Add strong mode.

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 62 matching lines @@
 
 PreParserIdentifier PreParserTraits::GetNumberAsSymbol(Scanner* scanner) {
   return PreParserIdentifier::Default();
 }
 
 
 PreParserExpression PreParserTraits::ExpressionFromString(
     int pos, Scanner* scanner, PreParserFactory* factory) {
   if (scanner->UnescapedLiteralMatches("use strict", 10)) {
     return PreParserExpression::UseStrictStringLiteral();
+  } else if (scanner->UnescapedLiteralMatches("use strong", 10)) {
+    return PreParserExpression::UseStrongStringLiteral();
   }
   return PreParserExpression::StringLiteral();
 }
 
 
 PreParserExpression PreParserTraits::ParseV8Intrinsic(bool* ok) {
   return pre_parser_->ParseV8Intrinsic(ok);
 }
 
 
@@ skipping 112 matching lines @@
 
   bool directive_prologue = true;
   while (peek() != end_token) {
     if (directive_prologue && peek() != Token::STRING) {
       directive_prologue = false;
     }
     Statement statement = ParseSourceElement(CHECK_OK);
     if (directive_prologue) {
       if (statement.IsUseStrictLiteral()) {
         scope_->SetLanguageMode(
-            static_cast<LanguageMode>(scope_->language_mode() | STRICT));
+            static_cast<LanguageMode>(scope_->language_mode() | STRICT_BIT));
+      } else if (statement.IsUseStrongLiteral() && allow_strong_mode()) {
+        scope_->SetLanguageMode(static_cast<LanguageMode>(
+            scope_->language_mode() | STRICT_BIT | STRONG_BIT));
       } else if (!statement.IsStringLiteral()) {
         directive_prologue = false;
       }
     }
   }
   return kUnknownSourceElements;
 }
 
 
 #undef CHECK_OK
@@ skipping 769 matching lines @@
   }
   if (IsEvalOrArguments(name)) {
     ReportMessageAt(class_name_location, "strict_eval_arguments");
     *ok = false;
     return EmptyExpression();
   }
 
   PreParserScope scope = NewScope(scope_, BLOCK_SCOPE);
   BlockState block_state(&scope_, &scope);
   scope_->SetLanguageMode(
-      static_cast<LanguageMode>(scope_->language_mode() | STRICT));
+      static_cast<LanguageMode>(scope_->language_mode() | STRICT_BIT));
   scope_->SetScopeName(name);
 
   bool has_extends = Check(Token::EXTENDS);
   if (has_extends) {
     ParseLeftHandSideExpression(CHECK_OK);
   }
 
   ClassLiteralChecker checker(this);
   bool has_seen_constructor = false;
 
@@ skipping 26 matching lines @@
   ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ParseArguments(ok);
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal