[regexp] correctly parse non-BMP unicode escapes in atoms.

src/regexp/regexp-parser.cc

 // Copyright 2016 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/regexp/regexp-parser.h"
 
 #include "src/char-predicates-inl.h"
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
@@ skipping 399 matching lines @@
               // If the 'u' flag is present, invalid escapes are not treated as
               // identity escapes.
               return ReportError(CStrVector("Invalid escape"));
             }
             break;
           }
           case 'u': {
             Advance(2);
             uc32 value;
             if (ParseUnicodeEscape(&value)) {
-              builder->AddCharacter(value);
+              if (value > unibrow::Utf16::kMaxNonSurrogateCharCode) {
+                builder->AddCharacter(unibrow::Utf16::LeadSurrogate(value));
+                builder->AddCharacter(unibrow::Utf16::TrailSurrogate(value));
+              } else {
+                builder->AddCharacter(static_cast<uc16>(value));
+              }
             } else if (!unicode_) {
               builder->AddCharacter('u');
             } else {
               // If the 'u' flag is present, invalid escapes are not treated as
               // identity escapes.
               return ReportError(CStrVector("Invalid unicode escape"));
             }
             break;
           }
           default:
@@ skipping 548 matching lines @@
                                bool unicode, RegExpCompileData* result) {
   DCHECK(result != NULL);
   RegExpParser parser(input, &result->error, multiline, unicode, isolate, zone);
   RegExpTree* tree = parser.ParsePattern();
   if (parser.failed()) {
     DCHECK(tree == NULL);
     DCHECK(!result->error.is_null());
   } else {
     DCHECK(tree != NULL);
     DCHECK(result->error.is_null());
+    if (FLAG_trace_regexp_parser) {
+      OFStream os(stdout);
+      tree->Print(os, zone);
+      os << "\n";
+    }
     result->tree = tree;
     int capture_count = parser.captures_started();
     result->simple = tree->IsAtom() && parser.simple() && capture_count == 0;
     result->contains_anchor = parser.contains_anchor();
     result->capture_count = capture_count;
   }
   return !parser.failed();
 }
 
 
@@ skipping 144 matching lines @@
     UNREACHABLE();
     return;
   }
   terms_.Add(new (zone()) RegExpQuantifier(min, max, quantifier_type, atom),
              zone());
   LAST(ADD_TERM);
 }
 
 }  // namespace internal
 }  // namespace v8