soot.jimple.validation.ReturnStatementsValidator Maven / Gradle / Ivy

package soot.jimple.validation;

/*-
 * #%L
 * Soot - a J*va Optimization Framework
 * %%
 * Copyright (C) 1997 - 2018 Raja Vallée-Rai and others
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */

import java.util.List;

import soot.Body;
import soot.Unit;
import soot.jimple.GotoStmt;
import soot.jimple.RetStmt;
import soot.jimple.ReturnStmt;
import soot.jimple.ReturnVoidStmt;
import soot.jimple.ThrowStmt;
import soot.validation.BodyValidator;
import soot.validation.ValidationException;

public enum ReturnStatementsValidator implements BodyValidator {
  INSTANCE;

  public static ReturnStatementsValidator v() {
    return INSTANCE;
  }

  /**
   * Checks the following invariants on this Jimple body:
   * 
   * this-references may only occur in instance methods
   * 
this-references may only occur as the first statement in a method, if they occur at all
   * 
param-references must precede all statements that are not themselves param-references or this-references, if they
   * occur at all
   * 
   */
  @Override
  public void validate(Body body, List exceptions) {
    // Checks that this Jimple body actually contains a return statement
    for (Unit u : body.getUnits()) {
      if ((u instanceof ReturnStmt) || (u instanceof ReturnVoidStmt) || (u instanceof RetStmt) || (u instanceof ThrowStmt)) {
        return;
      }
    }

    // A method can have an infinite loop
    // and no return statement:
    //
    // public class Infinite {
    // public static void main(String[] args) {
    // int i = 0; while (true) {i += 1;} } }
    //
    // Only check that the execution cannot fall off the code.
    Unit last = body.getUnits().getLast();
    if (last instanceof GotoStmt || last instanceof ThrowStmt) {
      return;
    }

    exceptions.add(new ValidationException(body.getMethod(), "The method does not contain a return statement",
        "Body of method " + body.getMethod().getSignature() + " does not contain a return statement"));
  }

  @Override
  public boolean isBasicValidator() {
    return true;
  }
}