#include <stdio.h>

struct iwm_softc {
	unsigned sc_trace_depth;
};

struct iwm_trace_frame {
	struct iwm_softc *tf_softc;
	const char *tf_func;
};

static void
iwm_trace_enter(struct iwm_trace_frame *tf)
{
	struct iwm_softc *sc = tf->tf_softc;

	printf("%*.scall %s\n", 2*sc->sc_trace_depth, "", tf->tf_func);
	sc->sc_trace_depth++;
}

static void
iwm_trace_exit(struct iwm_trace_frame *tf)
{
	struct iwm_softc *sc = tf->tf_softc;

	sc->sc_trace_depth--;
	printf("%*.sreturn %s\n", 2*sc->sc_trace_depth, "", tf->tf_func);
}

#define	TRACE								      \
	struct iwm_trace_frame trace_frame				      \
		__attribute__((cleanup(iwm_trace_exit)))		      \
		= {							      \
	    .tf_softc = sc,						      \
	    .tf_func = __func__,					      \
	};								      \
	iwm_trace_enter(&trace_frame)

void
i(struct iwm_softc *sc)
{TRACE;
	printf("hello, i'm i\n");
}

void
g(struct iwm_softc *sc)
{TRACE;
	printf("hello, i'm g\n");
	i(sc);
}

void
h(struct iwm_softc *sc)
{TRACE;
	printf("hello, i'm h\n");
}

void
f(struct iwm_softc *sc)
{TRACE;
	printf("hello, i'm f\n");
	g(sc);
	h(sc);
}

int
main(void)
{
	struct iwm_softc sc = {0};

	f(&sc);
}