* Copyright (c) 2006, 2007, 2008 Marwan Abi-Antoun, Jonathan Aldrich, Nels E. Beckman, Kevin

* Bierhoff, David Dickey, Ciera Jaspan, Thomas LaToza, Gabriel Zenarosa, and others.

*

* This file is part of Crystal.

*

* Crystal 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 3 of

* the License, or (at your option) any later version.

*

* Crystal 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 Lesser

* General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public License along with Crystal. If

* not, see <http://www.gnu.org/licenses/>.

*/

* Builds a CFG on the Eclipse AST. This class has been tested at the method level only, it has not

* been tested at higher or lower levels, though it would theoretically work.

*

* There is an interesting problem regarding when the transfer function for a node appears if it is

* a control flow statement. That is, when does the transfer statement for constructs like if and

* while occur? We have produced three possibilities:

*

* Kevin: Should appear at the point when the branching of control flow occurs. For example, the the

* conditionals of if and while.

*

* Nels: Should appear at the merge point of the control flow. This is the conditional for while,

* and the node that merges the two if branches.

*

* Ciera: Should appear after all the children have been visited. This is the merge point on if, and

* it is the node after the conditional on while.

*

* Then we decided that no one in their right mind should be using transfer functions on control

* flow anyway, so we can do whatever we want. Since I'm writing this and I have a nice design for

* the third option anyway, we're going with that.

*

* Note: Since this was written someone (Thomas? Nels?) did need to transfer on the control flow. He

* needed it at the merge point though. The subtype @link{EclipseNodeFirstCFG} handles that, and is

* currently the default control flow graph used in Crystal.

*

* Algorithm description: This class visits each node of the AST. When it visits a node, it maps the

* ASTNode to the CFGNode that it is creating. This allows a parent node to pull it out later and

* insert it into the graph. There are several other data structures to help us with control flow.

* These are described individually later. - In the previsit method, we create the node and put it

* in the map. - In the visit method, we prepare any data structures that will be needed by the

* children. - In the endvisit method, we put together the CFG for this node and its children (with

* the exception of any edges that were added by children through the data structures.

*

* @author ciera

*/

  // build simple cfg first, many edges into and out of finally

  // then traverse using a DFS. When we encounter an exception tag, track it

  // to a finally.

  // mark the entrance/exit of the finally duplicate if necessary and store

  // remember to stop within a finally and use the "original" if we hit a

  // control flow statement that overrides normal flow

  // continue until no more tags have been traversed.

  // protected EclipseCFGNode normalExit;

  protected BlockStack<EclipseCFGNode> blockStack;

  protected ExceptionMap<ASTNode, EclipseCFGNode> exceptionMap;

  protected HashMap<ASTNode, EclipseCFGNode> nodeMap;

  /**

   * Each call to endvisit will reset what the startNode and endNode is.

   */

  protected EclipseCFGNode startNode;

  protected EclipseCFGNode uberReturn;

  protected Map<ITypeBinding, EclipseCFGNode> excpReturns;

  protected EclipseCFGNode endNode;

  protected String name;

  private EclipseCFGNode undeclExit;

  public EclipseCFG(MethodDeclaration method) {

    nodeMap = new HashMap<ASTNode, EclipseCFGNode>();

    blockStack = new BlockStack<EclipseCFGNode>();

    exceptionMap = new ExceptionMap<ASTNode, EclipseCFGNode>();

    EclipseCFGNode.NEXT_ID = 0;

    createGraph(method);

  }

  public EclipseCFG() {

    nodeMap = new HashMap<ASTNode, EclipseCFGNode>();

    blockStack = new BlockStack<EclipseCFGNode>();

    exceptionMap = new ExceptionMap<ASTNode, EclipseCFGNode>();

    EclipseCFGNode.NEXT_ID = 0;

  }

  public void createGraph(MethodDeclaration method) {

    name = method.getName().getFullyQualifiedName();

    method.accept(this);

  }

  public ICFGNode<ASTNode> getStartNode() {

    return startNode;

  }

  public ICFGNode<ASTNode> getEndNode() {

    return endNode;

  }

  public ICFGNode<ASTNode> getUberReturn() {

    return uberReturn;

  }

  public ICFGNode<ASTNode> getUndeclaredExit() {

    return undeclExit;

  }

  public Map<ITypeBinding, EclipseCFGNode> getExceptionalExits() {

    return excpReturns;

  }

  public Graph getDotGraph() {

    Graph graph = new Graph(name);

    startNode.addToGraph(graph);

    return graph;

  }

  /**

   * Why might source be null? We get source from an endNode of something else. endNodes are

   * allowed to be null if a node decides to handle their own outgoing control flow. This happens

   * in breaks, returns, continues, throws, etc.

