Tentative implementation of string slices (hidden under the flag --string-slices).

test/mjsunit/string-slices-regex.js

Index: test/mjsunit/string-slices-regex.js
diff --git a/test/mjsunit/string-slices-regex.js b/test/mjsunit/string-slices-regex.js
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+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Flags: --string-slices
+
+var re = /^(((N({)?)|(R)|(U)|(V)|(B)|(H)|(n((n)|(r)|(v)|(h))?)|(r(r)?)|(v)|(b((n)|(b))?)|(h))|((Y)|(A)|(E)|(o(u)?)|(p(u)?)|(q(u)?)|(s)|(t)|(u)|(w)|(x(u)?)|(y)|(z)|(a((T)|(A)|(L))?)|(c)|(e)|(f(u)?)|(g(u)?)|(i)|(j)|(l)|(m(u)?)))+/;
+var r = new RegExp(re)
+var str = "_Avtnennan gunzvmu pubExnY nEvln vaTxh rmuhguhaTxnY_".slice(1,-1);
+str = str + str;
+assertTrue(r.test(str));
+assertTrue(r.test(str));
+var re = /x/;
+assertEquals("a.yb", "_axyb_".slice(1,-1).replace(re, "."));
+re.compile("y");
+assertEquals("ax.b", "_axyb_".slice(1,-1).replace(re, "."));
+re.compile("(x)");
+assertEquals(["x", "x"], re.exec("_axyb_".slice(1,-1)));
+
+re.compile("(y)");
+assertEquals(["y", "y"], re.exec("_axyb_".slice(1,-1)));
+
+var a = "_bbaababbabaaaaabbaaaabba_".slice(1,-1);
+var b = "bbaababbabaaaaabbaaaabba" + a;
+// The first time, the slice will be truncated and handled by the
+// runtime system.
+assertEquals(["bbaa", "a", "", "a"], /((\3|b)\2(a)){2,}/.exec(a));
+// The second time, the slice is already truncated and will be handled
+// by generated code.
+assertEquals(["bbaa", "a", "", "a"], /((\3|b)\2(a)){2,}/.exec(a));
+// The first time, the cons string will be flattened and handled by the
+// runtime system.
+assertEquals(["bbaa", "a", "", "a"], /((\3|b)\2(a)){2,}/.exec(b));
+// The second time, the cons string is already flattened and will be
+// handled by generated code.
+assertEquals(["bbaa", "a", "", "a"], /((\3|b)\2(a)){2,}/.exec(b));
+
+var c = "ABCDEFGHIJKLMN".slice(2,-2);
+var d = "ABCDEF\u1234GHIJKLMN".slice(2,-2);
+assertTrue(/^C.*L$/.test(c));
+assertTrue(/^C.*L$/.test(c));
+assertTrue(/^C.*L$/.test(d));
+assertTrue(/^C.*L$/.test(d));