anchor.diff:  
         final line = format(ctx, opcode, operands);
   
  -      var fields = null;
  -
  -      if (ir.profile != null && ir.profile.hirTicks.containsKey(instr)) {
  -        final ticks = ir.profile.hirTicks[instr];
  -        fields = {
  -          "ticks": new Element.tag("b")
  -            ..appendText("${ticks.toStringAsFixed(2)}")
  -            ..style.color = "${brewer.colorFor(ticks, 0, ir.profile.maxHirTicks)}"
  -        };
  -      }
  -
  -      var ln = add(gutter, line, id: id, fields: fields);
  +      final ln = add(gutter, line, id: id, fields: fieldsFor(instr));
         ln.gutter.parentNode.classes.add("${ctx.ns}-gutter");
         ln.text.parentNode.classes.add("${ctx.ns}-line");
         return ln;
  
positive.code:       new SpanElement()..append(formatOpcode(ctx, opcode))
                         ..appendText(" ")
                         ..append(new SpanElement()..nodes.addAll(operands.map(ctx.format)));
  
      addEx(ctx, instr) {
        // id, opcode, operands
  
negative.code:                     ..append(makeBlockRef(instr.true_successor))
                      ..appendText(", ")
                      ..append(makeBlockRef(instr.false_successor))
                      ..appendText(")"), fields: fieldsFor(instr));
        ln.gutter.parentNode.classes.add("${ctx.ns}-gutter");
        ln.text.parentNode.classes.add("${ctx.ns}-line");
      }
  