[strong] Implement static restrictions on binding/assignment to 'undefined' identifier.

src/preparser.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 35 matching lines @@
     return PreParserIdentifier::Static();
   } else if (scanner->current_token() == Token::YIELD) {
     return PreParserIdentifier::Yield();
   }
   if (scanner->UnescapedLiteralMatches("eval", 4)) {
     return PreParserIdentifier::Eval();
   }
   if (scanner->UnescapedLiteralMatches("arguments", 9)) {
     return PreParserIdentifier::Arguments();
   }
+  if (scanner->UnescapedLiteralMatches("undefined", 9)) {
+    return PreParserIdentifier::Undefined();
+  }
   if (scanner->LiteralMatches("prototype", 9)) {
     return PreParserIdentifier::Prototype();
   }
   if (scanner->LiteralMatches("constructor", 11)) {
     return PreParserIdentifier::Constructor();
   }
   return PreParserIdentifier::Default();
 }
 
 
@@ skipping 410 matching lines @@
 
   // The scope of a var/const declared variable anywhere inside a function
   // is the entire function (ECMA-262, 3rd, 10.1.3, and 12.2). The scope
   // of a let declared variable is the scope of the immediately enclosing
   // block.
   int nvars = 0;  // the number of variables declared
   int bindings_start = peek_position();
   do {
     // Parse variable name.
     if (nvars > 0) Consume(Token::COMMA);
-    ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     Scanner::Location variable_loc = scanner()->location();
     nvars++;
     if (peek() == Token::ASSIGN || require_initializer ||
         // require initializers for multiple consts.
         (is_strict_const && peek() == Token::COMMA)) {
       Expect(Token::ASSIGN, CHECK_OK);
       ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
 
       variable_loc.end_pos = scanner()->location().end_pos;
       if (first_initializer_loc && !first_initializer_loc->IsValid()) {
@@ skipping 84 matching lines @@
   // ContinueStatement ::
   //   'continue' [no line terminator] Identifier? ';'
 
   Expect(Token::CONTINUE, CHECK_OK);
   Token::Value tok = peek();
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON &&
       tok != Token::RBRACE &&
       tok != Token::EOS) {
     // ECMA allows "eval" or "arguments" as labels even in strict mode.
-    ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+    ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   }
   ExpectSemicolon(CHECK_OK);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseBreakStatement(bool* ok) {
   // BreakStatement ::
   //   'break' [no line terminator] Identifier? ';'
 
   Expect(Token::BREAK, CHECK_OK);
   Token::Value tok = peek();
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       tok != Token::SEMICOLON &&
       tok != Token::RBRACE &&
       tok != Token::EOS) {
     // ECMA allows "eval" or "arguments" as labels even in strict mode.
-    ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+    ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   }
   ExpectSemicolon(CHECK_OK);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseReturnStatement(bool* ok) {
   // ReturnStatement ::
   //   'return' [no line terminator] Expression? ';'
 
@@ skipping 226 matching lines @@
 
   Token::Value tok = peek();
   if (tok != Token::CATCH && tok != Token::FINALLY) {
     ReportMessageAt(scanner()->location(), "no_catch_or_finally");
     *ok = false;
     return Statement::Default();
   }
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
     Expect(Token::LPAREN, CHECK_OK);
-    ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK);
     Expect(Token::RPAREN, CHECK_OK);
     {
       Scope* with_scope = NewScope(scope_, WITH_SCOPE);
       BlockState block_state(&scope_, with_scope);
       ParseBlock(CHECK_OK);
     }
     tok = peek();
   }
   if (tok == Token::FINALLY) {
     Consume(Token::FINALLY);
@@ skipping 43 matching lines @@
   Expect(Token::LPAREN, CHECK_OK);
   int start_position = position();
   DuplicateFinder duplicate_finder(scanner()->unicode_cache());
   // We don't yet know if the function will be strict, so we cannot yet produce
   // errors for parameter names or duplicates. However, we remember the
   // locations of these errors if they occur and produce the errors later.
   Scanner::Location eval_args_error_loc = Scanner::Location::invalid();
   Scanner::Location dupe_error_loc = Scanner::Location::invalid();
   Scanner::Location reserved_error_loc = Scanner::Location::invalid();
 
