| /* |
| * 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.constants; |
| |
| import com.google.gwt.dev.jjs.ast.JBooleanLiteral; |
| import com.google.gwt.dev.jjs.ast.JExpression; |
| import com.google.gwt.dev.jjs.ast.JValueLiteral; |
| 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.TransformationFunction; |
| import com.google.gwt.dev.jjs.impl.gflow.cfg.Cfg; |
| import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgConditionalNode; |
| 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.CfgTransformer; |
| import com.google.gwt.dev.jjs.impl.gflow.cfg.CfgVisitor; |
| import com.google.gwt.dev.util.Preconditions; |
| |
| /** |
| * Transformation function for ConstantsAnalysis. Checks if current node can |
| * be simplified using assumptions |
| */ |
| public class ConstantsTransformationFunction implements |
| TransformationFunction<CfgNode<?>, CfgEdge, CfgTransformer, Cfg, |
| ConstantsAssumption> { |
| private final class MyTransformationVisitor extends CfgVisitor { |
| private final ConstantsAssumption assumption; |
| private final Cfg graph; |
| private Transformation<CfgTransformer, Cfg> result = null; |
| |
| private MyTransformationVisitor(Cfg graph, ConstantsAssumption assumption) { |
| this.graph = graph; |
| this.assumption = assumption; |
| } |
| |
| @Override |
| public void visitConditionalNode(final CfgConditionalNode<?> node) { |
| JExpression condition = node.getCondition(); |
| if (condition instanceof JValueLiteral) { |
| return; |
| } |
| |
| Preconditions.checkNotNull(condition, |
| "Null condition in %s: %s", node, node.getJNode()); |
| JValueLiteral evaluatedCondition = |
| ExpressionEvaluator.evaluate(condition, assumption); |
| |
| if (evaluatedCondition == null || |
| !(evaluatedCondition instanceof JBooleanLiteral)) { |
| super.visitConditionalNode(node); |
| return; |
| } |
| |
| final boolean b = ((JBooleanLiteral) evaluatedCondition).getValue(); |
| result = new ConstantConditionTransformation(graph, b, node); |
| } |
| |
| @Override |
| public void visitReadNode(CfgReadNode node) { |
| if (assumption.hasAssumption(node.getTarget())) { |
| result = new FoldConstantsTransformation(assumption, node, graph); |
| } |
| } |
| } |
| |
| public Transformation<CfgTransformer, Cfg> transform( |
| final CfgNode<?> node, final Cfg graph, |
| final AssumptionMap<CfgEdge, ConstantsAssumption> assumptionMap) { |
| ConstantsAssumption assumption = AssumptionUtil.join( |
| graph.getInEdges(node), assumptionMap); |
| if (assumption == null) { |
| return null; |
| } |
| |
| MyTransformationVisitor visitor = new MyTransformationVisitor(graph, |
| assumption); |
| node.accept(visitor); |
| return visitor.result; |
| } |
| } |