1/*
2 * Copyright (C) 2013, 2015 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#if ENABLE(DFG_JIT)
29
30namespace JSC { namespace DFG {
31
32// Tells you if an operation that filters type (i.e. does a type check/speculation) will always
33// exit. Formally, this means that the proven type of a value prior to the filter was not
34// bottom (i.e. not "clear" or "SpecEmpty") but becomes bottom as a result of executing the
35// filter.
36//
37// Note that per this definition, a filter will not return Contradiction if the node's proven
38// type was already bottom. This is necessary because we have this yucky convention of using
39// a proven type of bottom for nodes that don't hold JS values, like Phi nodes in ThreadedCPS
40// and storage nodes.
41enum FiltrationResult {
42 // Means that this operation may not always exit.
43 FiltrationOK,
44
45 // Means that this operation will always exit.
46 Contradiction
47};
48
49} } // namespace JSC::DFG
50
51#endif // ENABLE(DFG_JIT)
52