| // 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 static org.objectweb.asm.Opcodes.ASM5; |
| import static org.objectweb.asm.Opcodes.DUP; |
| import static org.objectweb.asm.Opcodes.INVOKESTATIC; |
| import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL; |
| import static org.objectweb.asm.Opcodes.POP; |
| |
| import org.objectweb.asm.ClassVisitor; |
| import org.objectweb.asm.MethodVisitor; |
| |
| /** |
| * This class desugars any call to Objects.requireNonNull(Object o), Objects.requireNonNull(Object |
| * o, String msg), and Objects.requireNonNull(Object o, Supplier msg), by replacing the call with |
| * o.getClass(). Note that currently we discard the message, as inlining the message involves |
| * changes to the control flow graph, which further requires re-computation of the stack map frames. |
| */ |
| public class ObjectsRequireNonNullMethodInliner extends ClassVisitor { |
| |
| public ObjectsRequireNonNullMethodInliner(ClassVisitor cv) { |
| super(ASM5, cv); |
| } |
| |
| @Override |
| public MethodVisitor visitMethod( |
| int access, String name, String desc, String signature, String[] exceptions) { |
| MethodVisitor visitor = super.cv.visitMethod(access, name, desc, signature, exceptions); |
| return visitor == null ? visitor : new ObjectsMethodInlinerMethodVisitor(visitor); |
| } |
| |
| private static class ObjectsMethodInlinerMethodVisitor extends MethodVisitor { |
| |
| public ObjectsMethodInlinerMethodVisitor(MethodVisitor mv) { |
| super(ASM5, mv); |
| } |
| |
| @Override |
| public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) { |
| if (opcode != INVOKESTATIC |
| || !owner.equals("java/util/Objects") |
| || !name.equals("requireNonNull") |
| || !desc.equals("(Ljava/lang/Object;)Ljava/lang/Object;")) { |
| super.visitMethodInsn(opcode, owner, name, desc, itf); |
| return; |
| } |
| |
| // a call to Objects.requireNonNull(Object o) |
| // duplicate the first argument 'o', as this method returns 'o'. |
| super.visitInsn(DUP); |
| super.visitMethodInsn( |
| INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false); |
| super.visitInsn(POP); |
| } |
| } |
| } |