4.3BSD-Reno/src/lib/csu.tahoe/mon.c

static	char *sccsid = "@(#)mon.c	2.0 (Tahoe) 5/7/84";

#define ARCDENSITY	5	/* density of routines */
#define MINARCS		50	/* minimum number of counters */
#define	HISTFRACTION	2	/* fraction of text space for histograms */


struct phdr {
	char *lpc;
	char *hpc;
	int ncnt;
};

struct cnt {
	char *pc;
	long ncall;
} *countbase;

static int cntrs = 0;
static int profiling = 3;
static char *s_sbuf;
static int s_bufsiz;
static int s_scale;
static char *s_lowpc;

int numctrs;

#define	MSG "No space for monitor buffer(s)\n"

monstartup(lowpc, highpc)
	char *lowpc;
	char *highpc;
{
	int monsize;
	char *buffer;
	int cntsiz;
	extern char *sbrk();
	extern char *minbrk;


	cntsiz = (highpc - lowpc) * ARCDENSITY / 100;
	if (cntsiz < MINARCS)
		cntsiz = MINARCS;
	monsize = (highpc - lowpc + HISTFRACTION - 1) / HISTFRACTION
		+ sizeof(struct phdr) + cntsiz * sizeof(struct cnt);
	monsize = (monsize + 1) & ~1;
	buffer = sbrk(monsize);
	if (buffer == (char *)-1) {
		write(2, MSG, sizeof(MSG));
		return;
	}
	minbrk = sbrk(0);
	monitor(lowpc, highpc, buffer, monsize, cntsiz);
}

mcount(cntpa)
	long **cntpa;
{
	register long **cntp;
	register char *selfpc;

	/*
	 * find the return address for mcount,
	 * and address of counter pointer
	 */
	selfpc = *((char **)&cntpa-3);	/* -8(fp) */
	cntp = cntpa;
	/*
	 * check that we aren't recursively invoked.
	 */
	if (profiling)
		goto out;
	profiling++;
	/*
	 * check that counter is allocated
	 */
	if (*cntp == 0) {
		/*
		 * check that a counter is available
		 */
		if (cntrs++ == numctrs)
			goto overflow;
		countbase->pc = selfpc;
		*cntp = &countbase->ncall;
		countbase++;
	}
	(**cntp)++;
	profiling--;
out:
	return;

overflow:
#   define	TOLIMIT	"mcount: counter overflow\n"
	write( 2 , TOLIMIT , sizeof( TOLIMIT ) );
	goto out;
}

monitor(lowpc, highpc, buf, bufsiz, cntsiz)
	char *lowpc, *highpc;
	char *buf;
	int bufsiz, cntsiz;
{
	register int o;
	struct phdr *php;
	static int ssiz;
	static char *sbuf;

	if (lowpc == 0) {
		moncontrol(0);
		o = creat("mon.out", 0666);
		write(o, sbuf, ssiz);
		close(o);
		return;
	}
	sbuf = buf;
	ssiz = bufsiz;
	php = (struct phdr *)&buf[0];
	php->lpc = lowpc;
	php->hpc = highpc;
	php->ncnt = cntsiz;
	numctrs = cntsiz;
	countbase = (struct cnt *)(buf + sizeof(struct phdr));
	o = sizeof(struct phdr) + cntsiz * sizeof(struct cnt);
	buf += o;
	bufsiz -= o;
	if (bufsiz <= 0)
		return;
	o = (highpc - lowpc);
	if(bufsiz < o)
		o = ((float) bufsiz / o) * 65536;
	else
		o = 65536;
	s_scale = o;
	s_sbuf = buf;
	s_bufsiz = bufsiz;
	s_lowpc = lowpc;
	moncontrol(1);
}

/*
 * Control profiling
 *	profiling is what mcount checks to see if
 *	all the data structures are ready.
 */
moncontrol(mode)
    int mode;
{
    if (mode) {
	/* start */
	profil(s_sbuf, s_bufsiz, s_lowpc, s_scale);
	profiling = 0;
    } else {
	/* stop */
	profil((char *)0, 0, 0, 0);
	profiling = 3;
    }
}