1/*
2 * Copyright (C) 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#include "config.h"
27#include "AirLowerEntrySwitch.h"
28
29#if ENABLE(B3_JIT)
30
31#include "AirBlockWorklist.h"
32#include "AirCode.h"
33#include "AirInstInlines.h"
34#include "AirPhaseScope.h"
35#include "B3Procedure.h"
36
37namespace JSC { namespace B3 { namespace Air {
38
39void lowerEntrySwitch(Code& code)
40{
41 PhaseScope phaseScope(code, "lowerEntrySwitch");
42
43 // Figure out the set of blocks that should be duplicated.
44 BlockWorklist worklist;
45 for (BasicBlock* block : code) {
46 if (block->last().kind.opcode == EntrySwitch)
47 worklist.push(block);
48 }
49
50 // It's possible that we don't have any EntrySwitches. That's fine.
51 if (worklist.seen().isEmpty()) {
52 Vector<FrequentedBlock> entrypoints(code.proc().numEntrypoints(), FrequentedBlock(code[0]));
53 code.setEntrypoints(WTFMove(entrypoints));
54 return;
55 }
56
57 while (BasicBlock* block = worklist.pop())
58 worklist.pushAll(block->predecessors());
59
60 RELEASE_ASSERT(worklist.saw(code[0]));
61
62 Vector<FrequencyClass> entrypointFrequencies(code.proc().numEntrypoints(), FrequencyClass::Rare);
63 for (BasicBlock* block : code) {
64 if (block->last().kind.opcode != EntrySwitch)
65 continue;
66 for (unsigned entrypointIndex = code.proc().numEntrypoints(); entrypointIndex--;) {
67 entrypointFrequencies[entrypointIndex] = maxFrequency(
68 entrypointFrequencies[entrypointIndex],
69 block->successor(entrypointIndex).frequency());
70 }
71 }
72
73 auto fixEntrySwitch = [&] (BasicBlock* block, unsigned entrypointIndex) {
74 if (block->last().kind.opcode != EntrySwitch)
75 return;
76 FrequentedBlock target = block->successor(entrypointIndex);
77 block->last().kind.opcode = Jump;
78 block->successors().resize(1);
79 block->successor(0) = target;
80 };
81
82 // Now duplicate them.
83 Vector<FrequentedBlock> entrypoints;
84 entrypoints.append(FrequentedBlock(code[0], entrypointFrequencies[0]));
85 IndexMap<BasicBlock*, BasicBlock*> map(code.size());
86 for (unsigned entrypointIndex = 1; entrypointIndex < code.proc().numEntrypoints(); ++entrypointIndex) {
87 map.clear();
88 for (BasicBlock* block : worklist.seen().values(code))
89 map[block] = code.addBlock(block->frequency());
90 entrypoints.append(FrequentedBlock(map[code[0]], entrypointFrequencies[entrypointIndex]));
91 for (BasicBlock* block : worklist.seen().values(code)) {
92 BasicBlock* newBlock = map[block];
93 for (const Inst& inst : *block)
94 newBlock->appendInst(inst);
95 newBlock->successors() = block->successors();
96 for (BasicBlock*& successor : newBlock->successorBlocks()) {
97 if (BasicBlock* replacement = map[successor])
98 successor = replacement;
99 }
100 fixEntrySwitch(newBlock, entrypointIndex);
101 }
102 }
103 for (BasicBlock* block : worklist.seen().values(code))
104 fixEntrySwitch(block, 0);
105
106 code.setEntrypoints(WTFMove(entrypoints));
107 code.resetReachability();
108}
109
110} } } // namespace JSC::B3::Air
111
112#endif // ENABLE(B3_JIT)
113
114
115