   */

  private void createEdge(EclipseCFGNode source, EclipseCFGNode sink, ILabel label) {

    if (source != null) {

      EclipseCFGEdge edge = new EclipseCFGEdge(source, sink, label);

      source.addOutputEdge(edge);

      sink.addInputEdge(edge);

    }

  }

  protected void createEdge(EclipseCFGNode source, EclipseCFGNode sink) {

    NormalLabel label = NormalLabel.getNormalLabel();

    createEdge(source, sink, label);

  }

  protected void createItrEdge(EclipseCFGNode source, EclipseCFGNode sink, boolean isEmpty) {

    IteratorLabel label = IteratorLabel.getItrLabel(isEmpty);

    createEdge(source, sink, label);

  }

  protected void createBooleanEdge(EclipseCFGNode source, EclipseCFGNode sink, boolean boolValue) {

    BooleanLabel label = BooleanLabel.getBooleanLabel(boolValue);

    createEdge(source, sink, label);

  }

  protected void createEdge(EclipseCFGNode source, EclipseCFGNode sink, ITypeBinding exception) {

    ExceptionalLabel label = new ExceptionalLabel(exception);

    createEdge(source, sink, label);

  }

  protected void createEdge(EclipseCFGNode source, EclipseCFGNode sink, Expression switchCase) {

    SwitchLabel label = new SwitchLabel(switchCase);

    createEdge(source, sink, label);

  }

  private void makeListEdges(EclipseCFGNode init, List<ASTNode> list, EclipseCFGNode parent) {

    EclipseCFGNode current, last = init;

    if (last != null) {

      parent.setStart(last.getStart());

    }

    for (ASTNode node : list) {

      current = nodeMap.get(node);

      if (last != null) {

        createEdge(last.getEnd(), current.getStart());

      }

      else

        parent.setStart(current.getStart());

      last = current;

    }

    if (last != null) {

      createEdge(last.getEnd(), parent);

    }

  }

  @Override

  public void preVisit(ASTNode node) {

    EclipseCFGNode cfgNode = new EclipseCFGNode(node);

    nodeMap.put(node, cfgNode);

  }

  /**

   * Creates an edge DIRECTLY from source to the proper finally blocks, and then from the finally

   * blocks DIRECTLY to the destination. By directly, this means that it won't call getEnd or

   * getStart. It uses the exceptionToStopAt to determine which finally blocks to grab. It will

   * also make the edge from the source to the finally block have this exception. A normal edge

   * will be used when exceptionToStopAt is null

   */

  protected void hookFinally(EclipseCFGNode source, ITypeBinding exceptionToStopAt,

      EclipseCFGNode dest) {

    Stack<EclipseCFGNode> finallyStack = exceptionMap.getFinallyToException(exceptionToStopAt);

    EclipseCFGNode last = null, current = null, cloneCurrent = null, first = null;

    while (!finallyStack.isEmpty()) {

      current = finallyStack.pop();

      cloneCurrent = copySubgraph(current);

      if (first == null)

        first = cloneCurrent;

      if (last != null)

        createEdge(last.getEnd(), cloneCurrent.getStart());

      last = cloneCurrent;

    }

    if (first != null) { // there is a finally

      if (exceptionToStopAt == null)

        createEdge(source, first.getStart());

      else

        createEdge(source, first.getStart(), exceptionToStopAt);

      createEdge(last.getEnd(), dest);

    }

    else {

      // no finally

      if (exceptionToStopAt == null)

        createEdge(source, dest);

      else

        createEdge(source, dest, exceptionToStopAt);

    }

  }

  private EclipseCFGNode copySubgraph(EclipseCFGNode current) {

    HashMap<EclipseCFGNode, EclipseCFGNode> cloneMap =

        new HashMap<EclipseCFGNode, EclipseCFGNode>();

    EclipseCFGNode cloneNode;

    copySubgraphRecur(current.getStart(), current.getEnd(), cloneMap);

    cloneNode = cloneMap.get(current);

    return cloneNode;

  }

  /**

   * @param current

   * @return

   */

  private EclipseCFGNode copySubgraphRecur(EclipseCFGNode current, EclipseCFGNode stopNode,

      HashMap<EclipseCFGNode, EclipseCFGNode> cloneMap) {

    ASTNode node = current.getASTNode();

    EclipseCFGNode clone = new EclipseCFGNode(node);

    EclipseCFGNode start = current.getStart();

    EclipseCFGNode end = current.getEnd();

    clone.setName(current.getName());

    cloneMap.put(current, clone);

    if (current == stopNode || node instanceof ReturnStatement

        || node instanceof ThrowStatement || node instanceof BreakStatement

        || node instanceof ContinueStatement) {

      for (EclipseCFGEdge edge : current.getOutputs()) {

        EclipseCFGEdge cloneEdge =

            new EclipseCFGEdge(clone, edge.getSink(), edge.getLabel());

        edge.getSink().addInputEdge(cloneEdge);

        clone.addOutputEdge(cloneEdge);

      }

    }

    else {

      for (EclipseCFGEdge edge : current.getOutputs()) {

        EclipseCFGNode cloneSink = copySubgraphRecur(edge.getSink(), stopNode, cloneMap);

