| /* |
| * 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.JDeclaredType; |
| import com.google.gwt.dev.jjs.ast.JMethod; |
| import com.google.gwt.dev.jjs.ast.JMethodCall; |
| import com.google.gwt.dev.jjs.ast.JModVisitor; |
| import com.google.gwt.dev.jjs.ast.JProgram; |
| import com.google.gwt.thirdparty.guava.common.collect.ImmutableList; |
| |
| /** |
| * Java8 default methods are implemented by creating a forwarding (with static dispatch) the |
| * implementing method on implementing classes to an the default method in an interface (which is |
| * modeled as an instance method). JavaScript lacks the notion of interfaces and GWT consequently |
| * does not generate prototypes nor instance method for interfaces. Due to that fact this pass |
| * devirtualizes the default methods into static interface methods. |
| * <p> |
| * This devirtualization could also be handled by Devirtualizer. |
| */ |
| public class DevirtualizeDefaultMethodForwarding { |
| |
| public static void exec(final JProgram program) { |
| final MakeCallsStatic.CreateStaticImplsVisitor staticImplCreator = |
| new MakeCallsStatic.CreateStaticImplsVisitor(program); |
| // 1. create the static implementations. Also process reference only types so that the mapping |
| // between a method and its devirtualized version is consistent during incremental compilation. |
| // NOTE: the process needs to be done in two steps because the creation of static implementation |
| // might introduce call sites in types that were already processed and hence would not be |
| // rewritten (bug #9453). |
| for (JDeclaredType type : program.getDeclaredTypes()) { |
| // Iterate over the methods using a copy to avoid ConcurrentModificationException as the |
| // the devirualized method is added to the type following the current method. |
| for (JMethod method : ImmutableList.copyOf(type.getMethods())) { |
| if (method.isDefaultMethod()) { |
| staticImplCreator.getOrCreateStaticImpl(program, method); |
| } |
| } |
| } |
| |
| // 2. Devirtualize (static dispatch) calls to the default method. |
| new JModVisitor() { |
| @Override |
| public void endVisit(JMethodCall x, Context ctx) { |
| JMethod targetMethod = x.getTarget(); |
| if (targetMethod.isDefaultMethod() && x.isStaticDispatchOnly()) { |
| assert x.getInstance() != null; |
| |
| JMethod staticMethod = program.getStaticImpl(targetMethod); |
| assert staticMethod != null; |
| // Need to devirtualize because instance methods are not emitted for interfaces. |
| JMethodCall callStaticMethod = new JMethodCall(x.getSourceInfo(), null, staticMethod); |
| // Add the qualifier as a first parameter (usually 'this', unless the enclosing method was |
| // devirtualized first). |
| callStaticMethod.addArg(x.getInstance()); |
| callStaticMethod.addArgs(x.getArgs()); |
| ctx.replaceMe(callStaticMethod); |
| } |
| } |
| }.accept(program); |
| } |
| } |