anchor.diff:    }
   
     void traceCompilation(String methodName) {
  +    if (!enabled) return;
  +    traceActive =
  +        SSA_TRACE_FILTER == null || methodName.contains(SSA_TRACE_FILTER);
  +    if (!traceActive) return;
       tag("compilation", () {
         printProperty("name", methodName);
         printProperty("method", methodName);
  
positive.code: #import('../leg.dart');
  
  final bool GENERATE_SSA_TRACE = false;
  
  class HTracer extends HGraphVisitor implements Tracer {
    int indent = 0;
    final RandomAccessFile output;
    final bool enabled = GENERATE_SSA_TRACE;
  
    HTracer([String path = "dart.cfg"])
        : output = GENERATE_SSA_TRACE ? new File(path).openSync(FileMode.WRITE)
  
negative.code:   }
  
    void traceGraph(String name, HGraph graph) {
      if (!traceActive) return;
      tag("cfg", () {
        printProperty("name", name);
        visitDominatorTree(graph);
  