8e0cd6db8a
This adds a check to the fast case string add to ensure that the String object still have the default valueOf function. The default valueOf is sitting on a hidden prototype of String.prototype. Before using the fast case valueOf the object is checked for a local valueOf property. For slow case objects this check always reports true (the dictionary is not probed, so valueOf might be there) and for fast case objects the descriptor array is checked for the valueOf symbol (just liniar scan). After that the prototype is checked for beeing the initial value of String.prototype. If this all pass (that is the default valueOf is still in place) this result is cached on the map making the check fast the next time. This is only implemented in the optimizing compiler, as the two usages of %_IsStringWrapperSafeForDefaultValueOf is never hit by the full compiler. I will port to x64 and ARM when this has been reviewed for ia32. I will remove the performance counters prior to final commit. BUG=http://code.google.com/p/v8/issues/detail?id=760 TEST=test/mjsunit/regress/regress-760-1.js TEST=test/mjsunit/regress/regress-760-2.js Review URL: http://codereview.chromium.org/3117006 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5252 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
50 lines
2.1 KiB
JavaScript
50 lines
2.1 KiB
JavaScript
// Copyright 2010 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Check that when valueOf for a String object is overwritten it is called and
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// the result used when that object is added with a string.
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// See: http://code.google.com/p/v8/issues/detail?id=760
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String.prototype.valueOf = function() { return 'y' };
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function test() {
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var o = Object('x');
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assertEquals('y', o + '');
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assertEquals('y', '' + o);
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}
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for (var i = 0; i < 10; i++) {
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var o = Object('x');
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assertEquals('y', o + '');
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assertEquals('y', '' + o);
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}
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for (var i = 0; i < 10; i++) {
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test()
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}
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