prof/common/lookup.c

	lookup.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * 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 (c) 1998 by Sun Microsystems, Inc.
 * All rights reserved.
 */
#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Search routines for processing new-style mon.out files.
 */

#include "profv.h"

/*
 * Look up an address in a sorted-by-address namelist; this deals with
 * misses by mapping them to the next lower entry point.
 */
nltype *
nllookup(mod_info_t *module, Address address, Address *nxtsym_val)
{
    size_t      low = 0, middle, high = module->nfuncs - 1;
    nltype      *nl = module->nl;
    Address     keyval;

    /*
     * 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 < nl[low].value) {
        if (nxtsym_val) {
            *nxtsym_val = module->load_base +
                    (nl[low].value - module->txt_origin);
        }
        return (NULL);
    }

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

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

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

            return (&nl[middle]);
        }

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

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

/*
 * Look up a module's base address in a sorted list of pc-hits. Unlike
 * nllookup(), this deals with misses by mapping them to the next *higher*
 * pc-hit. This is so that we get into the module's first pc-hit rightaway,
 * even if the module's entry-point (load_base) itself is not a hit.
 */
Address *
locate(Address  *pclist, size_t nelem, Address keypc)
{
    size_t  low = 0, middle, high = nelem - 1;

    if (keypc <= pclist[low])
        return (pclist);

    if (keypc > pclist[high])
        return (NULL);

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

        if ((pclist[middle] < keypc) && (pclist[middle + 1] >= keypc))
            return (&pclist[middle + 1]);

        if (pclist[middle] >= keypc)
            high = middle;
        else
            low = middle + 1;
    }

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