1 /*
   2  * Copyright (c) 2012, 2017, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.loop;
  24 
  25 import java.util.ArrayList;
  26 import java.util.Collection;
  27 import java.util.LinkedList;
  28 import java.util.List;
  29 
  30 import org.graalvm.compiler.core.common.cfg.Loop;
  31 import org.graalvm.compiler.debug.Debug;
  32 import org.graalvm.compiler.debug.Debug.Scope;
  33 import org.graalvm.compiler.nodes.LoopBeginNode;
  34 import org.graalvm.compiler.nodes.StructuredGraph;
  35 import org.graalvm.compiler.nodes.ValueNode;
  36 import org.graalvm.compiler.nodes.cfg.Block;
  37 import org.graalvm.compiler.nodes.cfg.ControlFlowGraph;
  38 import org.graalvm.util.Equivalence;
  39 import org.graalvm.util.EconomicMap;
  40 import org.graalvm.util.EconomicSet;
  41 
  42 public class LoopsData {
  43     private final EconomicMap<LoopBeginNode, LoopEx> loopBeginToEx = EconomicMap.create(Equivalence.IDENTITY);
  44     private final ControlFlowGraph cfg;
  45     private final List<LoopEx> loops;
  46 
  47     @SuppressWarnings("try")
  48     public LoopsData(final StructuredGraph graph) {
  49         try (Scope s = Debug.scope("ControlFlowGraph")) {
  50             cfg = ControlFlowGraph.compute(graph, true, true, true, true);
  51         } catch (Throwable e) {
  52             throw Debug.handle(e);
  53         }
  54         assert checkLoopOrder(cfg.getLoops());
  55         loops = new ArrayList<>(cfg.getLoops().size());
  56         for (Loop<Block> loop : cfg.getLoops()) {
  57             LoopEx ex = new LoopEx(loop, this);
  58             loops.add(ex);
  59             loopBeginToEx.put(ex.loopBegin(), ex);
  60         }
  61     }
  62 
  63     /**
  64      * Checks that loops are ordered such that outer loops appear first.
  65      */
  66     private static boolean checkLoopOrder(Iterable<Loop<Block>> loops) {
  67         EconomicSet<Loop<Block>> seen = EconomicSet.create(Equivalence.IDENTITY);
  68         for (Loop<Block> loop : loops) {
  69             if (loop.getParent() != null && !seen.contains(loop.getParent())) {
  70                 return false;
  71             }
  72             seen.add(loop);
  73         }
  74         return true;
  75     }
  76 
  77     public LoopEx loop(Loop<Block> loop) {
  78         return loopBeginToEx.get((LoopBeginNode) loop.getHeader().getBeginNode());
  79     }
  80 
  81     public LoopEx loop(LoopBeginNode loopBegin) {
  82         return loopBeginToEx.get(loopBegin);
  83     }
  84 
  85     public List<LoopEx> loops() {
  86         return loops;
  87     }
  88 
  89     public List<LoopEx> outerFirst() {
  90         return loops;
  91     }
  92 
  93     public Collection<LoopEx> countedLoops() {
  94         List<LoopEx> counted = new LinkedList<>();
  95         for (LoopEx loop : loops()) {
  96             if (loop.isCounted()) {
  97                 counted.add(loop);
  98             }
  99         }
 100         return counted;
 101     }
 102 
 103     public void detectedCountedLoops() {
 104         for (LoopEx loop : loops()) {
 105             loop.detectCounted();
 106         }
 107     }
 108 
 109     public ControlFlowGraph getCFG() {
 110         return cfg;
 111     }
 112 
 113     public InductionVariable getInductionVariable(ValueNode value) {
 114         InductionVariable match = null;
 115         for (LoopEx loop : loops()) {
 116             InductionVariable iv = loop.getInductionVariables().get(value);
 117             if (iv != null) {
 118                 if (match != null) {
 119                     return null;
 120                 }
 121                 match = iv;
 122             }
 123         }
 124         return match;
 125     }
 126 
 127     /**
 128      * Deletes any nodes created within the scope of this object that have no usages.
 129      */
 130     public void deleteUnusedNodes() {
 131         for (LoopEx loop : loops()) {
 132             loop.deleteUnusedNodes();
 133         }
 134     }
 135 }