Small fixes

* Tests creates the root node of the PDG
* Data dependency ignores nonexecutable edges
* Non-executable edges are displayed as dashed
* Small bug in the implementation of `CFGBuilder`

src/main/java/tfm/arcs/Arc.java

@@ -12,10 +12,6 @@ import java.util.Map;
 import java.util.Objects;
 
 public abstract class Arc extends DefaultEdge {
-    public Arc() {
-
-    }
-
     /** @see tfm.arcs.cfg.ControlFlowArc */
     public final boolean isControlFlowArc() {
         return this instanceof ControlFlowArc;

src/main/java/tfm/arcs/cfg/ControlFlowArc.java

 package tfm.arcs.cfg;
 
+import org.jgrapht.io.Attribute;
+import org.jgrapht.io.DefaultAttribute;
 import tfm.arcs.Arc;
 import tfm.graphs.augmented.ACFG;
 
+import java.util.Map;
+
 /**
  * An edge of the {@link tfm.graphs.CFG}, representing the direct
  * flow of control. It connects two instructions if, when the source
  * is executed, one of the possible next instructions is the destination.
  */
 public class ControlFlowArc extends Arc {
-    public ControlFlowArc() {
-    }
-
     /**
      * Represents a non-executable control flow arc, used within the {@link ACFG ACFG}.
      * Initially it had the following meaning: connecting a statement with
@@ -20,8 +21,12 @@ public class ControlFlowArc extends Arc {
      * It is used to improve control dependence, and it should be skipped when
      * computing data dependence and other analyses.
      */
-    public final static class NonExecutable extends ControlFlowArc {
-        public NonExecutable() {
+    public static final class NonExecutable extends ControlFlowArc {
+        @Override
+        public Map<String, Attribute> getDotAttributes() {
+            Map<String, Attribute> map = super.getDotAttributes();
+            map.put("style", DefaultAttribute.createAttribute("dashed"));
+            return map;
         }
     }
 }

src/main/java/tfm/arcs/pdg/ControlDependencyArc.java

@@ -9,6 +9,4 @@ import tfm.arcs.Arc;
  * {@code b} if and only if {@code b} alters the number of times {@code a} is executed.
  */
 public class ControlDependencyArc extends Arc {
-    public ControlDependencyArc() {
-    }
 }

src/main/java/tfm/graphs/CFG.java

@@ -44,9 +44,9 @@ public class CFG extends GraphWithRootNode<MethodDeclaration> {
         Set<GraphNode<?>> res = new HashSet<>();
 
         for (Arc arc : incomingEdgesOf(currentNode)) {
-            ControlFlowArc controlFlowArc = arc.asControlFlowArc();
-
-            GraphNode<?> from = this.getEdgeSource(controlFlowArc);
+            if (!arc.isExecutableControlFlowArc())
+                continue;
+            GraphNode<?> from = getEdgeSource(arc);
 
             if (!Objects.equals(startNode, from) && visited.contains(from.getId())) {
                 continue;

src/main/java/tfm/graphs/CFGBuilder.java

@@ -108,7 +108,7 @@ public class CFGBuilder extends VoidVisitorAdapter<Void> {
         hangingNodes.addAll(breakMap.remove(n.getLabel()));
         // Remove the label from the continue map; the list should have been emptied
         // in the corresponding loop.
-        if (continueMap.remove(n.getLabel()).isEmpty())
+        if (!continueMap.remove(n.getLabel()).isEmpty())
             throw new IllegalStateException("Labeled loop has not cleared its list of continue statements!");
     }
 

src/test/java/tfm/PDGTests.java

@@ -82,6 +82,7 @@ public class PDGTests {
         CFG cfg = new CFG();
         cfg.build(root);
         PDG pdg = new PDG(cfg);
+        pdg.buildRootNode("ENTER " + methodName, root);
         ctrlDepBuilder = new ControlDependencyBuilder(pdg, cfg);
         ctrlDepBuilder.analyze();
 
@@ -89,11 +90,13 @@ public class PDGTests {
         ACFG acfg = new ACFG();
         acfg.build(root);
         APDG apdg = new APDG(acfg);
+        apdg.buildRootNode("ENTER " + methodName, root);
         ctrlDepBuilder = new ControlDependencyBuilder(apdg, acfg);
         ctrlDepBuilder.analyze();
 
         // Create PPDG
         PPDG ppdg = new PPDG(acfg);
+        ppdg.buildRootNode("ENTER " + methodName, root);
         ctrlDepBuilder = new ControlDependencyBuilder(ppdg, acfg);
         ctrlDepBuilder.analyze();