| /* |
| * 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.IntegratedFlowFunction; |
| import com.google.gwt.dev.jjs.impl.gflow.TransformationFunction.Transformation; |
| 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.CfgTransformer; |
| import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgWriteNode; |
| |
| /** |
| * |
| */ |
| public class LivenessIntegratedFlowFunction implements |
| IntegratedFlowFunction<CfgNode<?>, CfgEdge, CfgTransformer, Cfg, |
| LivenessAssumption> { |
| private final LivenessFlowFunction flowFunction = new LivenessFlowFunction(); |
| |
| public Transformation<CfgTransformer, Cfg> |
| interpretOrReplace(CfgNode<?> node, Cfg graph, |
| AssumptionMap<CfgEdge, LivenessAssumption> assumptionMap) { |
| LivenessAssumption assumptions = AssumptionUtil.join( |
| graph.getOutEdges(node), assumptionMap); |
| |
| if (node instanceof CfgWriteNode) { |
| CfgWriteNode write = (CfgWriteNode) node; |
| JVariable variable = write.getTargetVariable(); |
| if ((variable instanceof JLocal || variable instanceof JParameter) && |
| !isLive(assumptions, variable) && write.getValue() != null) { |
| return new LivenessTransformation(graph, write); |
| } |
| } |
| |
| flowFunction.interpret(node, graph, assumptionMap); |
| return null; |
| } |
| |
| private boolean isLive(LivenessAssumption assumptions, JVariable variable) { |
| return assumptions != null && assumptions.isLive(variable); |
| } |
| } |