| // Copyright 2016 The Bazel Authors. All rights reserved. |
| // |
| // 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.devtools.build.android.desugar; |
| |
| import com.google.common.collect.ImmutableSet; |
| import org.objectweb.asm.ClassVisitor; |
| import org.objectweb.asm.Handle; |
| import org.objectweb.asm.MethodVisitor; |
| import org.objectweb.asm.Opcodes; |
| |
| /** |
| * Class visitor to collect all the lambda methods that are used in invokedynamic instructions. |
| * |
| * <p>Note that this class only collects lambda methods. If the invokedynamic is used for other |
| * purposes, the methods used in the instruction are NOT collected. |
| */ |
| class InvokeDynamicLambdaMethodCollector extends ClassVisitor { |
| |
| private final ImmutableSet.Builder<MethodInfo> lambdaMethodsUsedInInvokeDynamic = |
| ImmutableSet.builder(); |
| private boolean needOuterClassRewrite = false; |
| |
| public InvokeDynamicLambdaMethodCollector() { |
| super(Opcodes.ASM7); |
| } |
| |
| /** |
| * Returns whether the visited class is declared in the scope of a lambda. In that case |
| * {@link LambdaDesugaring} will want to rewrite the EnclosingMethod attribute of the class. |
| */ |
| public boolean needOuterClassRewrite() { |
| return needOuterClassRewrite; |
| } |
| |
| /** Returns methods referenced in invokedynamic instructions that use LambdaMetafactory. */ |
| public ImmutableSet<MethodInfo> getLambdaMethodsUsedInInvokeDynamics() { |
| return lambdaMethodsUsedInInvokeDynamic.build(); |
| } |
| |
| @Override |
| public MethodVisitor visitMethod( |
| int access, String name, String desc, String signature, String[] exceptions) { |
| MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions); |
| return new LambdaMethodCollector(mv); |
| } |
| |
| @Override |
| public void visitOuterClass(String owner, String name, String desc) { |
| needOuterClassRewrite = needOuterClassRewrite || (name != null && name.startsWith("lambda$")); |
| super.visitOuterClass(owner, name, desc); |
| } |
| |
| private class LambdaMethodCollector extends MethodVisitor { |
| |
| public LambdaMethodCollector(MethodVisitor dest) { |
| super(Opcodes.ASM7, dest); |
| } |
| |
| @Override |
| public void visitInvokeDynamicInsn(String name, String desc, Handle bsm, Object... bsmArgs) { |
| if (!"java/lang/invoke/LambdaMetafactory".equals(bsm.getOwner())) { |
| // Not an invokedynamic for a lambda expression |
| return; |
| } |
| Handle handle = (Handle) bsmArgs[1]; |
| lambdaMethodsUsedInInvokeDynamic.add( |
| MethodInfo.create(handle.getOwner(), handle.getName(), handle.getDesc())); |
| super.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs); |
| } |
| } |
| } |