Fire 'stack' getter of error objects after GC.

test/mjsunit/stack-traces-gc.js

Index: test/mjsunit/stack-traces-gc.js
diff --git a/test/mjsunit/stack-traces-gc.js b/test/mjsunit/stack-traces-gc.js
new file mode 100644
index 0000000000000000000000000000000000000000..dd878f23b5b258342ccd5d766c63a0f8adbd4b7b
--- /dev/null
+++ b/test/mjsunit/stack-traces-gc.js
@@ -0,0 +1,119 @@
+// Copyright 2012 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: --expose-gc --allow-natives-syntax
+
+var fired = [];
+for (var i = 0; i < 100; i++) fired[i] = false;
+
+function getter_function(i) {
+  return %MarkOneShotGetter( function() { fired[i] = true; } );
+}
+
+// Error objects that die young.
+for (var i = 0; i < 100; i++) {
+  var error = new Error();
+  // Replace the getter to observe whether it has been fired,
+  // and disguise it as original getter.
+  var getter = getter_function(i);
+  error.__defineGetter__("stack", getter);
+
+  error = undefined;
+}
+
+gc();
+for (var i = 0; i < 100; i++) {
+  assertFalse(fired[i]);
+}
+
+// Error objects that are kept alive.
+var array = [];
+for (var i = 0; i < 100; i++) {
+  var error = new Error();
+  var getter = getter_function(i);
+  // Replace the getter to observe whether it has been fired,
+  // and disguise it as original getter.
+  error.__defineGetter__("stack", getter);
+
+  array.push(error);
+  error = undefined;
+}
+
+gc();
+// We don't expect all stack traces to be formatted after only one GC.
+assertTrue(fired[0]);
+
+for (var i = 0; i < 10; i++) gc();
+for (var i = 0; i < 100; i++) assertTrue(fired[i]);
+
+// Error objects with custom stack getter.
+var custom_error = new Error();
+var custom_getter_fired = false;
+custom_error.__defineGetter__("stack",
+                              function() { custom_getter_fired = true; });
+gc();
+assertFalse(custom_getter_fired);
+
+// Check that formatting caused by GC is not somehow observable.
+var error;
+
+var obj = { foo: function foo() { throw new Error(); } };
+
+try {
+  obj.foo();
+} catch (e) {
+  delete obj.foo;
+  Object.defineProperty(obj, 'foo', {
+    get: function() { assertUnreachable(); }
+  });
+  error = e;
+}
+
+gc();
+
+Object.defineProperty(Array.prototype, '0', {
+  get: function() { assertUnreachable(); }
+});
+
+try {
+  throw new Error();
+} catch (e) {
+  error = e;
+}
+
+gc();
+
+String.prototype.indexOf = function() { assertUnreachable(); };
+String.prototype.lastIndexOf = function() { assertUnreachable(); };
+var obj = { method: function() { throw Error(); } };
+try {
+  obj.method();
+} catch (e) {
+  error = e;
+}
+
+gc();