->invalid_lhs_in_prefix_op_string();
       expression = NewThrowReferenceError(message);
     }
 
     if (!top_scope_->is_classic_mode()) {
       // Prefix expression operand in strict mode may not be eval or arguments.
-      CheckStrictModeLValue(expression, "strict_lhs_prefix", CHECK_OK);
+      CheckStrictModeLValue(expression, CHECK_OK);
     }
     MarkAsLValue(expression);
 
     return factory()->NewCountOperation(op,
                                         true /* prefix */,
                                         expression,
                                         position());
 
   } else {
     return ParsePostfixExpression(ok);
@@ skipping 13 matching lines @@
     // error here but for compatibility with JSC we choose to report the
     // error at runtime.
     if (expression == NULL || !expression->IsValidLeftHandSide()) {
       Handle<String> message =
           isolate()->factory()->invalid_lhs_in_postfix_op_string();
       expression = NewThrowReferenceError(message);
     }
 
     if (!top_scope_->is_classic_mode()) {
       // Postfix expression operand in strict mode may not be eval or arguments.
-      CheckStrictModeLValue(expression, "strict_lhs_postfix", CHECK_OK);
+      CheckStrictModeLValue(expression, CHECK_OK);
     }
     MarkAsLValue(expression);
 
     Token::Value next = Next();
     expression =
         factory()->NewCountOperation(next,
                                      false /* postfix */,
                                      expression,
                                      position());
   }
@@ skipping 289 matching lines @@
       break;
 
     case Token::FALSE_LITERAL:
       Consume(Token::FALSE_LITERAL);
       result = factory()->NewLiteral(isolate()->factory()->false_value(), pos);
       break;
 
     case Token::IDENTIFIER:
     case Token::YIELD:
     case Token::FUTURE_STRICT_RESERVED_WORD: {
-      Handle<String> name = ParseIdentifier(CHECK_OK);
+      // Using eval or arguments in this context is OK even in strict mode.
+      Handle<String> name = ParseIdentifier(true, CHECK_OK);
       if (fni_ != NULL) fni_->PushVariableName(name);
       // The name may refer to a module instance object, so its type is unknown.
 #ifdef DEBUG
       if (FLAG_print_interface_details)
         PrintF("# Variable %s ", name->ToAsciiArray());
 #endif
       Interface* interface = Interface::NewUnknown(zone());
       result = top_scope_->NewUnresolved(factory(), name, interface, pos);
       break;
     }
@@ skipping 719 matching lines @@
       handler_count = function_state.handler_count();
 
       Expect(Token::RBRACE, CHECK_OK);
       scope->set_end_position(scanner().location().end_pos);
     }
 
     // Validate strict mode.
     if (!top_scope_->is_classic_mode()) {
       if (IsEvalOrArguments(function_name)) {
         ReportMessageAt(function_name_location,
-                        "strict_function_name",
+                        "strict_eval_arguments",
                         Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
       if (name_loc.IsValid()) {
-        ReportMessageAt(name_loc, "strict_param_name",
+        ReportMessageAt(name_loc, "strict_eval_arguments",
                         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;
       }
@@ skipping 68 matching lines @@
   return result;
 }
 
 
 Expression* Parser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
 
   int pos = peek_position();
   Expect(Token::MOD, CHECK_OK);
-  Handle<String> name = ParseIdentifier(CHECK_OK);
+  // Allow "eval" or "arguments" for backward compatibility.
+  Handle<String> name = ParseIdentifier(true, CHECK_OK);
   ZoneList<Expression*>* args = ParseArguments(CHECK_OK);
 
   if (extension_ != NULL) {
     // The extension structures are only accessible while parsing the
     // very first time not when reparsing because of lazy compilation.
     top_scope_->DeclarationScope()->ForceEagerCompilation();
   }
 
   const Runtime::Function* function = Runtime::FunctionForName(name);
 
@@ skipping 86 matching lines @@
 }
 
 
 Literal* Parser::GetLiteralTheHole(int position) {
   return factory()->NewLiteral(
       isolate()->factory()->the_hole_value(), RelocInfo::kNoPosition);
 }
 
 
 // Parses an identifier that is valid for the current scope, in particular it
-// fails on strict mode future reserved keywords in a strict scope.
-Handle<String> Parser::ParseIdentifier(bool* ok) {
+// fails on strict mode future reserved keywords in a strict scope. If
+// allow_eval_arguments is true, we allow "eval" or "arguments" as identifier
+// even in strict mode (this is needed in cases like "var foo = eval;").
+Handle<String> Parser::ParseIdentifier(bool allow_eval_arguments, bool* ok) {
   Token::Value next = Next();
-  if (next == Token::IDENTIFIER ||
-      (top_scope_->is_classic_mode() &&
-       (next == Token::FUTURE_STRICT_RESERVED_WORD ||
-        (next == Token::YIELD && !is_generator())))) {
+  if (next == Token::IDENTIFIER) {
+    Handle<String> name = GetSymbol();
+    if (!allow_eval_arguments && !top_scope_->is_classic_mode() &&
+        IsEvalOrArguments(name)) {
+      ReportMessage("strict_eval_arguments", Vector<const char*>::empty());
+      *ok = false;
+    }
+    return name;
+  } else if (top_scope_->is_classic_mode() &&
+             (next == Token::FUTURE_STRICT_RESERVED_WORD ||
+              (next == Token::YIELD && !is_generator()))) {
     return GetSymbol();
   } else {
     ReportUnexpectedToken(next);
     *ok = false;
     return Handle<String>();
   }
 }
 
 
 // Parses and identifier or a strict mode future reserved word, and indicate
@@ skipping 34 matching lines @@
       ? expression->AsVariableProxy()
       : NULL;
 
   if (proxy != NULL) proxy->MarkAsLValue();
 }
 
 
 // Checks LHS expression for assignment and prefix/postfix increment/decrement
 // in strict mode.
 void Parser::CheckStrictModeLValue(Expression* expression,
-                                   const char* error,
                                    bool* ok) {
   ASSERT(!top_scope_->is_classic_mode());
   VariableProxy* lhs = expression != NULL
       ? expression->AsVariableProxy()
       : NULL;
 
   if (lhs != NULL && !lhs->is_this() && IsEvalOrArguments(lhs->name())) {
-    ReportMessage(error, Vector<const char*>::empty());
+    ReportMessage("strict_eval_arguments", Vector<const char*>::empty());
     *ok = false;
   }
 }
 
 
 // Checks whether an octal literal was last seen between beg_pos and end_pos.
 // If so, reports an error. Only called for strict mode.
 void ParserBase::CheckOctalLiteral(int beg_pos, int end_pos, bool* ok) {
   Scanner::Location octal = scanner()->octal_position();
   if (octal.IsValid() && beg_pos <= octal.beg_pos && octal.end_pos <= end_pos) {
@@ skipping 1096 matching lines @@
       ASSERT(info()->isolate()->has_pending_exception());
     } else {
       result = ParseProgram();
     }
   }
   info()->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal