예제 #1
0
 private void removeRedundantCopies(
     Program program, List<MutableGraphNode> interferenceGraph, DisjointSet congruenceClasses) {
   for (int i = 0; i < program.basicBlockCount(); ++i) {
     BasicBlock block = program.basicBlockAt(i);
     for (int j = 0; j < block.getInstructions().size(); ++j) {
       Instruction insn = block.getInstructions().get(j);
       if (!(insn instanceof AssignInstruction)) {
         continue;
       }
       AssignInstruction assignment = (AssignInstruction) insn;
       boolean interfere = false;
       int copyClass = congruenceClasses.find(assignment.getReceiver().getIndex());
       int origClass = congruenceClasses.find(assignment.getAssignee().getIndex());
       for (MutableGraphEdge edge : interferenceGraph.get(origClass).getEdges()) {
         if (edge.getFirst() == edge.getSecond()) {
           continue;
         }
         int neighbour = congruenceClasses.find(edge.getSecond().getTag());
         if (neighbour == copyClass || neighbour == origClass) {
           interfere = true;
           break;
         }
       }
       if (!interfere) {
         int newClass = congruenceClasses.union(copyClass, origClass);
         block.getInstructions().set(j, new EmptyInstruction());
         if (newClass == interferenceGraph.size()) {
           MutableGraphNode newNode = new MutableGraphNode(interferenceGraph.size());
           interferenceGraph.add(newNode);
         }
         for (MutableGraphEdge edge :
             interferenceGraph.get(origClass).getEdges().toArray(new MutableGraphEdge[0])) {
           if (edge.getFirst() == interferenceGraph.get(origClass)) {
             edge.setFirst(interferenceGraph.get(newClass));
           }
           if (edge.getSecond() == interferenceGraph.get(origClass)) {
             edge.setSecond(interferenceGraph.get(newClass));
           }
         }
         for (MutableGraphEdge edge :
             interferenceGraph.get(copyClass).getEdges().toArray(new MutableGraphEdge[0])) {
           if (edge.getFirst() == interferenceGraph.get(copyClass)) {
             edge.setFirst(interferenceGraph.get(newClass));
           }
           if (edge.getSecond() == interferenceGraph.get(copyClass)) {
             edge.setSecond(interferenceGraph.get(newClass));
           }
         }
         interferenceGraph.set(copyClass, interferenceGraph.get(newClass));
         interferenceGraph.set(origClass, interferenceGraph.get(newClass));
       }
     }
   }
 }
예제 #2
0
 private static void joinClassNodes(List<MutableGraphNode> graph, DisjointSet classes) {
   int sz = graph.size();
   for (int i = 0; i < sz; ++i) {
     int cls = classes.find(i);
     while (cls >= graph.size()) {
       graph.add(new MutableGraphNode(graph.size()));
     }
     if (cls != i) {
       for (MutableGraphEdge edge : graph.get(i).getEdges().toArray(new MutableGraphEdge[0])) {
         if (edge.getFirst() == graph.get(i)) {
           edge.setFirst(graph.get(cls));
         }
         if (edge.getSecond() == graph.get(i)) {
           edge.setSecond(graph.get(cls));
         }
       }
       graph.set(i, graph.get(cls));
     }
   }
 }