        EclipseCFGEdge cloneEdge = new EclipseCFGEdge(clone, cloneSink, edge.getLabel());

        cloneSink.addInputEdge(cloneEdge);

        clone.addOutputEdge(cloneEdge);

      }

    }

    if (cloneMap.containsKey(start))

      start = cloneMap.get(start);

    if (cloneMap.containsKey(end))

      end = cloneMap.get(end);

    clone.setStart(start);

    clone.setEnd(end);

    return clone;

  }

  /* CONTROL FLOW */

  @Override

  public void endVisit(AssertStatement node) {

    EclipseCFGNode assertNode = nodeMap.get(node);

    EclipseCFGNode expNode = nodeMap.get(node.getExpression());

    EclipseCFGNode messageNode = nodeMap.get(node.getMessage());

    EclipseCFGNode falsePath = new EclipseCFGNode(null);

    ITypeBinding binding = node.getAST().resolveWellKnownType("java.lang.Throwable");

    EclipseCFGNode catchNode = exceptionMap.getCatchNode(binding);

    createEdge(assertNode, expNode.getStart());

    assertNode.setStart(expNode.getStart());

    createBooleanEdge(expNode.getEnd(), assertNode, true);

    falsePath.setName("POP!");

    if (messageNode != null) {

      createBooleanEdge(expNode.getEnd(), messageNode.getStart(), false);

      createEdge(messageNode.getEnd(), falsePath);

    }

    else {

      createBooleanEdge(expNode.getEnd(), falsePath, false);

    }

    hookFinally(falsePath, binding, catchNode);

  }

  @Override

  public boolean visit(BreakStatement node) {

    EclipseCFGNode breakStmnt = nodeMap.get(node);

    blockStack.overrideIfExists(node, breakStmnt, null);

    return true;

  }

  @Override

  public void endVisit(BreakStatement node) {

    EclipseCFGNode breakStmnt = nodeMap.get(node);

    String label = (node.getLabel() != null) ? node.getLabel().getIdentifier() : null;

    EclipseCFGNode breakPoint = blockStack.getBreakPoint(label);

    breakStmnt.setName("break");

    hookFinally(breakStmnt, null, breakPoint);

    breakStmnt.setEnd(null);

  }

  @Override

  public void endVisit(ContinueStatement node) {

    EclipseCFGNode continueStmnt = nodeMap.get(node);

    String label = (node.getLabel() != null) ? node.getLabel().getIdentifier() : null;

    EclipseCFGNode continuePoint = blockStack.getContinuePoint(label);

    continueStmnt.setName("continue");

    hookFinally(continueStmnt, null, continuePoint);

    continueStmnt.setEnd(null);

  }

  @Override

  public void endVisit(ConditionalExpression node) {

    EclipseCFGNode ifExp = nodeMap.get(node);

    EclipseCFGNode cond = nodeMap.get(node.getExpression());

    EclipseCFGNode thenClause = nodeMap.get(node.getThenExpression());

    EclipseCFGNode elseClause = nodeMap.get(node.getElseExpression());

    createBooleanEdge(cond.getEnd(), thenClause.getStart(), true);

    createEdge(thenClause.getEnd(), ifExp);

    createBooleanEdge(cond.getEnd(), elseClause.getStart(), false);

    createEdge(elseClause.getEnd(), ifExp);

    ifExp.setStart(cond.getStart());

    ifExp.setName("? :");

  }

  @Override

  public boolean visit(DoStatement node) {

    EclipseCFGNode doEnd = nodeMap.get(node);

    EclipseCFGNode doBegin = new EclipseCFGNode(null);

    blockStack.pushUnlabeled(node, doEnd, doBegin);

    doEnd.setStart(doBegin);

    return true;

  }

  @Override

  public void endVisit(DoStatement node) {

    EclipseCFGNode doEnd = nodeMap.get(node);

    EclipseCFGNode cond = nodeMap.get(node.getExpression());

    EclipseCFGNode body = nodeMap.get(node.getBody());

    EclipseCFGNode doBegin = doEnd.getStart();

    createEdge(doBegin, body.getStart());

    createEdge(body.getEnd(), cond.getStart());

    createBooleanEdge(cond.getEnd(), body.getStart(), true);

    createBooleanEdge(cond.getEnd(), doEnd, false);

    blockStack.popUnlabeled();

    doBegin.setName("do");

    doEnd.setName("od");

  }

  @Override

  public boolean visit(EnhancedForStatement node) {

    EclipseCFGNode eforEnd = nodeMap.get(node);

    EclipseCFGNode eforBegin = new EclipseCFGNode(null);

    blockStack.pushUnlabeled(node, eforEnd, eforBegin);

    eforEnd.setStart(eforBegin);

    return true;

  }

  @Override

  public void endVisit(EnhancedForStatement node) {

    EclipseCFGNode eforEnd = nodeMap.get(node);

    EclipseCFGNode list = nodeMap.get(node.getExpression());

    EclipseCFGNode body = nodeMap.get(node.getBody());

    EclipseCFGNode param = nodeMap.get(node.getParameter());

