1/*
2 * Copyright (C) 2013 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 FTLLoweredNodeValue_h
27#define FTLLoweredNodeValue_h
28
29#if ENABLE(FTL_JIT)
30
31#include "DFGBasicBlock.h"
32#include "FTLAbbreviatedTypes.h"
33
34namespace JSC { namespace FTL {
35
36// Represents the act of having lowered a DFG::Node to an LValue, and records the
37// DFG::BasicBlock that did the lowering. The LValue is what we use most often, but
38// we need to verify that we're in a block that is dominated by the one that did
39// the lowering. We're guaranteed that for each DFG::Node, there will be one
40// LoweredNodeValue that always dominates all uses of the DFG::Node; but there may
41// be others that don't dominate and we're effectively doing opportunistic GVN on
42// the lowering code.
43
44class LoweredNodeValue {
45public:
46    LoweredNodeValue()
47        : m_value(0)
48        , m_block(0)
49    {
50    }
51
52    LoweredNodeValue(LValue value, DFG::BasicBlock* block)
53        : m_value(value)
54        , m_block(block)
55    {
56        ASSERT(m_value);
57        ASSERT(m_block);
58    }
59
60    bool isSet() const { return !!m_value; }
61    bool operator!() const { return !isSet(); }
62
63    LValue value() const { return m_value; }
64    DFG::BasicBlock* block() const { return m_block; }
65
66private:
67    LValue m_value;
68    DFG::BasicBlock* m_block;
69};
70
71} } // namespace JSC::FTL
72
73#endif // ENABLE(FTL_JIT)
74
75#endif // FTLLoweredNodeValue_h
76
77