ProgramPoints.java revision 953:221a84ef44c0 
1/*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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25package jdk.nashorn.internal.codegen;
26
27import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.FIRST_PROGRAM_POINT;
28import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.MAX_PROGRAM_POINT_VALUE;
29
30import java.util.HashSet;
31import java.util.Set;
32import jdk.nashorn.internal.IntDeque;
33import jdk.nashorn.internal.ir.AccessNode;
34import jdk.nashorn.internal.ir.BinaryNode;
35import jdk.nashorn.internal.ir.CallNode;
36import jdk.nashorn.internal.ir.Expression;
37import jdk.nashorn.internal.ir.FunctionNode;
38import jdk.nashorn.internal.ir.IdentNode;
39import jdk.nashorn.internal.ir.IndexNode;
40import jdk.nashorn.internal.ir.LexicalContext;
41import jdk.nashorn.internal.ir.Node;
42import jdk.nashorn.internal.ir.Optimistic;
43import jdk.nashorn.internal.ir.UnaryNode;
44import jdk.nashorn.internal.ir.VarNode;
45import jdk.nashorn.internal.ir.visitor.NodeVisitor;
46
47/**
48 * Find program points in the code that are needed for optimistic assumptions
49 */
50class ProgramPoints extends NodeVisitor<LexicalContext> {
51
52    private final IntDeque nextProgramPoint = new IntDeque();
53    private final Set<Node> noProgramPoint = new HashSet<>();
54
55    ProgramPoints() {
56        super(new LexicalContext());
57    }
58
59    private int next() {
60        final int next = nextProgramPoint.getAndIncrement();
61        if(next > MAX_PROGRAM_POINT_VALUE) {
62            throw new AssertionError("Function has more than " + MAX_PROGRAM_POINT_VALUE + " program points");
63        }
64        return next;
65    }
66
67    @Override
68    public boolean enterFunctionNode(final FunctionNode functionNode) {
69        nextProgramPoint.push(FIRST_PROGRAM_POINT);
70        return true;
71    }
72
73    @Override
74    public Node leaveFunctionNode(final FunctionNode functionNode) {
75        nextProgramPoint.pop();
76        return functionNode;
77    }
78
79    private Expression setProgramPoint(final Optimistic optimistic) {
80        if (noProgramPoint.contains(optimistic)) {
81            return (Expression)optimistic;
82        }
83        return (Expression)(optimistic.canBeOptimistic() ? optimistic.setProgramPoint(next()) : optimistic);
84    }
85
86    @Override
87    public boolean enterVarNode(final VarNode varNode) {
88        noProgramPoint.add(varNode.getAssignmentDest());
89        return true;
90    }
91
92    @Override
93    public boolean enterIdentNode(final IdentNode identNode) {
94        if (identNode.isInternal()) {
95            noProgramPoint.add(identNode);
96        }
97        return true;
98    }
99
100    @Override
101    public Node leaveIdentNode(final IdentNode identNode) {
102        if(identNode.isPropertyName()) {
103            return identNode;
104        }
105        return setProgramPoint(identNode);
106    }
107
108    @Override
109    public Node leaveCallNode(final CallNode callNode) {
110        return setProgramPoint(callNode);
111    }
112
113    @Override
114    public Node leaveAccessNode(final AccessNode accessNode) {
115        return setProgramPoint(accessNode);
116    }
117
118    @Override
119    public Node leaveIndexNode(final IndexNode indexNode) {
120        return setProgramPoint(indexNode);
121    }
122
123    @Override
124    public Node leaveBinaryNode(final BinaryNode binaryNode) {
125        return setProgramPoint(binaryNode);
126    }
127
128    @Override
129    public Node leaveUnaryNode(final UnaryNode unaryNode) {
130        return setProgramPoint(unaryNode);
131    }
132}
133