[258284] Don't allow a reverse-finish when in main() since GDB will reject it.

dsf-gdb/org.eclipse.cdt.dsf.gdb/src/org/eclipse/cdt/dsf/gdb/service/GDBRunControl_7_0.java

@@ -179,13 +179,43 @@ public class GDBRunControl_7_0 extends MIRunControl implements IReverseRunContro
 	}
 
     /** @since 2.0 */
-	public void canReverseStep(IExecutionDMContext context, StepType stepType, DataRequestMonitor<Boolean> rm) {
+	public void canReverseStep(final IExecutionDMContext context, StepType stepType, final DataRequestMonitor<Boolean> rm) {
 	   	if (context instanceof IContainerDMContext) {
     		rm.setData(false);
     		rm.done();
     		return;
     	}
 
+    	if (stepType == StepType.STEP_RETURN) {
+    		// A step return will always be done in the top stack frame.
+    		// If the top stack frame is the only stack frame, it does not make sense
+    		// to do a step return since GDB will reject it.
+    		
+    		// Until bug 256798 is fixed, the service tracker could be null
+    		if (getServicesTracker() == null) {
+    			// service is shutdown
+    			rm.setData(false);
+    			rm.done();
+    			return;
+    		}
+            MIStack stackService = getServicesTracker().getService(MIStack.class);
+            if (stackService != null) {
+            	// Check that the stack is at least two deep.
+            	stackService.getStackDepth(context, 2, new DataRequestMonitor<Integer>(getExecutor(), rm) {
+            		@Override
+            		public void handleCompleted() {
+            			if (isSuccess() && getData() == 1) {
+            				rm.setData(false);
+            				rm.done();
+            			} else {
+            				canReverseResume(context, rm);
+            			}
+            		}
+            	});
+            	return;
+            }
+    	}
+
 	   	canReverseResume(context, rm);		
 	}