1/*
2 * Copyright (C) 2016-2018 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 "B3BreakCriticalEdges.h"
28
29#if ENABLE(B3_JIT)
30
31#include "B3BasicBlockInlines.h"
32#include "B3BlockInsertionSet.h"
33#include "B3ProcedureInlines.h"
34#include "B3ValueInlines.h"
35
36namespace JSC { namespace B3 {
37
38void breakCriticalEdges(Procedure& proc)
39{
40 BlockInsertionSet insertionSet(proc);
41
42 for (BasicBlock* block : proc) {
43 // Non-void terminals that are the moral equivalent of jumps trigger critical edge breaking
44 // because of fixSSA's demoteValues.
45 if (block->numSuccessors() <= 1
46 && block->last()->type() == Void)
47 continue;
48
49 for (BasicBlock*& successor : block->successorBlocks()) {
50 if (successor->numPredecessors() <= 1)
51 continue;
52
53 BasicBlock* pad =
54 insertionSet.insertBefore(successor, successor->frequency());
55 pad->appendNew<Value>(proc, Jump, successor->at(0)->origin());
56 pad->setSuccessors(FrequentedBlock(successor));
57 pad->addPredecessor(block);
58 successor->replacePredecessor(block, pad);
59 successor = pad;
60 }
61 }
62
63 if (insertionSet.execute())
64 proc.invalidateCFG();
65}
66
67} } // namespace JSC::B3
68
69#endif // ENABLE(B3_JIT)
70
71