    EclipseCFGNode eforBegin = eforEnd.getStart();

    eforEnd.setStart(list.getStart());

    createEdge(list.getEnd(), eforBegin);

    createItrEdge(eforBegin, param.getStart(), false);

    createItrEdge(eforBegin, eforEnd, true);

    createEdge(param.getEnd(), body.getStart());

    createEdge(body.getEnd(), eforBegin);

    blockStack.popUnlabeled();

    eforBegin.setName("efor");

    eforEnd.setName("rofe");

  }

  @Override

  public boolean visit(ForStatement node) {

    EclipseCFGNode forEnd = nodeMap.get(node);

    EclipseCFGNode forBegin = new EclipseCFGNode(null);

    blockStack.pushUnlabeled(node, forEnd, forBegin);

    forEnd.setStart(forBegin);

    return true;

  }

  @Override

  public void endVisit(ForStatement node) {

    EclipseCFGNode forEnd = nodeMap.get(node);

    EclipseCFGNode cond = nodeMap.get(node.getExpression());

    EclipseCFGNode body = nodeMap.get(node.getBody());

    EclipseCFGNode forBegin = forEnd.getStart();

    EclipseCFGNode current, last = null;

    // first, run the initializers

    for (ASTNode init : (List<ASTNode>) node.initializers()) {

      current = nodeMap.get(init);

      if (last != null)

        createEdge(last.getEnd(), current.getStart());

      else

        forEnd.setStart(current.getStart());

      last = current;

    }

    if (cond != null) {

      if (last != null)

        createEdge(last.getEnd(), cond.getStart());

      else

        forEnd.setStart(cond.getStart());

      createBooleanEdge(cond.getEnd(), forEnd, false);

      createBooleanEdge(cond.getEnd(), body.getStart(), true);

    }

    else {

      if (last != null)

        createEdge(last.getEnd(), body.getStart());

      else

        forEnd.setStart(body.getStart());

    }

    // notice that we are inserting forbegin after the initializers,

    // but just before the updaters. This is so that

    // when we hit a continue, we jump to the updaters and NOT the

    // inializers.

    // it is a little weird since the begin point is after the body, but

    // since it's

    // a loop, it's also before the body. :)

    // we also changed forEnd.getStart so that it no longer returns forBegin

    // (see above)

    createEdge(body.getEnd(), forBegin);

    last = forBegin;

    for (ASTNode update : (List<ASTNode>) node.updaters()) {

      current = nodeMap.get(update);

      createEdge(last.getEnd(), current.getStart());

      last = current;

    }

    if (cond != null)

      createEdge(last.getEnd(), cond.getStart());

    else

      createEdge(last.getEnd(), body.getStart());

    blockStack.popUnlabeled();

    forBegin.setName("for");

    forEnd.setName("rof");

  }

  @Override

  public boolean visit(LabeledStatement node) {

    blockStack.pushLabeled(node.getLabel().getIdentifier(), node.getBody());

    return true;

  }

  @Override

  public void endVisit(LabeledStatement node) {

    EclipseCFGNode label = nodeMap.get(node);

    EclipseCFGNode body = nodeMap.get(node.getBody());

    createEdge(body.getEnd(), label);

    blockStack.popLabeled();

    label.setName("label " + node.getLabel().toString());

    label.setStart(body.getStart());

  }

  @Override

  public boolean visit(IfStatement node) {

    EclipseCFGNode ifStmnt = nodeMap.get(node);

    blockStack.overrideIfExists(node, ifStmnt, null);

    return true;

  }

  @Override

  public void endVisit(IfStatement node) {

    EclipseCFGNode ifStmnt = nodeMap.get(node);

    EclipseCFGNode cond = nodeMap.get(node.getExpression());

    EclipseCFGNode thenClause = nodeMap.get(node.getThenStatement());

    createBooleanEdge(cond.getEnd(), thenClause.getStart(), true);

    createEdge(thenClause.getEnd(), ifStmnt);

    if (node.getElseStatement() != null) {

      EclipseCFGNode elseClause = nodeMap.get(node.getElseStatement());

      createBooleanEdge(cond.getEnd(), elseClause.getStart(), false);

      createEdge(elseClause.getEnd(), ifStmnt);

    }

    else {

      createBooleanEdge(cond.getEnd(), ifStmnt, false);

    }

    ifStmnt.setStart(cond.getStart());

    ifStmnt.setName("if");

  }

  @Override

  public boolean visit(MethodDeclaration node) {

    EclipseCFGNode method = nodeMap.get(node);

    EclipseCFGNode implicitCatch;

    excpReturns = new HashMap<ITypeBinding, EclipseCFGNode>();

    undeclExit = new EclipseCFGNode(null);

    createEdge(undeclExit, method);

    undeclExit.setName("(error)");

    exceptionMap.pushCatch(undeclExit, node

        .getAST().resolveWellKnownType("java.lang.Throwable"));

    for (Name name : (List<Name>) node.thrownExceptions()) {

      implicitCatch = new EclipseCFGNode(null);

      createEdge(implicitCatch, method);

      implicitCatch.setName("(throws)");

      exceptionMap.pushCatch(implicitCatch, (ITypeBinding) name.resolveBinding());

      excpReturns.put(name.resolveTypeBinding(), implicitCatch);

    }

    uberReturn = new EclipseCFGNode(null);

    uberReturn.setName("(uber-return)");

    createEdge(uberReturn, method);

    if (node.isConstructor()) {

      TypeDeclaration type = (TypeDeclaration) node.getParent();

      for (FieldDeclaration field : type.getFields()) {

        if (!Modifier.isStatic(field.getModifiers()))

          field.accept(this);

      }

    }

    // visit the statements individually.

