Revert of [regexp] Port RegExpExec

src/js/regexp.js

Index: src/js/regexp.js
diff --git a/src/js/regexp.js b/src/js/regexp.js
index 77198d0bf583a7ed456cafe4afe4d86bca9825dc..b9d0f50b244345c52e73e1cb33fdbe09d7c3c6f6 100644
--- a/src/js/regexp.js
+++ b/src/js/regexp.js
@@ -24,7 +24,6 @@
 var speciesSymbol = utils.ImportNow("species_symbol");
 var splitSymbol = utils.ImportNow("split_symbol");
 var SpeciesConstructor;
-var RegExpSubclassExecJS;
 
 utils.Import(function(from) {
   ExpandReplacement = from.ExpandReplacement;
@@ -114,6 +113,53 @@
   regexp.lastIndex = 0;
   return null;
 }
+
+
+// ES#sec-regexp.prototype.exec
+// RegExp.prototype.exec ( string )
+function RegExpSubclassExecJS(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 global = TO_BOOLEAN(REGEXP_GLOBAL(this));
+  var sticky = TO_BOOLEAN(REGEXP_STICKY(this));
+  var updateLastIndex = global || sticky;
+  if (updateLastIndex) {
+    if (i > string.length) {
+      this.lastIndex = 0;
+      return null;
+    }
+  } else {
+    i = 0;
+  }
+
+  // matchIndices is either null or the RegExpLastMatchInfo array.
+  // TODO(littledan): Whether a RegExp is sticky is compiled into the RegExp
+  // itself, but ES2015 allows monkey-patching this property to differ from
+  // the internal flags. If it differs, recompile a different RegExp?
+  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);
+}
+%FunctionRemovePrototype(RegExpSubclassExecJS);
 
 
 // ES#sec-regexpexec Runtime Semantics: RegExpExec ( R, S )
@@ -728,6 +774,7 @@
 // -------------------------------------------------------------------
 
 utils.InstallFunctions(GlobalRegExp.prototype, DONT_ENUM, [
+  "exec", RegExpSubclassExecJS,
   "test", RegExpSubclassTest,
   matchSymbol, RegExpSubclassMatch,
   replaceSymbol, RegExpSubclassReplace,
@@ -737,8 +784,6 @@
 
 // Temporary until all RegExpLastMatchInfo accesses are ported to C++.
 SET_PRIVATE(GlobalRegExp, lastMatchInfoSymbol, RegExpLastMatchInfo);
-
-var RegExpSubclassExecJS = GlobalRegExp.prototype.exec;
 
 // -------------------------------------------------------------------
 // Internal