1/*
2 * Copyright (C) 2014, 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
30#include <wtf/PrintStream.h>
31
32namespace JSC { namespace DFG {
33
34enum ValueStrength {
35 // The value has been used for optimization and it arose through inference. We don't want the
36 // fact that we optimized the code to result in the GC keeping this value alive unnecessarily,
37 // so we'd rather kill the code and recompile than keep the object alive longer.
38 WeakValue,
39
40 // The code will keep this value alive. This is true of constants that were present in the
41 // source. String constants tend to be strong.
42 StrongValue
43};
44
45inline ValueStrength merge(ValueStrength a, ValueStrength b)
46{
47 switch (a) {
48 case WeakValue:
49 return b;
50 case StrongValue:
51 return StrongValue;
52 }
53 RELEASE_ASSERT_NOT_REACHED();
54
55 return WeakValue;
56}
57
58} } // namespace JSC::DFG
59
60namespace WTF {
61
62void printInternal(PrintStream&, JSC::DFG::ValueStrength);
63
64} // namespace WTF
65
66#endif // ENABLE(DFG_JIT)
67