src/main/java/com/android/tools/r8/cf/code/CfIinc.java

// Copyright (c) 2018, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8.cf.code;

import com.android.tools.r8.cf.CfPrinter;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.CfCode;
import com.android.tools.r8.graph.CfCompareHelper;
import com.android.tools.r8.graph.DexItemFactory;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.GraphLens;
import com.android.tools.r8.graph.InitClassLens;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.ir.code.NumericType;
import com.android.tools.r8.ir.code.ValueType;
import com.android.tools.r8.ir.conversion.CfSourceCode;
import com.android.tools.r8.ir.conversion.CfState;
import com.android.tools.r8.ir.conversion.IRBuilder;
import com.android.tools.r8.ir.conversion.LensCodeRewriterUtils;
import com.android.tools.r8.ir.optimize.Inliner.ConstraintWithTarget;
import com.android.tools.r8.ir.optimize.InliningConstraints;
import com.android.tools.r8.naming.NamingLens;
import com.android.tools.r8.optimize.interfaces.analysis.CfFrameState;
import com.android.tools.r8.utils.FunctionUtils;
import com.android.tools.r8.utils.structural.CompareToVisitor;
import com.android.tools.r8.utils.structural.StructuralSpecification;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public class CfIinc extends CfInstruction {

  private final int var;
  private final int increment;

  private static void specify(StructuralSpecification<CfIinc, ?> spec) {
    spec.withInt(CfIinc::getLocalIndex).withInt(CfIinc::getIncrement);
  }

  public CfIinc(int var, int increment) {
    this.var = var;
    this.increment = increment;
  }

  @Override
  public int getCompareToId() {
    return Opcodes.IINC;
  }

  @Override
  public int internalAcceptCompareTo(
      CfInstruction other, CompareToVisitor visitor, CfCompareHelper helper) {
    return visitor.visit(this, (CfIinc) other, CfIinc::specify);
  }

  @Override
  public void write(
      AppView<?> appView,
      ProgramMethod context,
      DexItemFactory dexItemFactory,
      GraphLens graphLens,
      InitClassLens initClassLens,
      NamingLens namingLens,
      LensCodeRewriterUtils rewriter,
      MethodVisitor visitor) {
    visitor.visitIincInsn(var, increment);
  }

  @Override
  public int bytecodeSizeUpperBound() {
    // iinc or wide iinc
    return var < 256 && increment < 256 ? 3 : 6;
  }

  @Override
  public void print(CfPrinter printer) {
    printer.print(this);
  }

  public int getLocalIndex() {
    return var;
  }

  public int getIncrement() {
    return increment;
  }

  @Override
  public void buildIR(IRBuilder builder, CfState state, CfSourceCode code) {
    int local = state.read(var).register;
    builder.addAddLiteral(NumericType.INT, local, local, increment);
  }

  @Override
  public ConstraintWithTarget inliningConstraint(
      InliningConstraints inliningConstraints, CfCode code, ProgramMethod context) {
    return ConstraintWithTarget.ALWAYS;
  }

  @Override
  public void evaluate(
      CfFrameVerificationHelper frameBuilder,
      DexMethod context,
      AppView<?> appView,
      DexItemFactory dexItemFactory) {
    frameBuilder.readLocal(var, dexItemFactory.intType);
  }

  @Override
  public CfFrameState evaluate(
      CfFrameState frame,
      ProgramMethod context,
      AppView<?> appView,
      DexItemFactory dexItemFactory) {
    return frame.readLocal(appView, getLocalIndex(), ValueType.INT, FunctionUtils::getFirst);
  }
}