    // we'll need to put them together by hand later so we can insert the

    // field decls

    // into constructors.

    for (ASTNode param : (List<ASTNode>) node.parameters())

      param.accept(this);

    if (node.getBody() != null)

      for (ASTNode stmt : (List<ASTNode>) node.getBody().statements())

        stmt.accept(this);

    return false;

  }

  @Override

  public void endVisit(MethodDeclaration node) {

    EclipseCFGNode method = nodeMap.get(node);

    EclipseCFGNode body = null;

    EclipseCFGNode current, last = null;

    // connect params together

    for (ASTNode arg : (List<ASTNode>) node.parameters()) {

      current = nodeMap.get(arg);

      if (last != null)

        createEdge(last.getEnd(), current.getStart());

      last = current;

    }

    if (node.isConstructor())

      body = setUpConstructorBody(node);

    else

      body = setUpMethodBody(node);

    // connect the end of the body to the fall-off return

    createEdge(body.getEnd(), uberReturn);

    if (last != null) {

      createEdge(last.getEnd(), body.getStart());

      method.setStart(nodeMap.get(node.parameters().get(0)).getStart());

    }

    else

      method.setStart(body.getStart());

    // finish off exceptions

    for (int ndx = 0; ndx < node.thrownExceptions().size(); ndx++)

      exceptionMap.popCatch();

    // exceptionMap.popFinally();

    startNode = method.getStart();

    endNode = method;

    method.setName("Declare " + node.getName().getIdentifier());

  }

  /**

   * set up the body part of a constructor declaration. Return the node that represents the body.

   *

   * @param node

   * @return

   */

  private EclipseCFGNode setUpConstructorBody(MethodDeclaration node) {

    EclipseCFGNode last = null, current = null;

    List<ASTNode> statements = new ArrayList<ASTNode>(node.getBody().statements());

    ASTNode firstStmt = null;

    EclipseCFGNode body = new EclipseCFGNode(node.getBody());

    // connect field declarations with initializers together

    for (FieldDeclaration field : ((TypeDeclaration) node.getParent()).getFields()) {

      if (Modifier.isStatic(field.getModifiers()))

        continue;

      for (VariableDeclarationFragment frag : (List<VariableDeclarationFragment>) field

          .fragments()) {

        if (frag.getInitializer() != null) {

          current = nodeMap.get(frag);

          if (last != null) {

            createEdge(last.getEnd(), current.getStart());

            current.setStart(last.getStart());

          }

          last = current;

        }

      }

    }

    // now figure out where to insert the initializers

    if (statements.size() > 0) {

      firstStmt = statements.get(0);

      if (firstStmt instanceof SuperConstructorInvocation) {

        current = nodeMap.get(firstStmt);

        if (last != null) {

          createEdge(current.getEnd(), last.getStart());

          current.setEnd(last.getEnd());

        }

        last = current;

        statements.remove(firstStmt);

      }

      else if (firstStmt instanceof ConstructorInvocation) {

        last = null;

      }

    }

    makeListEdges(last, statements, body);

    return body;

  }

  /**

   * set up the body part of a method declaration. Return the node that represents the body.

   *

   * @param node

   * @return

   */

  private EclipseCFGNode setUpMethodBody(MethodDeclaration node) {

    EclipseCFGNode body = new EclipseCFGNode(node.getBody());

    if (node.getBody() != null)

      makeListEdges(null, node.getBody().statements(), body);

    return body;

  }

  @Override

  public void endVisit(ReturnStatement node) {

    EclipseCFGNode ret = nodeMap.get(node);

    EclipseCFGNode exp = nodeMap.get(node.getExpression());

    if (exp != null) {

      createEdge(exp.getEnd(), ret);

      ret.setStart(exp.getStart());

    }

    hookFinally(ret, (ITypeBinding) null, uberReturn);

    ret.setEnd(null);

    ret.setName("return");

  }

  @Override

  public boolean visit(SwitchStatement node) {

    EclipseCFGNode switchEnd = nodeMap.get(node);

    EclipseCFGNode switchBegin = new EclipseCFGNode(null);

    blockStack.pushUnlabeled(node, switchEnd, null);

    switchEnd.setStart(switchBegin);

    return true;

  }

  @Override

  public void endVisit(SwitchStatement node) {

    EclipseCFGNode switchEnd = nodeMap.get(node);

