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1 | /* | |
2 | * Copyright (C) 2013, 2014 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 "DFGOSREntrypointCreationPhase.h" | |
28 | ||
29 | #if ENABLE(DFG_JIT) | |
30 | ||
31 | #include "DFGBasicBlockInlines.h" | |
32 | #include "DFGBlockInsertionSet.h" | |
33 | #include "DFGGraph.h" | |
34 | #include "DFGLoopPreHeaderCreationPhase.h" | |
35 | #include "DFGPhase.h" | |
36 | #include "JSCInlines.h" | |
37 | ||
38 | namespace JSC { namespace DFG { | |
39 | ||
40 | class OSREntrypointCreationPhase : public Phase { | |
41 | public: | |
42 | OSREntrypointCreationPhase(Graph& graph) | |
43 | : Phase(graph, "OSR entrypoint creation") | |
44 | { | |
45 | } | |
46 | ||
47 | bool run() | |
48 | { | |
49 | RELEASE_ASSERT(m_graph.m_plan.mode == FTLForOSREntryMode); | |
50 | RELEASE_ASSERT(m_graph.m_form == ThreadedCPS); | |
51 | ||
52 | unsigned bytecodeIndex = m_graph.m_plan.osrEntryBytecodeIndex; | |
53 | RELEASE_ASSERT(bytecodeIndex); | |
54 | RELEASE_ASSERT(bytecodeIndex != UINT_MAX); | |
55 | ||
56 | // Needed by createPreHeader(). | |
57 | m_graph.m_dominators.computeIfNecessary(m_graph); | |
58 | ||
59 | CodeBlock* baseline = m_graph.m_profiledBlock; | |
60 | ||
61 | BasicBlock* target = 0; | |
62 | for (unsigned blockIndex = m_graph.numBlocks(); blockIndex--;) { | |
63 | BasicBlock* block = m_graph.block(blockIndex); | |
64 | if (!block) | |
65 | continue; | |
66 | unsigned nodeIndex = 0; | |
67 | Node* firstNode = block->at(0); | |
68 | while (firstNode->isSemanticallySkippable()) | |
69 | firstNode = block->at(++nodeIndex); | |
70 | if (firstNode->op() == LoopHint | |
71 | && firstNode->origin.semantic == CodeOrigin(bytecodeIndex)) { | |
72 | target = block; | |
73 | break; | |
74 | } | |
75 | } | |
76 | ||
77 | if (!target) { | |
78 | // This is a terrible outcome. It shouldn't often happen but it might | |
79 | // happen and so we should defend against it. If it happens, then this | |
80 | // compilation is a failure. | |
81 | return false; | |
82 | } | |
83 | ||
84 | BlockInsertionSet insertionSet(m_graph); | |
85 | ||
86 | // We say that the execution count of the entry block is 1, because we know for sure | |
87 | // that this must be the case. Under our definition of executionCount, "1" means "once | |
88 | // per invocation". We could have said NaN here, since that would ask any clients of | |
89 | // executionCount to use best judgement - but that seems unnecessary since we know for | |
90 | // sure what the executionCount should be in this case. | |
91 | BasicBlock* newRoot = insertionSet.insert(0, 1); | |
92 | NodeOrigin origin = target->at(0)->origin; | |
93 | ||
94 | Vector<Node*> locals(baseline->m_numCalleeRegisters); | |
95 | for (int local = 0; local < baseline->m_numCalleeRegisters; ++local) { | |
96 | Node* previousHead = target->variablesAtHead.local(local); | |
97 | if (!previousHead) | |
98 | continue; | |
99 | VariableAccessData* variable = previousHead->variableAccessData(); | |
100 | locals[local] = newRoot->appendNode( | |
101 | m_graph, variable->prediction(), ExtractOSREntryLocal, origin, | |
102 | OpInfo(variable->local().offset())); | |
103 | ||
104 | newRoot->appendNode( | |
105 | m_graph, SpecNone, MovHint, origin, OpInfo(variable->local().offset()), | |
106 | Edge(locals[local])); | |
107 | } | |
108 | ||
109 | for (int argument = 0; argument < baseline->numParameters(); ++argument) { | |
110 | Node* oldNode = target->variablesAtHead.argument(argument); | |
111 | if (!oldNode) { | |
112 | // Just for sanity, always have a SetArgument even if it's not needed. | |
113 | oldNode = m_graph.m_arguments[argument]; | |
114 | } | |
115 | Node* node = newRoot->appendNode( | |
116 | m_graph, SpecNone, SetArgument, origin, | |
117 | OpInfo(oldNode->variableAccessData())); | |
118 | m_graph.m_arguments[argument] = node; | |
119 | } | |
120 | ||
121 | for (int local = 0; local < baseline->m_numCalleeRegisters; ++local) { | |
122 | Node* previousHead = target->variablesAtHead.local(local); | |
123 | if (!previousHead) | |
124 | continue; | |
125 | VariableAccessData* variable = previousHead->variableAccessData(); | |
126 | Node* node = locals[local]; | |
127 | newRoot->appendNode( | |
128 | m_graph, SpecNone, SetLocal, origin, OpInfo(variable), Edge(node)); | |
129 | } | |
130 | ||
131 | newRoot->appendNode( | |
132 | m_graph, SpecNone, Jump, origin, | |
133 | OpInfo(createPreHeader(m_graph, insertionSet, target))); | |
134 | ||
135 | insertionSet.execute(); | |
136 | m_graph.resetReachability(); | |
137 | m_graph.killUnreachableBlocks(); | |
138 | return true; | |
139 | } | |
140 | }; | |
141 | ||
142 | bool performOSREntrypointCreation(Graph& graph) | |
143 | { | |
144 | SamplingRegion samplingRegion("DFG OSR Entrypoint Creation"); | |
145 | return runPhase<OSREntrypointCreationPhase>(graph); | |
146 | } | |
147 | ||
148 | } } // namespace JSC::DFG | |
149 | ||
150 | #endif // ENABLE(DFG_JIT) | |
151 | ||
152 |