func emitMetaData() {
	if covProfileAlreadyEmitted {
		return
	}
	ml, err := prepareForMetaEmit()
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: coverage meta-data prep failed: %v\n", err)
		if os.Getenv("GOCOVERDEBUG") != "" {
			panic("meta-data write failure")
		}
	}
	if len(ml) == 0 {
		fmt.Fprintf(os.Stderr, "program not built with -cover\n")
		return
	}

	goCoverDir = os.Getenv("GOCOVERDIR")