    EclipseCFGNode switchBegin = switchEnd.getStart();

    EclipseCFGNode exp = nodeMap.get(node.getExpression());

    EclipseCFGNode last = null;

    boolean hasDefault = false;

    List<ASTNode> stmnts = (List<ASTNode>) node.statements();

    createEdge(switchBegin, exp.getStart());

    last = switchEnd;

    for (int ndx = stmnts.size() - 1; ndx >= 0; ndx--) {

      ASTNode currentAST = stmnts.get(ndx);

      EclipseCFGNode current = nodeMap.get(currentAST);

      if (currentAST instanceof SwitchCase) {

        createEdge(exp.getEnd(), current.getStart(), ((SwitchCase) currentAST)

            .getExpression());

        createEdge(current.getEnd(), last);

        hasDefault = hasDefault || ((SwitchCase) currentAST).getExpression() == null;

        continue;

      }

      createEdge(current.getEnd(), last);

      last = current.getStart();

    }

    if (!hasDefault)

      createEdge(exp.getEnd(), switchEnd, (Expression) null);

    blockStack.popUnlabeled();

    switchBegin.setName("switch");

    switchEnd.setName("hctiws");

  }

  @Override

  public boolean visit(CatchClause node) {

    EclipseCFGNode catchNode = nodeMap.get(node);

    blockStack.overrideIfExists(node, catchNode, null);

    return true;

  }

  @Override

  public void endVisit(CatchClause node) {

    EclipseCFGNode catchNode = nodeMap.get(node);

    EclipseCFGNode declNode = nodeMap.get(node.getException());

    EclipseCFGNode bodyNode = nodeMap.get(node.getBody());

    createEdge(declNode.getEnd(), bodyNode.getStart());

    createEdge(bodyNode.getEnd(), catchNode);

    catchNode.setStart(declNode.getStart());

    catchNode.setName("catch");

  }

  @Override

  public void endVisit(ThrowStatement node) {

    EclipseCFGNode throwNode = nodeMap.get(node);

    EclipseCFGNode expNode = nodeMap.get(node.getExpression());

    ITypeBinding binding = node.getExpression().resolveTypeBinding();

    EclipseCFGNode catchNode = exceptionMap.getCatchNode(binding);

    EclipseCFGNode current = throwNode;

    createEdge(expNode.getEnd(), throwNode);

    hookFinally(throwNode, binding, catchNode.getStart());

    throwNode.setStart(expNode.getStart());

    throwNode.setName("throw");

    throwNode.setEnd(null);

  }

  @Override

  public boolean visit(TryStatement node) {

    EclipseCFGNode tryNode = nodeMap.get(node);

    EclipseCFGNode finallyNode = null, catchNode, bodyNode;

    blockStack.overrideIfExists(node, tryNode, null);

    // first analyze the finally

    if (node.getFinally() != null) {

      node.getFinally().accept(this);

      finallyNode = nodeMap.get(node.getFinally());

      exceptionMap.pushFinally(finallyNode);

    }

    // then analyze the catches

    for (CatchClause catchClause : (List<CatchClause>) node.catchClauses()) {

      catchClause.accept(this);

      catchNode = nodeMap.get(catchClause);

      exceptionMap

          .pushCatch(catchNode, catchClause.getException().getType().resolveBinding());

    }

    // analyze body now that the exceptionMap is set up

    node.getBody().accept(this);

    bodyNode = nodeMap.get(node.getBody());

    // remove the catches

    for (int ndx = 0; ndx < node.catchClauses().size(); ndx++)

      exceptionMap.popCatch();

    // set up normal flow

    if (finallyNode != null) {

      exceptionMap.popFinally();

      if (bodyNode.getEnd() != null) {

        // if the try has no normal ending, don't attach it to the

        // finally

        createEdge(bodyNode.getEnd(), finallyNode.getStart());

        createEdge(finallyNode.getEnd(), tryNode);

      }

    }

    else

      createEdge(bodyNode.getEnd(), tryNode);

    // set up exceptional flow

    for (CatchClause catchClause : (List<CatchClause>) node.catchClauses()) {

      catchNode = nodeMap.get(catchClause);

      if (finallyNode != null)

        createEdge(catchNode.getEnd(), finallyNode.getStart());

      else

        createEdge(catchNode.getEnd(), tryNode);

    }

    tryNode.setStart(bodyNode.getStart());

    tryNode.setName("try");

    return false;

  }

  @Override

  public boolean visit(WhileStatement node) {

    EclipseCFGNode whileEnd = nodeMap.get(node);

    EclipseCFGNode whileBegin = new EclipseCFGNode(null);

    blockStack.pushUnlabeled(node, whileEnd, whileBegin);

    whileEnd.setStart(whileBegin);

    return true;

  }

  @Override

  public void endVisit(WhileStatement node) {

    EclipseCFGNode whileEnd = nodeMap.get(node);

    EclipseCFGNode cond = nodeMap.get(node.getExpression());

    EclipseCFGNode body = nodeMap.get(node.getBody());

