// Copyright (c) 2021, 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.ir.optimize.classinliner.analysis;

import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.ir.analysis.framework.intraprocedural.DataflowAnalysisResult.SuccessfulDataflowAnalysisResult;
import com.android.tools.r8.ir.analysis.framework.intraprocedural.IntraproceduralDataflowAnalysis;
import com.android.tools.r8.ir.code.IRCode;
import com.android.tools.r8.ir.optimize.classinliner.constraint.ClassInlinerMethodConstraint;
import com.android.tools.r8.ir.optimize.classinliner.constraint.ConditionalClassInlinerMethodConstraint;
import com.android.tools.r8.shaking.AppInfoWithLiveness;
import com.android.tools.r8.utils.Timing;

public class ClassInlinerMethodConstraintAnalysis {

  public static ClassInlinerMethodConstraint analyze(
      AppView<AppInfoWithLiveness> appView, ProgramMethod method, IRCode code, Timing timing) {
    if (method.getDefinition().isClassInitializer()
        || method.getDefinition().getNumberOfArguments() == 0) {
      return ClassInlinerMethodConstraint.alwaysFalse();
    }

    // Analyze code.
    IntraproceduralDataflowAnalysis<ParameterUsages> analysis =
        new IntraproceduralDataflowAnalysis<>(
            ParameterUsages.bottom(), code, new TransferFunction(appView, method, code));
    SuccessfulDataflowAnalysisResult<?, ParameterUsages> result =
        timing.time(
            "Data flow analysis",
            () -> analysis.run(code.entryBlock(), timing).asSuccessfulAnalysisResult());
    if (result == null) {
      return ClassInlinerMethodConstraint.alwaysFalse();
    }
    ParameterUsages usages = timing.time("Externalize", () -> result.join().externalize());
    if (usages.isBottom()) {
      return ClassInlinerMethodConstraint.alwaysTrue();
    }
    if (usages.isTop()) {
      return ClassInlinerMethodConstraint.alwaysFalse();
    }
    return new ConditionalClassInlinerMethodConstraint(usages);
  }
}