1/*
2 * Copyright (C) 2015-2018 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#include "config.h"
27#include "DFGCombinedLiveness.h"
28
29#if ENABLE(DFG_JIT)
30
31#include "DFGAvailabilityMap.h"
32#include "DFGBlockMapInlines.h"
33#include "FullBytecodeLiveness.h"
34#include "JSCInlines.h"
35
36namespace JSC { namespace DFG {
37
38static void addBytecodeLiveness(Graph& graph, AvailabilityMap& availabilityMap, NodeSet& seen, Node* node)
39{
40 graph.forAllLiveInBytecode(
41 node->origin.forExit,
42 [&] (VirtualRegister reg) {
43 availabilityMap.closeStartingWithLocal(
44 reg,
45 [&] (Node* node) -> bool {
46 return seen.contains(node);
47 },
48 [&] (Node* node) -> bool {
49 return seen.add(node).isNewEntry;
50 });
51 });
52}
53
54NodeSet liveNodesAtHead(Graph& graph, BasicBlock* block)
55{
56 NodeSet seen;
57 for (NodeFlowProjection node : block->ssa->liveAtHead) {
58 if (node.kind() == NodeFlowProjection::Primary)
59 seen.addVoid(node.node());
60 }
61
62 addBytecodeLiveness(graph, block->ssa->availabilityAtHead, seen, block->at(0));
63 return seen;
64}
65
66CombinedLiveness::CombinedLiveness(Graph& graph)
67 : liveAtHead(graph)
68 , liveAtTail(graph)
69{
70 // First compute
71 // - The liveAtHead for each block.
72 // - The liveAtTail for blocks that won't properly propagate
73 // the information based on their empty successor list.
74 for (BasicBlock* block : graph.blocksInNaturalOrder()) {
75 liveAtHead[block] = liveNodesAtHead(graph, block);
76
77 // If we don't have successors, we can't rely on the propagation below. This doesn't usually
78 // do anything for terminal blocks, since the last node is usually a return, so nothing is live
79 // after it. However, we may also have the end of the basic block be:
80 //
81 // ForceOSRExit
82 // Unreachable
83 //
84 // And things may definitely be live in bytecode at that point in the program.
85 if (!block->numSuccessors()) {
86 NodeSet seen;
87 addBytecodeLiveness(graph, block->ssa->availabilityAtTail, seen, block->last());
88 liveAtTail[block] = seen;
89 }
90 }
91
92 // Now compute the liveAtTail by unifying the liveAtHead of the successors.
93 for (BasicBlock* block : graph.blocksInNaturalOrder()) {
94 for (BasicBlock* successor : block->successors()) {
95 for (Node* node : liveAtHead[successor])
96 liveAtTail[block].addVoid(node);
97 }
98 }
99}
100
101} } // namespace JSC::DFG
102
103#endif // ENABLE(DFG_JIT)
104
105