    EclipseCFGNode whileBegin = whileEnd.getStart();

    createEdge(whileBegin, cond.getStart());

    createBooleanEdge(cond.getEnd(), whileEnd, false);

    createBooleanEdge(cond.getEnd(), body.getStart(), true);

    createEdge(body.getEnd(), cond.getStart());

    blockStack.popUnlabeled();

    whileBegin.setName("while");

    whileEnd.setName("elihw");

  }

  /* BLOCKS */

  @Override

  public boolean visit(Block node) {

    EclipseCFGNode block = nodeMap.get(node);

    blockStack.overrideIfExists(node, block, null);

    return true;

  }

  @Override

  public void endVisit(Block node) {

    EclipseCFGNode bNode = nodeMap.get(node);

    makeListEdges(null, node.statements(), bNode);

    bNode.setName("{}");

  }

  @Override

  public void endVisit(ExpressionStatement node) {

    EclipseCFGNode exp = nodeMap.get(node.getExpression());

    EclipseCFGNode stmnt = nodeMap.get(node);

    createEdge(exp.getEnd(), stmnt);

    stmnt.setStart(exp.getStart());

  }

  @Override

  public void endVisit(ParenthesizedExpression node) {

    EclipseCFGNode exp = nodeMap.get(node.getExpression());

    nodeMap.put(node, exp);

  }

  @Override

  public void endVisit(SwitchCase node) {

    if (node.getExpression() != null) {

      EclipseCFGNode exp = nodeMap.get(node.getExpression());

      nodeMap.put(node, exp);

    }

    else {

      EclipseCFGNode defCase = nodeMap.get(node);

      defCase.setName("default");

    }

  }

  @Override

  public void endVisit(SynchronizedStatement node) {

    // TODO duplicate for all possible ways to get out of the sync!

    EclipseCFGNode sync = nodeMap.get(node);

    EclipseCFGNode exp = nodeMap.get(node.getExpression());

    EclipseCFGNode body = nodeMap.get(node.getBody());

    createEdge(exp.getEnd(), body.getStart());

    createEdge(body.getEnd(), sync);

    sync.setStart(exp.getStart());

  }

  /* VARIABLE DECLARATIONS */

  @Override

  public void endVisit(VariableDeclarationExpression node) {

    EclipseCFGNode decls = nodeMap.get(node);

    EclipseCFGNode typeNode = nodeMap.get(node.getType());

    EclipseCFGNode current, last = null;

    createEdge(decls, typeNode.getStart());

    last = typeNode;

    for (ASTNode frag : (List<ASTNode>) node.fragments()) {

      current = nodeMap.get(frag);

      createEdge(last.getEnd(), current.getStart());

      last = current;

    }

    decls.setStart(decls);

    decls.setEnd(last.getEnd());

    decls.setName(node.getType().toString());

  }

  @Override

  public void endVisit(VariableDeclarationFragment node) {

    EclipseCFGNode decl = handleVariableDecl(node, null);

    decl.setName(node.getName().getIdentifier());

  }

  @Override

  public void endVisit(VariableDeclarationStatement node) {

    EclipseCFGNode decls = nodeMap.get(node);

    EclipseCFGNode typeNode = nodeMap.get(node.getType());

    EclipseCFGNode current, last = null;

    createEdge(decls, typeNode.getStart());

    last = typeNode;

    for (ASTNode frag : (List<ASTNode>) node.fragments()) {

      current = nodeMap.get(frag);

      createEdge(last.getEnd(), current.getStart());

      last = current;

    }

    decls.setStart(decls);

    decls.setEnd(last.getEnd());

    decls.setName(node.getType().toString());

  }

  @Override

  public void endVisit(SingleVariableDeclaration node) {

    EclipseCFGNode type = nodeMap.get(node.getType());

    EclipseCFGNode decl = handleVariableDecl(node, type);

    decl.setName(node.getType().toString() + " " + node.getName().getIdentifier());

  }

  private EclipseCFGNode handleVariableDecl(VariableDeclaration node, EclipseCFGNode startPoint) {

    EclipseCFGNode decl = nodeMap.get(node);

    EclipseCFGNode name = nodeMap.get(node.getName());

    EclipseCFGNode current = null;

    if (startPoint != null) {

      current = startPoint.getEnd();

    }

    if (node.getInitializer() != null) {

      EclipseCFGNode init = nodeMap.get(node.getInitializer());

      if (current != null)

        createEdge(current, init.getStart());

      else

        startPoint = init;

      current = init.getEnd();

    }

    if (current != null)

      createEdge(current, name.getStart());

    else

      startPoint = name;

    createEdge(name.getEnd(), decl);

    decl.setStart(startPoint.getStart());

    return decl;

  }

  /* EXPRESSIONS */

  @Override

  public void endVisit(ArrayAccess node) {

    EclipseCFGNode arrayAccess = nodeMap.get(node);

    EclipseCFGNode array = nodeMap.get(node.getArray());

