/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.jjs.impl.gflow.liveness;
import com.google.gwt.dev.jjs.ast.JLocal;
import com.google.gwt.dev.jjs.ast.JParameter;
import com.google.gwt.dev.jjs.ast.JVariable;
import com.google.gwt.dev.jjs.impl.gflow.AssumptionMap;
import com.google.gwt.dev.jjs.impl.gflow.AssumptionUtil;
import com.google.gwt.dev.jjs.impl.gflow.FlowFunction;
import com.google.gwt.dev.jjs.impl.gflow.cfg.Cfg;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgEdge;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgNode;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgReadNode;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgReadWriteNode;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgVisitor;
import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgWriteNode;
import com.google.gwt.dev.jjs.impl.gflow.liveness.LivenessAssumption.Updater;
/**
* Flow function for Liveness Analysis.
*/
public class LivenessFlowFunction implements FlowFunction<CfgNode<?>, CfgEdge,
Cfg, LivenessAssumption> {
@Override
public void interpret(CfgNode<?> node, Cfg g,
AssumptionMap<CfgEdge, LivenessAssumption> assumptionMap) {
final Updater result = new Updater(
AssumptionUtil.join(g.getOutEdges(node), assumptionMap));
node.accept(new CfgVisitor() {
@Override
public void visitReadNode(CfgReadNode node) {
JVariable target = node.getTarget();
if (target instanceof JLocal || target instanceof JParameter) {
result.use(target);
}
}
@Override
public void visitReadWriteNode(CfgReadWriteNode node) {
JVariable target = node.getTargetVariable();
if (target instanceof JLocal || target instanceof JParameter) {
result.use(target);
}
}
@Override
public void visitWriteNode(CfgWriteNode node) {
JVariable target = node.getTargetVariable();
if (target instanceof JLocal || target instanceof JParameter) {
result.kill(target);
}
}
});
AssumptionUtil.setAssumptions(g.getInEdges(node), result.unwrap(), assumptionMap);
}
}