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.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package jdk.nashorn.internal.codegen;
  26 
  27 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.FIRST_PROGRAM_POINT;
  28 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.MAX_PROGRAM_POINT_VALUE;
  29 
  30 import java.util.HashSet;
  31 import java.util.Set;
  32 import jdk.nashorn.internal.IntDeque;
  33 import jdk.nashorn.internal.ir.AccessNode;
  34 import jdk.nashorn.internal.ir.BinaryNode;
  35 import jdk.nashorn.internal.ir.CallNode;
  36 import jdk.nashorn.internal.ir.Expression;
  37 import jdk.nashorn.internal.ir.FunctionNode;
  38 import jdk.nashorn.internal.ir.IdentNode;
  39 import jdk.nashorn.internal.ir.IndexNode;
  40 import jdk.nashorn.internal.ir.Node;
  41 import jdk.nashorn.internal.ir.Optimistic;
  42 import jdk.nashorn.internal.ir.UnaryNode;
  43 import jdk.nashorn.internal.ir.VarNode;
  44 import jdk.nashorn.internal.ir.visitor.SimpleNodeVisitor;
  45 
  46 /**
  47  * Find program points in the code that are needed for optimistic assumptions
  48  */
  49 class ProgramPoints extends SimpleNodeVisitor {
  50 
  51     private final IntDeque nextProgramPoint = new IntDeque();
  52     private final Set<Node> noProgramPoint = new HashSet<>();
  53 
  54     private int next() {
  55         final int next = nextProgramPoint.getAndIncrement();
  56         if(next > MAX_PROGRAM_POINT_VALUE) {
  57             throw new AssertionError("Function has more than " + MAX_PROGRAM_POINT_VALUE + " program points");
  58         }
  59         return next;
  60     }
  61 
  62     @Override
  63     public boolean enterFunctionNode(final FunctionNode functionNode) {
  64         nextProgramPoint.push(FIRST_PROGRAM_POINT);
  65         return true;
  66     }
  67 
  68     @Override
  69     public Node leaveFunctionNode(final FunctionNode functionNode) {
  70         nextProgramPoint.pop();
  71         return functionNode;
  72     }
  73 
  74     private Expression setProgramPoint(final Optimistic optimistic) {
  75         if (noProgramPoint.contains(optimistic)) {
  76             return (Expression)optimistic;
  77         }
  78         return (Expression)(optimistic.canBeOptimistic() ? optimistic.setProgramPoint(next()) : optimistic);
  79     }
  80 
  81     @Override
  82     public boolean enterVarNode(final VarNode varNode) {
  83         noProgramPoint.add(varNode.getName());
  84         return true;
  85     }
  86 
  87     @Override
  88     public boolean enterIdentNode(final IdentNode identNode) {
  89         if (identNode.isInternal()) {
  90             noProgramPoint.add(identNode);
  91         }
  92         return true;
  93     }
  94 
  95     @Override
  96     public Node leaveIdentNode(final IdentNode identNode) {
  97         if(identNode.isPropertyName()) {
  98             return identNode;
  99         }
 100         return setProgramPoint(identNode);
 101     }
 102 
 103     @Override
 104     public Node leaveCallNode(final CallNode callNode) {
 105         return setProgramPoint(callNode);
 106     }
 107 
 108     @Override
 109     public Node leaveAccessNode(final AccessNode accessNode) {
 110         return setProgramPoint(accessNode);
 111     }
 112 
 113     @Override
 114     public Node leaveIndexNode(final IndexNode indexNode) {
 115         return setProgramPoint(indexNode);
 116     }
 117 
 118     @Override
 119     public Node leaveBinaryNode(final BinaryNode binaryNode) {
 120         return setProgramPoint(binaryNode);
 121     }
 122 
 123     @Override
 124     public Node leaveUnaryNode(final UnaryNode unaryNode) {
 125         return setProgramPoint(unaryNode);
 126     }
 127 }