com.android.dx.dex.code.OddSpacer Maven / Gradle / Ivy
/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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.android.dx.dex.code;
import com.android.dx.io.Opcodes;
import com.android.dx.rop.code.RegisterSpecList;
import com.android.dx.rop.code.SourcePosition;
import com.android.dx.util.AnnotatedOutput;
/**
* Pseudo-instruction which either turns into a {@code nop} or
* nothingness, in order to make the subsequent instruction have an
* even address. This is used to align (subsequent) instructions that
* require it.
*/
public final class OddSpacer extends VariableSizeInsn {
/**
* Constructs an instance. The output address of this instance is initially
* unknown ({@code -1}).
*
* @param position {@code non-null;} source position
*/
public OddSpacer(SourcePosition position) {
super(position, RegisterSpecList.EMPTY);
}
/** {@inheritDoc} */
@Override
public int codeSize() {
return (getAddress() & 1);
}
/** {@inheritDoc} */
@Override
public void writeTo(AnnotatedOutput out) {
if (codeSize() != 0) {
out.writeShort(InsnFormat.codeUnit(Opcodes.NOP, 0));
}
}
/** {@inheritDoc} */
@Override
public DalvInsn withRegisters(RegisterSpecList registers) {
return new OddSpacer(getPosition());
}
/** {@inheritDoc} */
@Override
protected String argString() {
return null;
}
/** {@inheritDoc} */
@Override
protected String listingString0(boolean noteIndices) {
if (codeSize() == 0) {
return null;
}
return "nop // spacer";
}
}