| /* |
| * Copyright 2014 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; |
| |
| import com.google.gwt.dev.jjs.ast.Context; |
| import com.google.gwt.dev.jjs.ast.JCastOperation; |
| import com.google.gwt.dev.jjs.ast.JExpression; |
| import com.google.gwt.dev.jjs.ast.JField; |
| import com.google.gwt.dev.jjs.ast.JFieldRef; |
| import com.google.gwt.dev.jjs.ast.JModVisitor; |
| import com.google.gwt.dev.jjs.ast.JProgram; |
| import com.google.gwt.dev.jjs.ast.JType; |
| import com.google.gwt.thirdparty.guava.common.collect.Maps; |
| |
| import java.util.Map; |
| |
| /** |
| * Replaces compile time constants by their values. |
| * <p> |
| * This pass is necessary, even in unoptimized compiles, to allow forward references to compile |
| * time values in bootstrap code. |
| **/ |
| public class CompileTimeConstantsReplacer { |
| private static class CompileTimeConstantsReplacingVisitor extends JModVisitor { |
| |
| private final Map<JField, JExpression> resolveValuesByField = Maps.newIdentityHashMap(); |
| private final JProgram program; |
| |
| @Override |
| public void endVisit(JFieldRef x, Context ctx) { |
| JField field = x.getField(); |
| if (field.isCompileTimeConstant() && !ctx.isLvalue()) { |
| ctx.replaceMe(resolveFieldValue(field)); |
| } |
| } |
| |
| private JExpression resolveFieldValue(JField field) { |
| JExpression value = resolveValuesByField.get(field); |
| if (value != null) { |
| return new CloneExpressionVisitor().cloneExpression(value); |
| } |
| // TODO(rluble): Simplify the expression to a literal here after refactoring Simplifier. |
| // The initializer is guaranteed to be constant but it may be a non literal expression, so |
| // clone it and recursively remove field references, and finally cache the results. |
| value = accept(new CloneExpressionVisitor().cloneExpression(field.getInitializer())); |
| JType fieldType = field.getType().getUnderlyingType(); |
| assert fieldType.isPrimitiveType() || fieldType == program.getTypeJavaLangString() |
| : fieldType.getName() + " is not a primitive nor String"; |
| if (fieldType != value.getType()) { |
| value = new JCastOperation(value.getSourceInfo(), fieldType, value); |
| } |
| resolveValuesByField.put(field, value); |
| return value; |
| } |
| |
| private CompileTimeConstantsReplacingVisitor(JProgram program) { |
| this.program = program; |
| } |
| } |
| public static void exec(JProgram program) { |
| new CompileTimeConstantsReplacingVisitor(program).accept(program); |
| } |
| } |