gprof/common/lookup.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "gprof.h"

/*
 * look up an address in a sorted-by-address namelist
 * this deals with misses by mapping them to the next lower
 * entry point.
 */
static   int    searchmsg = 0; /* Emit the diagnostic only once */

nltype *
nllookup(mod_info_t *module, pctype address, pctype *nxtsym)
{
    size_t  low = 0, middle, high = module->nname - 1;
    pctype  keyval;
    nltype  *mnl = module->nl;

    /*
     * If this is the program executable in which we are looking up
     * a symbol, then the actual load address will be the same as the
     * address specified in the ELF file. For shared objects, the
     * load address may differ from what is specified in the file. In
     * this case, we may need to look for a different value altogether.
     */
    keyval = module->txt_origin + (address - module->load_base);

    if (keyval < mnl[low].value) {
        if (nxtsym) {
            *nxtsym = module->load_base +
                    (mnl[low].value - module->txt_origin);
        }
        return (NULL);
    }

    if (keyval >= mnl[high].value) {
        if (nxtsym)
            *nxtsym = module->load_end;
        return (&mnl[high]);
    }

    while (low != high) {
        middle = (high + low) >> 1;

        if (mnl[middle].value <= keyval &&
                        mnl[middle + 1].value > keyval) {
            if (nxtsym) {
                *nxtsym = module->load_base +
                            (mnl[middle + 1].value -
                            module->txt_origin);
            }
            return (&mnl[middle]);
        }

        if (mnl[middle].value > keyval) {
            high = middle;
        } else {
            low = middle + 1;
        }
    }

    if (searchmsg++ == 0)
        (void) fprintf(stderr, "[nllookup] binary search fails???\n");

    /* must never reach here! */
    return (0);
}

arctype *
arclookup(nltype *parentp, nltype *childp)
{
    arctype *arcp;

    if (parentp == 0 || childp == 0) {
        (void) fprintf(stderr,
            "[arclookup] parentp == 0 || childp == 0\n");
        return (0);
    }
#ifdef DEBUG
    if (debug & LOOKUPDEBUG) {
        (void) printf("[arclookup] parent %s child %s\n",
            parentp->name, childp->name);
    }
#endif /* DEBUG */

    for (arcp = parentp->children; arcp; arcp = arcp->arc_childlist) {
#ifdef DEBUG
        if (debug & LOOKUPDEBUG) {
            (void) printf(
                "[arclookup]\t arc_parent %s arc_child %s\n",
                arcp->arc_parentp->name,
                arcp->arc_childp->name);
        }
#endif /* DEBUG */
        if (arcp->arc_childp == childp) {
            return (arcp);
        }
    }
    return (0);
}