1/*
2 * Copyright (C) 2012 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#ifndef CodeBlockHash_h
27#define CodeBlockHash_h
28
29#include "CodeSpecializationKind.h"
30#include <wtf/PrintStream.h>
31
32// CodeBlock hashes are useful for informally identifying code blocks. They correspond
33// to the low 32 bits of a SHA1 hash of the source code with two low bit flipped
34// according to the role that the code block serves (call, construct). Additionally, the
35// hashes are typically operated over using a string in which the hash is transformed
36// into a 6-byte alphanumeric representation. This can be retrieved by using
37// toString(const CodeBlockHash&). Finally, we support CodeBlockHashes for native
38// functions, in which case the hash is replaced by the function address.
39
40namespace JSC {
41
42class SourceCode;
43
44class CodeBlockHash {
45public:
46 CodeBlockHash()
47 : m_hash(0)
48 {
49 }
50
51 explicit CodeBlockHash(unsigned hash)
52 : m_hash(hash)
53 {
54 }
55
56 CodeBlockHash(const SourceCode&, CodeSpecializationKind);
57
58 explicit CodeBlockHash(const char*);
59
60 bool isSet() const { return !!m_hash; }
61 bool operator!() const { return !isSet(); }
62
63 unsigned hash() const { return m_hash; }
64
65 void dump(PrintStream&) const;
66
67 // Comparison methods useful for bisection.
68 bool operator==(const CodeBlockHash& other) const { return hash() == other.hash(); }
69 bool operator!=(const CodeBlockHash& other) const { return hash() != other.hash(); }
70 bool operator<(const CodeBlockHash& other) const { return hash() < other.hash(); }
71 bool operator>(const CodeBlockHash& other) const { return hash() > other.hash(); }
72 bool operator<=(const CodeBlockHash& other) const { return hash() <= other.hash(); }
73 bool operator>=(const CodeBlockHash& other) const { return hash() >= other.hash(); }
74
75private:
76 unsigned m_hash;
77};
78
79} // namespace JSC
80
81#endif // CodeBlockHash_h
82