RegExp: Fix caching to correctly set lastIndex.

test/mjsunit/regress/regress-52801.js

Index: test/mjsunit/regress/regress-52801.js
diff --git a/test/mjsunit/regress/regress-52801.js b/test/mjsunit/regress/regress-52801.js
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+// Copyright 2010 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.
+
+// Whenever we enter a with-scope, we copy the context. This in itself is fine
+// (contexts may escape), but when leaving a with-scope, we currently also copy
+// the context instead of reverting to the original. This does not work because
+// inner functions may already have been created using the original context. In
+// the failing test case below, the inner function is run in the original context
+// (where x is undefined), but the assignment to x after the with-statement is
+// run in the copied context:
+
+// RegExp caching doesn't set lastIndex correctly.
+// See http://code.google.com/p/chromium/issues/detail?id=52801
+
+var re = /a/g;
+
+var str = "bbbbabbbbabbbb";
+
+// Test
+
+re.test(str);
+assertEquals(5, re.lastIndex);
+
+re.lastIndex = 0;
+re.test(str);
+assertEquals(5, re.lastIndex);  // Fails if caching.
+
+re.lastIndex = 0;
+re.test(str);
+assertEquals(5, re.lastIndex);  // Fails if caching.
+
+// Exec
+
+re = /a/g;
+
+re.exec(str);
+assertEquals(5, re.lastIndex);
+
+re.lastIndex = 0;
+re.exec(str);
+assertEquals(5, re.lastIndex);  // Fails if caching.
+
+re.lastIndex = 0;
+re.exec(str);
+assertEquals(5, re.lastIndex);  // Fails if caching.
+
+