code: private void runCustomPasses(CustomPassExecutionTime executionTime) {
      if (options.customPasses != null) {
        Tracer t = newTracer("runCustomPasses");
        try {
          for (CompilerPass p : options.customPasses.get(executionTime)) {
            process(p);
          }
        } finally {
          stopTracer(t, "runCustomPasses");
        }
      }
    }
docs: Runs custom passes that are designated to run at a particular time.