/*
* 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.copy;
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.ast.JVariableRef;
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.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.copy.CopyAssumption.Updater;
/**
* Flow function for CopyAnalysis.
*/
public class CopyFlowFunction implements
FlowFunction<CfgNode<?>, CfgEdge, Cfg, CopyAssumption> {
@Override
public void interpret(CfgNode<?> node,
Cfg g, AssumptionMap<CfgEdge, CopyAssumption> assumptionMap) {
CopyAssumption in = AssumptionUtil.join(g.getInEdges(node), assumptionMap);
final Updater result = new Updater(in);
node.accept(new CfgVisitor() {
@Override
public void visitReadWriteNode(CfgReadWriteNode node) {
JVariable targetVariable = node.getTargetVariable();
if (isSupportedVar(targetVariable)) {
result.kill(targetVariable);
}
}
@Override
public void visitWriteNode(CfgWriteNode node) {
JVariable targetVariable = node.getTargetVariable();
if (!isSupportedVar(targetVariable)) {
return;
}
if (!(node.getValue() instanceof JVariableRef)) {
result.kill(targetVariable);
return;
}
JVariable original = ((JVariableRef) node.getValue()).getTarget();
original = result.getMostOriginal(original);
if (original != targetVariable) {
result.kill(targetVariable);
if (isSupportedVar(original) &&
original.getType() == targetVariable.getType()) {
result.addCopy(original, targetVariable);
}
} else {
// We don't have to kill any assumptions after i = i assignment.
}
}
private boolean isSupportedVar(JVariable targetVariable) {
return targetVariable instanceof JParameter ||
targetVariable instanceof JLocal;
}
});
AssumptionUtil.setAssumptions(g.getOutEdges(node), result.unwrap(), assumptionMap);
}
}