/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Common Public License (CPL);
* You may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.opensource.org/licenses/cpl1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.jikesrvm.compilers.opt;
import java.util.HashMap;
import org.jikesrvm.compilers.opt.ir.OPT_IR;
import org.jikesrvm.compilers.opt.ir.OPT_Register;
/**
* An object that returns an estimate of the relative cost of spilling a
* symbolic register.
*/
abstract class OPT_SpillCostEstimator {
private final HashMap<OPT_Register, Double> map = new HashMap<OPT_Register, Double>();
/**
* Return a number that represents an estimate of the relative cost of
* spilling register r.
*/
double getCost(OPT_Register r) {
Double d = map.get(r);
if (d == null) {
return 0;
} else {
return d;
}
}
/**
* Calculate the estimated cost for each register.
*/
abstract void calculate(OPT_IR ir);
/**
* Update the cost for a particular register.
*/
protected void update(OPT_Register r, double delta) {
double c = getCost(r);
c += delta;
map.put(r, c);
}
}