/*- * Copyright (c) 1983, 1992, 1993 *	The Regents of the University of California.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *	This product includes software developed by the University of *	California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */#if !defined(lint) && !defined(KERNEL) && defined(LIBC_SCCS)static char sccsid[] = "@(#)mcount.c	8.1 (Berkeley) 6/4/93";#endif#include <sys/param.h>#include <sys/gmon.h>/* * mcount is called on entry to each function compiled with the profiling * switch set.  _mcount(), which is declared in a machine-dependent way * with _MCOUNT_DECL, does the actual work and is either inlined into a * C routine or called by an assembly stub.  In any case, this magic is * taken care of by the MCOUNT definition in <machine/profile.h>. * * _mcount updates data structures that represent traversals of the * program's call graph edges.  frompc and selfpc are the return * address and function address that represents the given call graph edge. *  * Note: the original BSD code used the same variable (frompcindex) for * both frompcindex and frompc.  Any reasonable, modern compiler will * perform this optimization. */_MCOUNT_DECL(frompc, selfpc)	/* _mcount; may be static, inline, etc */	register u_long frompc, selfpc;{	register u_short *frompcindex;	register struct tostruct *top, *prevtop;	register struct gmonparam *p;	register long toindex;#ifdef KERNEL	register int s;#endif	p = &_gmonparam;	/*	 * check that we are profiling	 * and that we aren't recursively invoked.	 */	if (p->state != GMON_PROF_ON)		return;#ifdef KERNEL	MCOUNT_ENTER;#else	p->state = GMON_PROF_BUSY;#endif	/*	 * check that frompcindex is a reasonable pc value.	 * for example:	signal catchers get called from the stack,	 *		not from text space.  too bad.	 */	frompc -= p->lowpc;	if (frompc > p->textsize)		goto done;	frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))];	toindex = *frompcindex;	if (toindex == 0) {		/*		 *	first time traversing this arc		 */		toindex = ++p->tos[0].link;		if (toindex >= p->tolimit)			/* halt further profiling */			goto overflow;		*frompcindex = toindex;		top = &p->tos[toindex];		top->selfpc = selfpc;		top->count = 1;		top->link = 0;		goto done;	}	top = &p->tos[toindex];	if (top->selfpc == selfpc) {		/*		 * arc at front of chain; usual case.		 */		top->count++;		goto done;	}	/*	 * have to go looking down chain for it.	 * top points to what we are looking at,	 * prevtop points to previous top.	 * we know it is not at the head of the chain.	 */	for (; /* goto done */; ) {		if (top->link == 0) {			/*			 * top is end of the chain and none of the chain			 * had top->selfpc == selfpc.			 * so we allocate a new tostruct			 * and link it to the head of the chain.			 */			toindex = ++p->tos[0].link;			if (toindex >= p->tolimit)				goto overflow;			top = &p->tos[toindex];			top->selfpc = selfpc;			top->count = 1;			top->link = *frompcindex;			*frompcindex = toindex;			goto done;		}		/*		 * otherwise, check the next arc on the chain.		 */		prevtop = top;		top = &p->tos[top->link];		if (top->selfpc == selfpc) {			/*			 * there it is.			 * increment its count			 * move it to the head of the chain.			 */			top->count++;			toindex = prevtop->link;			prevtop->link = top->link;			top->link = *frompcindex;			*frompcindex = toindex;			goto done;		}			}done:#ifdef KERNEL	MCOUNT_EXIT;#else	p->state = GMON_PROF_ON;#endif	return;overflow:	p->state = GMON_PROF_ERROR;#ifdef KERNEL	MCOUNT_EXIT;#endif	return;}/* * Actual definition of mcount function.  Defined in <machine/profile.h>, * which is included by <sys/gmon.h>. */MCOUNT