[regexp] Add support for dotAll flag

test/mjsunit/harmony/regexp-dotall-disabled.js

Index: test/mjsunit/harmony/regexp-dotall-disabled.js
diff --git a/test/mjsunit/harmony/regexp-dotall-disabled.js b/test/mjsunit/harmony/regexp-dotall-disabled.js
new file mode 100644
index 0000000000000000000000000000000000000000..bf50b13f786b691095b9f4b049364289af2fce05
--- /dev/null
+++ b/test/mjsunit/harmony/regexp-dotall-disabled.js
@@ -0,0 +1,67 @@
+// Copyright 2017 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.
+
+// This tests that RegExp dotall features are not enabled when
+// --harmony-regexp-dotall is not passed.
+
+// Construction does not throw.
+{
+  assertThrows("/./s", SyntaxError);
+  assertThrows(() => RegExp(".", "s"), SyntaxError);
+  assertThrows(() => new RegExp(".", "s"), SyntaxError);
+  assertThrows(() => new RegExp(".", "wtf"), SyntaxError);
+}
+
+// The flags accessors.
+{
+  let re = /./gimyu;

[erikcorry, 2017/03/30 13:28:30]

You could also check

("dotAll" in re)

to see if the property is there with value "undefined", or it is really not
there.

[jgruber, 2017/03/31 09:17:00]

Done.

+  assertEquals("gimuy", re.flags);
+  assertTrue(re.global);
+  assertTrue(re.ignoreCase);
+  assertTrue(re.multiline);
+  assertTrue(re.sticky);
+  assertTrue(re.unicode);
+  assertEquals(re.dotAll, undefined);
+
+  let callCount = 0;
+  re.__defineGetter__('dotAll', () => { callCount++; return undefined; });
+  assertEquals("gimuy", re.flags);
+  assertEquals(callCount, 0);
+}
+
+// Default '.' behavior.
+{
+  let re = /^.$/;
+  assertTrue(re.test("a"));
+  assertTrue(re.test("3"));
+  assertTrue(re.test("π"));
+  assertTrue(re.test("\u2027"));
+  assertTrue(re.test("\u0085"));
+  assertTrue(re.test("\v"));
+  assertTrue(re.test("\f"));
+  assertTrue(re.test("\u180E"));
+  assertFalse(re.test("\u{10300}"));  // Supplementary plane.
+  assertFalse(re.test("\n"));
+  assertFalse(re.test("\r"));
+  assertFalse(re.test("\u2028"));
+  assertFalse(re.test("\u2029"));
+}
+
+// Default '.' behavior (unicode).
+{
+  let re = /^.$/u;
+  assertTrue(re.test("a"));
+  assertTrue(re.test("3"));
+  assertTrue(re.test("π"));
+  assertTrue(re.test("\u2027"));
+  assertTrue(re.test("\u0085"));
+  assertTrue(re.test("\v"));
+  assertTrue(re.test("\f"));
+  assertTrue(re.test("\u180E"));
+  assertTrue(re.test("\u{10300}"));  // Supplementary plane.
+  assertFalse(re.test("\n"));
+  assertFalse(re.test("\r"));
+  assertFalse(re.test("\u2028"));
+  assertFalse(re.test("\u2029"));
+}