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package soot.dava.toolkits.base.AST.structuredAnalysis;

/*-
 * #%L
 * Soot - a J*va Optimization Framework
 * %%
 * Copyright (C) 2005 Nomair A. Naeem
 * %%
 * 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.ArrayList;
import java.util.Iterator;
import java.util.List;

import soot.Local;
import soot.Value;
import soot.dava.internal.AST.ASTDoWhileNode;
import soot.dava.internal.AST.ASTForLoopNode;
import soot.dava.internal.AST.ASTNode;
import soot.dava.internal.AST.ASTUnaryBinaryCondition;
import soot.dava.internal.AST.ASTUnconditionalLoopNode;
import soot.dava.internal.AST.ASTWhileNode;
import soot.dava.toolkits.base.AST.traversals.AllDefinitionsFinder;
import soot.jimple.DefinitionStmt;
import soot.jimple.Stmt;

//import soot.dava.internal.javaRep.*;
//import soot.dava.internal.SET.*;

/**
 * CHANGE LOG: * November 21st Added support for implicit breaks and continues Tested code for reaching defs within
 * switch/try/if/while/for
 *
 * * November 22nd Refactored code to make structure flow analysis framework handle breaks and returns.
 *
 * * November 24th newInitialFlow ERROR............initialFlow should be the set of all defs........since there needs to
 * exist SOME path
 */

/*
 * Reaching Defs Step 1: Set of definitions (a definition is a Stmt within a StatementSequenceNode) Step 2: A definition d: x
 * = ... reaches a point p in the program if there exists a path from p such that there is no other definition of x between d
 * and p. Step 3: Forward Analysis Step 4: Union Step 5: d: x = expr kill = { all existing defs of x}
 *
 * gen = (d)
 *
 * Step 6: newInitialFlow: No definitions reach (safe) (Catch bodies) //November 24th.........changing above to be the
 * universal set of all definitions
 *
 *
 * out(start) = {} since there has been no definition so far
 *
 * out(Si) not needed for structured flow analysis
 */

public class ReachingDefs extends StructuredAnalysis {
  Object toAnalyze;

  public ReachingDefs(Object analyze) {
    super();
    toAnalyze = analyze;
    process(analyze, new DavaFlowSet());
  }

  @Override
  public DavaFlowSet emptyFlowSet() {
    return new DavaFlowSet();
  }

  /*
   * Initial flow into catch statements is empty meaning no definition reaches
   */
  @Override
  public DavaFlowSet newInitialFlow() {
    DavaFlowSet initial = new DavaFlowSet();
    // find all definitions in the program
    AllDefinitionsFinder defFinder = new AllDefinitionsFinder();
    ((ASTNode) toAnalyze).apply(defFinder);
    List allDefs = defFinder.getAllDefs();
    // all defs is the list of all augmented stmts which contains
    // DefinitionStmts
    for (DefinitionStmt def : allDefs) {
      initial.add(def);
    }

    // initial is not the universal set of all definitions
    return initial;
  }

  /*
   * Using union
   */
  public void setMergeType() {
    MERGETYPE = UNION;
  }

  @Override
  public DavaFlowSet cloneFlowSet(DavaFlowSet flowSet) {
    return flowSet.clone();
  }

  /*
   * In the case of reachingDefs the evaluation of a condition has no effect on the reachingDefs
   */
  @Override
  public DavaFlowSet processUnaryBinaryCondition(ASTUnaryBinaryCondition cond, DavaFlowSet inSet) {
    return inSet;
  }

  /*
   * In the case of reachingDefs the use of a local has no effect on reachingDefs
   */
  @Override
  public DavaFlowSet processSynchronizedLocal(Local local, DavaFlowSet inSet) {
    return inSet;
  }

  /*
   * In the case of reachingDefs a value has no effect on reachingDefs
   */
  @Override
  public DavaFlowSet processSwitchKey(Value key, DavaFlowSet inSet) {
    return inSet;
  }

  /*
   * This method internally invoked by the process method decides which Statement specialized method to call
   */
  @Override
  public DavaFlowSet processStatement(Stmt s, DavaFlowSet inSet) {
    /*
     * If this path will not be taken return no path straightaway
     */
    if (inSet == NOPATH) {
      return inSet;
    }

    if (s instanceof DefinitionStmt) {
      DavaFlowSet toReturn = cloneFlowSet(inSet);
      // d:x = expr
      // gen is x
      // kill is all previous defs of x

      Value leftOp = ((DefinitionStmt) s).getLeftOp();

      if (leftOp instanceof Local) {
        // KILL any reaching defs of leftOp
        kill(toReturn, (Local) leftOp);
        // GEN
        gen(toReturn, (DefinitionStmt) s);
        return toReturn;
      } // leftop is a local
    }
    return inSet;
  }

  public void gen(DavaFlowSet in, DefinitionStmt s) {
    // System.out.println("Adding Definition Stmt: "+s);
    in.add(s);
  }

  public void kill(DavaFlowSet in, Local redefined) {
    String redefinedLocalName = redefined.getName();

    // kill any previous localpairs which have the redefined Local in the
    // left i.e. previous definitions
    for (Iterator listIt = in.iterator(); listIt.hasNext();) {
      DefinitionStmt tempStmt = (DefinitionStmt) listIt.next();
      Value leftOp = tempStmt.getLeftOp();
      if (leftOp instanceof Local) {
        String storedLocalName = ((Local) leftOp).getName();
        if (redefinedLocalName.compareTo(storedLocalName) == 0) {
          // need to kill this from the list
          // System.out.println("Killing "+tempStmt);
          listIt.remove();
        }
      }
    }
  }

  public List getReachingDefs(Local local, Object node) {
    ArrayList toReturn = new ArrayList();

    // get the reaching defs of this node
    DavaFlowSet beforeSet = null;
    /*
     * If this object is some sort of loop while, for dowhile, unconditional then return after set
     */
    if (node instanceof ASTWhileNode || node instanceof ASTDoWhileNode || node instanceof ASTUnconditionalLoopNode
        || node instanceof ASTForLoopNode) {
      beforeSet = getAfterSet(node);
    } else {
      beforeSet = getBeforeSet(node);
    }

    if (beforeSet == null) {
      throw new RuntimeException("Could not get reaching defs of node");
    }

    // find all reachingdefs matching this local
    for (Object temp : beforeSet) {
      // checking each def to see if it is a def of local
      if (!(temp instanceof DefinitionStmt)) {
        throw new RuntimeException("Not an instanceof DefinitionStmt" + temp);
      }
      DefinitionStmt stmt = (DefinitionStmt) temp;
      Value leftOp = stmt.getLeftOp();
      if (leftOp.toString().compareTo(local.toString()) == 0) {
        toReturn.add(stmt);
      }
    }
    return toReturn;
  }

  public void reachingDefsToString(Object node) {
    // get the reaching defs of this node
    DavaFlowSet beforeSet = null;
    /*
     * If this object is some sort of loop while, for dowhile, unconditional then return after set
     */
    if (node instanceof ASTWhileNode || node instanceof ASTDoWhileNode || node instanceof ASTUnconditionalLoopNode
        || node instanceof ASTForLoopNode) {
      beforeSet = getAfterSet(node);
    } else {
      beforeSet = getBeforeSet(node);
    }

    if (beforeSet == null) {
      throw new RuntimeException("Could not get reaching defs of node");
    }

    // find all reachingdefs matching this local
    for (Object o : beforeSet) {
      System.out.println("Reaching def:" + o);
    }
  }
}