Revert of Remove RegExp.multiline accessors. (patchset #3 id:40001 of...

Revert of Remove RegExp.multiline accessors. (patchset #3 id:40001 of https://codereview.chromium.org/1410993008/ )

Reason for revert:
[Sheriff] Causes layout test failures.

Original issue's description:
> Remove RegExp.multiline accessors.
>
> This is non-standard and not even documented on MDN.
>
> On Firefox, setting RegExp.multiline to true adds the multiline flag to all
> newly created RegExp objects (both from constructor and from literal).
>
> In V8 this has no effect.
>
> Source archaelogy shows that this is from the initial commit.
>
> R=bmeurer@chromium.org
>
> Committed: https://crrev.com/e8f752ce0c2a488e88cd87fe75f3907b4303d0a0
> Cr-Commit-Position: refs/heads/master@{#31673}

TBR=bmeurer@chromium.org,yangguo@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1431433004

Cr-Commit-Position: refs/heads/master@{#31679}

src/js/regexp.js

@@ -367,6 +367,25 @@ var RegExpSetInput = function(string) {
 %DefineAccessorPropertyUnchecked(GlobalRegExp, '$_', RegExpGetInput,
                                  RegExpSetInput, DONT_ENUM | DONT_DELETE);
 
+// The properties multiline and $* are aliases for each other.  When this
+// value is set in SpiderMonkey, the value it is set to is coerced to a
+// boolean.  We mimic that behavior with a slight difference: in SpiderMonkey
+// the value of the expression 'RegExp.multiline = null' (for instance) is the
+// boolean false (i.e., the value after coercion), while in V8 it is the value
+// null (i.e., the value before coercion).
+
+// Getter and setter for multiline.
+var multiline = false;
+var RegExpGetMultiline = function() { return multiline; };
+var RegExpSetMultiline = function(flag) { multiline = flag ? true : false; };
+
+%DefineAccessorPropertyUnchecked(GlobalRegExp, 'multiline', RegExpGetMultiline,
+                                 RegExpSetMultiline, DONT_DELETE);
+%DefineAccessorPropertyUnchecked(GlobalRegExp, '$*', RegExpGetMultiline,
+                                 RegExpSetMultiline,
+                                 DONT_ENUM | DONT_DELETE);
+
+
 var NoOpSetter = function(ignored) {};
 
 

test/mjsunit/regexp-static.js

@@ -144,6 +144,8 @@ for (var i = 1; i <= 9; i++) {
   assertEquals("", RegExp['$' + (i)], "$" + i);
 }
 
+RegExp.multiline = "foo";
+assertTrue(typeof RegExp.multiline == typeof Boolean(), "RegExp.multiline coerces values to booleans");
 RegExp.input = Number();
 assertTrue(typeof RegExp.input == typeof String(), "RegExp.input coerces values to booleans");
 

test/mozilla/mozilla.status

@@ -91,9 +91,6 @@
   # In ES6, the completion value of a 0-iterations loop is 'undefined'.
   'ecma/Statements/12.6.3-2': [PASS, FAIL],
 
-  # RegExp.multiline is not documented or specified anywhere.
-  'js1_5/Regress/regress-418504': [FAIL],
-
   ##################### SKIPPED TESTS #####################
 
   # This test checks that we behave properly in an out-of-memory