Fix illegal escape-sequences to throw syntax errors.

src/scanner.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 593 matching lines @@
     // This function is only called to seek to the location
     // of the end of a function (at the "}" token). It doesn't matter
     // whether there was a line terminator in the part we skip.
     has_line_terminator_before_next_ = false;
     has_multiline_comment_before_next_ = false;
   }
   Scan();
 }
 
 
-void Scanner::ScanEscape() {
+bool Scanner::ScanEscape() {
   uc32 c = c0_;
   Advance();
 
   // Skip escaped newlines.
   if (unicode_cache_->IsLineTerminator(c)) {
     // Allow CR+LF newlines in multiline string literals.
     if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance();
     // Allow LF+CR newlines in multiline string literals.
     if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance();
-    return;
+    return true;
   }
 
   switch (c) {
     case '\'':  // fall through
     case '"' :  // fall through
     case '\\': break;
     case 'b' : c = '\b'; break;
     case 'f' : c = '\f'; break;
     case 'n' : c = '\n'; break;
     case 'r' : c = '\r'; break;
     case 't' : c = '\t'; break;
     case 'u' : {
       c = ScanHexNumber(4);
-      if (c < 0) c = 'u';
+      if (c < 0) return false;
       break;
     }
     case 'v' : c = '\v'; break;
     case 'x' : {
       c = ScanHexNumber(2);
-      if (c < 0) c = 'x';
+      if (c < 0) return false;
       break;
     }
     case '0' :  // fall through
     case '1' :  // fall through
     case '2' :  // fall through
     case '3' :  // fall through
     case '4' :  // fall through
     case '5' :  // fall through
     case '6' :  // fall through
     case '7' : c = ScanOctalEscape(c, 2); break;
   }
 
-  // According to ECMA-262, 3rd, 7.8.4 (p 18ff) these
-  // should be illegal, but they are commonly handled
-  // as non-escaped characters by JS VMs.
+  // According to ECMA-262, section 7.8.4, characters not covered by the
+  // above cases should be illegal, but they are commonly handled as
+  // non-escaped characters by JS VMs.
   AddLiteralChar(c);
+  return true;
 }
 
 
 // Octal escapes of the forms '\0xx' and '\xxx' are not a part of
 // ECMA-262. Other JS VMs support them.
 uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
   uc32 x = c - '0';
   int i = 0;
   for (; i < length; i++) {
     int d = c0_ - '0';
@@ skipping 18 matching lines @@
 Token::Value Scanner::ScanString() {
   uc32 quote = c0_;
   Advance();  // consume quote
 
   LiteralScope literal(this);
   while (c0_ != quote && c0_ >= 0
          && !unicode_cache_->IsLineTerminator(c0_)) {
     uc32 c = c0_;
     Advance();
     if (c == '\\') {
-      if (c0_ < 0) return Token::ILLEGAL;
-      ScanEscape();
+      if (c0_ < 0 || !ScanEscape()) return Token::ILLEGAL;
     } else {
       AddLiteralChar(c);
     }
   }
   if (c0_ != quote) return Token::ILLEGAL;
   literal.Complete();
 
   Advance();  // consume quote
   return Token::STRING;
 }
@@ skipping 368 matching lines @@
       }
     }
   }
   literal.Complete();
 
   next_.location.end_pos = source_pos() - 1;
   return true;
 }
 
 } }  // namespace v8::internal