1/*
2 * Copyright (C) 2015-2016 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 "DFGBlockMap.h"
31#include "DFGGraph.h"
32
33namespace JSC { namespace DFG {
34
35// Returns the set of nodes live at head, both due to DFG and due to bytecode (i.e. OSR exit).
36NodeSet liveNodesAtHead(Graph&, BasicBlock*);
37
38// WARNING: This currently does not reason about the liveness of shadow values. The execution
39// semantics of DFG SSA are that an Upsilon stores to the shadow value of a Phi, and the Phi loads
40// from that shadow value. Hence, the shadow values are like variables, and have liveness. The normal
41// liveness analysis will tell you about the liveness of shadow values. It's OK to ignore shadow
42// values if you treat Upsilon as an opaque escape, and all of the clients of CombinedLiveness do so.
43struct CombinedLiveness {
44 CombinedLiveness() { }
45
46 CombinedLiveness(Graph&);
47
48 BlockMap<NodeSet> liveAtHead;
49 BlockMap<NodeSet> liveAtTail;
50};
51
52} } // namespace JSC::DFG
53
54#endif // ENABLE(DFG_JIT)
55