    EclipseCFGNode index = nodeMap.get(node.getIndex());

    createEdge(array.getEnd(), index.getStart());

    createEdge(index.getEnd(), arrayAccess);

    arrayAccess.setStart(array.getStart());

  }

  @Override

  public void endVisit(ArrayCreation node) {

    EclipseCFGNode arrayCreation = nodeMap.get(node);

    if (node.getInitializer() == null)

      makeListEdges(null, node.dimensions(), arrayCreation);

    else {

      EclipseCFGNode arrayInit = nodeMap.get(node.getInitializer());

      createEdge(arrayInit.getEnd(), arrayCreation);

      arrayCreation.setStart(arrayInit.getStart());

    }

  }

  @Override

  public void endVisit(ArrayInitializer node) {

    EclipseCFGNode arrayInit = nodeMap.get(node);

    makeListEdges(null, node.expressions(), arrayInit);

  }

  @Override

  public void endVisit(Assignment node) {

    EclipseCFGNode rhs = nodeMap.get(node.getRightHandSide());

    EclipseCFGNode lhs = nodeMap.get(node.getLeftHandSide());

    EclipseCFGNode assign = nodeMap.get(node);

    createEdge(rhs.getEnd(), lhs.getStart());

    createEdge(lhs.getEnd(), assign);

    assign.setStart(rhs.getStart());

    assign.setEnd(assign);

    assign.setName(node.getOperator().toString());

  }

  @Override

  public void endVisit(CastExpression node) {

    EclipseCFGNode cast = nodeMap.get(node);

    EclipseCFGNode expression = nodeMap.get(node.getExpression());

    createEdge(expression.getEnd(), cast);

    cast.setStart(expression.getStart());

  }

  @Override

  public void endVisit(ConstructorInvocation node) {

    EclipseCFGNode constructor = nodeMap.get(node);

    makeListEdges(null, (List<ASTNode>) node.arguments(), constructor);

  }

  @Override

  public void endVisit(FieldAccess node) {

    EclipseCFGNode field = nodeMap.get(node);

    EclipseCFGNode expression = nodeMap.get(node.getExpression());

    EclipseCFGNode name = nodeMap.get(node.getName());

    createEdge(expression.getEnd(), name.getStart());

    createEdge(name.getEnd(), field);

    field.setStart(expression.getStart());

    field.setName(".");

  }

  @Override

  public void endVisit(InfixExpression node) {

    EclipseCFGNode infix = nodeMap.get(node);

    EclipseCFGNode lhs = nodeMap.get(node.getLeftOperand());

    EclipseCFGNode rhs = nodeMap.get(node.getRightOperand());

    Operator op = node.getOperator();

    // short circuiting

    if (op.equals(Operator.CONDITIONAL_AND) || op.equals(Operator.CONDITIONAL_OR)) {

      boolean isAnd = node.getOperator().equals(InfixExpression.Operator.CONDITIONAL_AND);

      List<Expression> operands = new ArrayList<Expression>();

      EclipseCFGNode last = null;

      operands.add(node.getLeftOperand());

      operands.add(node.getRightOperand());

      operands.addAll(node.extendedOperands());

      int ndx = 0;

      for (Expression opNode : operands) {

        EclipseCFGNode operand = nodeMap.get(opNode);

        if (last != null)

          createBooleanEdge(last.getEnd(), operand.getStart(), isAnd);

        createBooleanEdge(operand.getEnd(), infix, !isAnd);

        if (ndx == operands.size() - 1)

          createBooleanEdge(operand.getEnd(), infix, isAnd);

        last = operand;

        ndx++;

      }

    }

    else {

      createEdge(lhs.getEnd(), rhs.getStart());

      makeListEdges(rhs, (List<ASTNode>) node.extendedOperands(), infix);

    }

    infix.setName(node.getOperator().toString());

    infix.setStart(lhs.getStart());

  }

  @Override

  public void endVisit(InstanceofExpression node) {

    EclipseCFGNode instanceTest = nodeMap.get(node);

    EclipseCFGNode lhs = nodeMap.get(node.getLeftOperand());

    EclipseCFGNode rhs = nodeMap.get(node.getRightOperand());

    createEdge(lhs.getEnd(), rhs.getStart());

    createEdge(rhs.getEnd(), instanceTest);

    instanceTest.setStart(lhs.getStart());

    instanceTest.setName("instanceof");

  }

  @Override

  public void endVisit(ClassInstanceCreation node) {

    EclipseCFGNode constructor = nodeMap.get(node);

    // Normal edges

    makeListEdges(null, (List<ASTNode>) node.arguments(), constructor);

    // handle exception edges

    for (ITypeBinding exception : node.resolveConstructorBinding().getExceptionTypes()) {

      EclipseCFGNode catchNode = exceptionMap.getCatchNode(exception);

      if (catchNode != null)

        createEdge(constructor, catchNode.getStart(), exception);

      // else

      // createEdge(invocation, normalExit, exception);

    }

    constructor.setName("new " + node.getType().resolveBinding().getName());

  }

  @Override

  public void endVisit(MethodInvocation node) {