diff --git a/plugins/org.eclipse.xtext/META-INF/MANIFEST.MF b/plugins/org.eclipse.xtext/META-INF/MANIFEST.MF
index d99268e04..42a7480e9 100644
--- a/plugins/org.eclipse.xtext/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.xtext/META-INF/MANIFEST.MF
@@ -15,6 +15,7 @@ Export-Package: org.eclipse.xtext,
  org.eclipse.xtext.common.services,
  org.eclipse.xtext.conversion,
  org.eclipse.xtext.conversion.impl,
+ org.eclipse.xtext.debug;x-internal:=true,
  org.eclipse.xtext.diagnostics,
  org.eclipse.xtext.documentation,
  org.eclipse.xtext.documentation.impl,
diff --git a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/debug/IStratumBreakpointSupport.java b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/debug/IStratumBreakpointSupport.java
new file mode 100644
index 000000000..39dc22989
--- /dev/null
+++ b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/debug/IStratumBreakpointSupport.java
@@ -0,0 +1,29 @@
+/*******************************************************************************
+ * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.debug;
+
+import org.eclipse.xtext.resource.XtextResource;
+
+import com.google.inject.ImplementedBy;
+
+/**
+ * @author Sven Efftinge - Initial contribution and API
+ */
+@ImplementedBy(IStratumBreakpointSupport.DefaultImpl.class)
+public interface IStratumBreakpointSupport {
+
+	public boolean isValidLineForBreakPoint(XtextResource resource, int line);
+	
+	public static class DefaultImpl implements IStratumBreakpointSupport {
+
+		public boolean isValidLineForBreakPoint(XtextResource resource, int line) {
+			return false;
+		}
+		
+	}
+}
diff --git a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/SmapSupport.java b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/SmapSupport.java
index e10a7e718..0a6d90ab0 100644
--- a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/SmapSupport.java
+++ b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/SmapSupport.java
@@ -24,6 +24,7 @@ import java.util.Set;
 import org.apache.log4j.Logger;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.emf.common.util.URI;
+import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.xtext.LanguageInfo;
 import org.eclipse.xtext.resource.IResourceServiceProvider;
 import org.eclipse.xtext.smap.SDEInstaller;
@@ -43,11 +44,14 @@ public class SmapSupport {
 	
 	@Inject private IResourceServiceProvider.Registry serviceProviderRegistry;
 
-	public String generateSmap(AbstractTraceRegion rootTraceRegion, String outputFileName) {
+	public @Nullable String generateSmap(AbstractTraceRegion rootTraceRegion, String outputFileName) {
 		final Set<LineMapping> lineData = newLinkedHashSet();
 		createSmapInfo(rootTraceRegion, lineData);
+		if (lineData.isEmpty())
+			return null;
 		List<LineMapping> lineInfo = normalizeLineInfo(lineData);
-
+		if (lineInfo.isEmpty())
+			return null;
 		return toSmap(outputFileName, lineInfo);
 	}
 
@@ -98,7 +102,8 @@ public class SmapSupport {
 				current = new LineMapping(mapping.sourceStartLine, mapping.targetStartLine, mapping.targetEndLine, mapping.source);
 			}
 		}
-		result.add(0, current);
+		if (current != null)
+			result.add(0, current);
 		return result;
 	}