001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.compilers.opt;
014    
015    import java.util.Enumeration;
016    
017    import org.jikesrvm.compilers.opt.driver.CompilerPhase;
018    import org.jikesrvm.compilers.opt.ir.Move;
019    import org.jikesrvm.compilers.opt.ir.IR;
020    import org.jikesrvm.compilers.opt.ir.IRTools;
021    import org.jikesrvm.compilers.opt.ir.Instruction;
022    import org.jikesrvm.compilers.opt.ir.Operator;
023    import static org.jikesrvm.compilers.opt.ir.Operators.SPLIT;
024    import org.jikesrvm.compilers.opt.ir.Unary;
025    import org.jikesrvm.compilers.opt.ir.operand.Operand;
026    import org.jikesrvm.compilers.opt.ir.operand.RegisterOperand;
027    
028    /**
029     * Change SPLIT operations inserting for live range splitting into Moves.
030     */
031    public final class MutateSplits extends CompilerPhase {
032    
033      /**
034       * Return this instance of this phase. This phase contains no
035       * per-compilation instance fields.
036       * @param ir not used
037       * @return this
038       */
039      @Override
040      public CompilerPhase newExecution(IR ir) {
041        return this;
042      }
043    
044      @Override
045      public boolean shouldPerform(OptOptions options) {
046        return options.SSA_LIVE_RANGE_SPLITTING;
047      }
048    
049      @Override
050      public String getName() {
051        return "Mutate Splits";
052      }
053    
054      /**
055       * The main entrypoint for this pass.
056       */
057      @Override
058      public void perform(IR ir) {
059        for (Enumeration<Instruction> e = ir.forwardInstrEnumerator(); e.hasMoreElements();) {
060          Instruction s = e.nextElement();
061          if (s.operator == SPLIT) {
062            RegisterOperand lhs = Unary.getResult(s);
063            Operator mv = IRTools.getMoveOp(lhs.getType());
064            Operand rhs = Unary.getVal(s);
065            Move.mutate(s, mv, lhs, rhs);
066          }
067        }
068      }
069    }