+  // Similarly for strong mode.
+  Scanner::Location undefined_error_loc = Scanner::Location::invalid();
+
   bool is_rest = false;
   bool done = arity_restriction == FunctionLiteral::GETTER_ARITY ||
       (peek() == Token::RPAREN &&
        arity_restriction != FunctionLiteral::SETTER_ARITY);
   while (!done) {
     bool is_strict_reserved = false;
     is_rest = peek() == Token::ELLIPSIS && allow_harmony_rest_params();
     if (is_rest) {
       Consume(Token::ELLIPSIS);
     }
 
     Identifier param_name =
         ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
     if (!eval_args_error_loc.IsValid() && param_name.IsEvalOrArguments()) {
       eval_args_error_loc = scanner()->location();
     }
+    if (!undefined_error_loc.IsValid() && param_name.IsUndefined()) {
+      undefined_error_loc = scanner()->location();
+    }
     if (!reserved_error_loc.IsValid() && is_strict_reserved) {
       reserved_error_loc = scanner()->location();
     }
 
     int prev_value = scanner()->FindSymbol(&duplicate_finder, 1);
 
     if (!dupe_error_loc.IsValid() && prev_value != 0) {
       dupe_error_loc = scanner()->location();
     }
 
@@ skipping 23 matching lines @@
     ParseStatementList(Token::RBRACE, CHECK_OK);
   }
   Expect(Token::RBRACE, CHECK_OK);
 
   // Validate name and parameter names. We can do this only after parsing the
   // function, since the function can declare itself strict.
   CheckFunctionName(language_mode(), kind, function_name,
                     name_is_strict_reserved, function_name_location, CHECK_OK);
   const bool use_strict_params = is_rest || IsConciseMethod(kind);
   CheckFunctionParameterNames(language_mode(), use_strict_params,
-                              eval_args_error_loc, dupe_error_loc,
-                              reserved_error_loc, CHECK_OK);
+                              eval_args_error_loc, undefined_error_loc,
+                              dupe_error_loc, reserved_error_loc, CHECK_OK);
 
   if (is_strict(language_mode())) {
     int end_position = scanner()->location().end_pos;
     CheckStrictOctalLiteral(start_position, end_position, CHECK_OK);
   }
 
   if (is_strong(language_mode()) && IsSubclassConstructor(kind)) {
     if (!function_state.super_call_location().IsValid()) {
       ReportMessageAt(function_name_location, "strong_super_call_missing",
                       kReferenceError);
@@ skipping 28 matching lines @@
   if (name_is_strict_reserved) {
     ReportMessageAt(class_name_location, "unexpected_strict_reserved");
     *ok = false;
     return EmptyExpression();
   }
   if (IsEvalOrArguments(name)) {
     ReportMessageAt(class_name_location, "strict_eval_arguments");
     *ok = false;
     return EmptyExpression();
   }
+  LanguageMode class_language_mode = language_mode();
+  if (is_strong(class_language_mode) && IsUndefined(name)) {
+    ReportMessageAt(class_name_location, "strong_undefined");
+    *ok = false;
+    return EmptyExpression();
+  }
 
   Scope* scope = NewScope(scope_, BLOCK_SCOPE);
   BlockState block_state(&scope_, scope);
   scope_->SetLanguageMode(
-      static_cast<LanguageMode>(scope_->language_mode() | STRICT_BIT));
+      static_cast<LanguageMode>(class_language_mode | STRICT_BIT));
   // TODO(marja): Make PreParser use scope names too.
   // scope_->SetScopeName(name);
 
   bool has_extends = Check(Token::EXTENDS);
   if (has_extends) {
     ParseLeftHandSideExpression(CHECK_OK);
   }
 
   ClassLiteralChecker checker(this);
   bool has_seen_constructor = false;
@@ skipping 17 matching lines @@
 
 PreParser::Expression PreParser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
   Expect(Token::MOD, CHECK_OK);
   if (!allow_natives()) {
     *ok = false;
     return Expression::Default();
   }
   // Allow "eval" or "arguments" for backward compatibility.
-  ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+  ParseIdentifier(kAllowRestrictedIdentifiers, CHECK_OK);
   Scanner::Location spread_pos;
   ParseArguments(&spread_pos, ok);
 
   DCHECK(!spread_pos.IsValid());
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal