Merge pull request #211 from UniVE-SSV/offset-recomputation

Cutoff recomputation in `NodeList`

lisa/lisa-sdk/src/main/java/it/unive/lisa/util/datastructures/graph/code/NodeList.java

@@ -167,10 +167,17 @@ public void removeNode(N node) {
 			cutoff.remove(target);
 		}
 
+		nodes.remove(node);
+		// need to shift all successive cutoff back by one
+		List<Integer> interesting = cutoff.stream().filter(i -> i >= target).sorted().collect(Collectors.toList());
+		cutoff.removeAll(interesting);
+		interesting.forEach(i -> cutoff.add(i - 1));
+
 		if (target != 0)
-			if (target != nodes.size() - 1) {
+			if (target != nodes.size()) { // we don't remove 1 since we want to
+											// compare wrt the 'old' position
 				N pred = nodes.get(target - 1);
-				N succ = nodes.get(target + 1);
+				N succ = nodes.get(target); // before was at target+1
 				NodeEdges<G, N, E> predEdges = extraEdges.get(pred);
 				if (predEdges != null) {
 					E seq = sequentialSingleton.newInstance(pred, succ);
@@ -184,12 +191,6 @@ public void removeNode(N node) {
 					cutoff.add(target - 1);
 			}
 
-		nodes.remove(node);
-		// need to shift all successive cutoff back by one
-		List<Integer> interesting = cutoff.stream().filter(i -> i > target).sorted().collect(Collectors.toList());
-		cutoff.removeAll(interesting);
-		interesting.forEach(i -> cutoff.add(i - 1));
-
 		recomputeOffsets();
 	}
 
@@ -252,19 +253,20 @@ public void removeEdge(E e) {
 		if (e.isUnconditional() && src == dest - 1)
 			// just add the cutoff
 			cutoff.add(src);
-		else {
-			NodeEdges<G, N, E> edges = extraEdges.get(e.getSource());
-			if (edges != null) {
-				edges.outgoing.remove(e);
-				if (edges.ingoing.isEmpty() && edges.outgoing.isEmpty())
-					extraEdges.remove(e.getSource());
-			}
-			edges = extraEdges.get(e.getDestination());
-			if (edges != null) {
-				edges.ingoing.remove(e);
-				if (edges.ingoing.isEmpty() && edges.outgoing.isEmpty())
-					extraEdges.remove(e.getDestination());
-			}
+
+		// the edge might still be inside the extraEdges
+		// if this method has been invoked by removeNode
+		NodeEdges<G, N, E> edges = extraEdges.get(e.getSource());
+		if (edges != null) {
+			edges.outgoing.remove(e);
+			if (edges.ingoing.isEmpty() && edges.outgoing.isEmpty())
+				extraEdges.remove(e.getSource());
+		}
+		edges = extraEdges.get(e.getDestination());
+		if (edges != null) {
+			edges.ingoing.remove(e);
+			if (edges.ingoing.isEmpty() && edges.outgoing.isEmpty())
+				extraEdges.remove(e.getDestination());
 		}
 	}
 

lisa/lisa-sdk/src/test/java/it/unive/lisa/program/cfg/CFGSimplificationTest.java

@@ -315,4 +315,38 @@ public void testSimplificationAtTheEndWithBranch() throws ProgramValidationExcep
 		ControlFlowStructure act = first.getControlFlowStructures().iterator().next();
 		assertEquals("Simplification did not update control flow structures", exp, act);
 	}
+
+	@Test
+	public void testIssue210() throws ProgramValidationException {
+		SourceCodeLocation unknownLocation = new SourceCodeLocation("fake", 0, 0);
+		SourceCodeLocation unknownLocation2 = new SourceCodeLocation("fake", 0, 1);
+		CompilationUnit unit = new CompilationUnit(unknownLocation, "foo", false);
+		CFG first = new CFG(new CFGDescriptor(unknownLocation, unit, true, "foo"));
+		Assignment assign = new Assignment(first, unknownLocation, new VariableRef(first, unknownLocation, "x"),
+				new Int32Literal(first, unknownLocation, 5));
+		GreaterThan gt = new GreaterThan(first, unknownLocation, new VariableRef(first, unknownLocation, "x"),
+				new Int32Literal(first, unknownLocation, 2));
+		NoOp noop = new NoOp(first, unknownLocation);
+		Length print1 = new Length(first, unknownLocation, new StringLiteral(first, unknownLocation, "f"));
+		Return ret1 = new Return(first, unknownLocation, new VariableRef(first, unknownLocation, "x"));
+
+		Length print2 = new Length(first, unknownLocation2, new StringLiteral(first, unknownLocation2, "f"));
+		Return ret2 = new Return(first, unknownLocation2, new VariableRef(first, unknownLocation2, "f"));
+
+		first.addNode(assign, true);
+		first.addNode(gt);
+		first.addNode(noop);
+		first.addNode(print1);
+		first.addNode(ret1);
+		first.addNode(print2);
+		first.addNode(ret2);
+		first.addEdge(new SequentialEdge(assign, gt));
+		first.addEdge(new TrueEdge(gt, print1));
+		first.addEdge(new SequentialEdge(print1, ret1));
+		first.addEdge(new FalseEdge(gt, print2));
+		first.addEdge(new SequentialEdge(print2, ret2));
+
+		first.simplify();
+		first.validate();
+	}
 }