[regexp] Merge exec implementations

src/js/regexp.js

Index: src/js/regexp.js
diff --git a/src/js/regexp.js b/src/js/regexp.js
index b9b096492b754095d41056f72e82411e49376e13..bde4c1fa2d3ce187f7b74c912a0b7576ff20d5e4 100644
--- a/src/js/regexp.js
+++ b/src/js/regexp.js
@@ -207,46 +207,6 @@ function RegExpSubclassExecJS(string) {
 %FunctionRemovePrototype(RegExpSubclassExecJS);
 
 
-// Legacy implementation of RegExp.prototype.exec
-function RegExpExecJS(string) {
-  if (!IS_REGEXP(this)) {
-    throw %make_type_error(kIncompatibleMethodReceiver,
-                        'RegExp.prototype.exec', this);
-  }
-
-  string = TO_STRING(string);
-  var lastIndex = this.lastIndex;
-
-  // Conversion is required by the ES2015 specification (RegExpBuiltinExec
-  // algorithm, step 4) even if the value is discarded for non-global RegExps.
-  var i = TO_LENGTH(lastIndex);
-
-  var updateLastIndex = REGEXP_GLOBAL(this) || REGEXP_STICKY(this);
-  if (updateLastIndex) {
-    if (i < 0 || i > string.length) {
-      this.lastIndex = 0;
-      return null;
-    }
-  } else {
-    i = 0;
-  }
-
-  // matchIndices is either null or the RegExpLastMatchInfo array.
-  var matchIndices = %_RegExpExec(this, string, i, RegExpLastMatchInfo);
-
-  if (IS_NULL(matchIndices)) {
-    this.lastIndex = 0;
-    return null;
-  }
-
-  // Successful match.
-  if (updateLastIndex) {
-    this.lastIndex = RegExpLastMatchInfo[CAPTURE1];
-  }
-  RETURN_NEW_RESULT_FROM_MATCH_INFO(matchIndices, string);
-}
-
-
 // ES#sec-regexpexec Runtime Semantics: RegExpExec ( R, S )
 // Also takes an optional exec method in case our caller
 // has already fetched exec.
@@ -261,7 +221,7 @@ function RegExpSubclassExec(regexp, string, exec) {
     }
     return result;
   }
-  return %_Call(RegExpExecJS, regexp, string);
+  return %_Call(RegExpSubclassExecJS, regexp, string);
 }
 %SetForceInlineFlag(RegExpSubclassExec);