[regexp] Add support for dotAll flag

src/objects.cc

 // Copyright 2015 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 "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 16122 matching lines @@
     switch (flags->Get(i)) {
       case 'g':
         flag = JSRegExp::kGlobal;
         break;
       case 'i':
         flag = JSRegExp::kIgnoreCase;
         break;
       case 'm':
         flag = JSRegExp::kMultiline;
         break;
+      case 's':
+        if (FLAG_harmony_regexp_dotall) {
+          flag = JSRegExp::kDotAll;
+        } else {
+          return JSRegExp::Flags(0);
+        }
+        break;
       case 'u':
         flag = JSRegExp::kUnicode;
         break;
       case 'y':
         flag = JSRegExp::kSticky;
         break;
       default:
         return JSRegExp::Flags(0);
     }
     // Duplicate flag.
@@ skipping 4241 matching lines @@
       // depend on this.
       return DICTIONARY_ELEMENTS;
     }
     DCHECK_LE(kind, LAST_ELEMENTS_KIND);
     return kind;
   }
 }
 
 }  // namespace internal
 }  // namespace v8