Fix RegExp.prototype.compile error case

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 <sstream>
 
@@ skipping 15407 matching lines @@
   Isolate* isolate = regexp->GetIsolate();
   Factory* factory = isolate->factory();
   // If source is the empty string we set it to "(?:)" instead as
   // suggested by ECMA-262, 5th, section 15.10.4.1.
   if (source->length() == 0) source = factory->query_colon_string();
 
   Handle<String> escaped_source;
   ASSIGN_RETURN_ON_EXCEPTION(isolate, escaped_source,
                              EscapeRegExpSource(isolate, source), JSRegExp);
 
+  RETURN_ON_EXCEPTION(isolate, RegExpImpl::Compile(regexp, source, flags),
+                      JSRegExp);
+
   regexp->set_source(*escaped_source);
   regexp->set_flags(Smi::FromInt(flags));
 
   Map* map = regexp->map();
   Object* constructor = map->GetConstructor();
   if (constructor->IsJSFunction() &&
       JSFunction::cast(constructor)->initial_map() == map) {
     // If we still have the original map, set in-object properties directly.
     regexp->InObjectPropertyAtPut(JSRegExp::kLastIndexFieldIndex,
                                   Smi::FromInt(0), SKIP_WRITE_BARRIER);
   } else {
     // Map has changed, so use generic, but slower, method.
     PropertyAttributes writable =
         static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE);
     JSObject::SetOwnPropertyIgnoreAttributes(
         regexp, factory->last_index_string(),
         Handle<Smi>(Smi::FromInt(0), isolate), writable)
         .Check();
   }
 
-  RETURN_ON_EXCEPTION(isolate, RegExpImpl::Compile(regexp, source, flags),
-                      JSRegExp);
-
   return regexp;
 }
 
 
 // RegExpKey carries the source and flags of a regular expression as key.
 class RegExpKey : public HashTableKey {
  public:
   RegExpKey(Handle<String> string, JSRegExp::Flags flags)
       : string_(string), flags_(Smi::FromInt(flags)) {}
 
@@ skipping 2814 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8