common/ctf/ctf_decl.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"

/*
 * CTF Declaration Stack
 *
 * In order to implement ctf_type_name(), we must convert a type graph back
 * into a C type declaration.  Unfortunately, a type graph represents a storage
 * class ordering of the type whereas a type declaration must obey the C rules
 * for operator precedence, and the two orderings are frequently in conflict.
 * For example, consider these CTF type graphs and their C declarations:
 *
 * CTF_K_POINTER -> CTF_K_FUNCTION -> CTF_K_INTEGER  : int (*)()
 * CTF_K_POINTER -> CTF_K_ARRAY -> CTF_K_INTEGER     : int (*)[]
 *
 * In each case, parentheses are used to raise operator * to higher lexical
 * precedence, so the string form of the C declaration cannot be constructed by
 * walking the type graph links and forming the string from left to right.
 *
 * The functions in this file build a set of stacks from the type graph nodes
 * corresponding to the C operator precedence levels in the appropriate order.
 * The code in ctf_type_name() can then iterate over the levels and nodes in
 * lexical precedence order and construct the final C declaration string.
 */

#include <ctf_impl.h>

void
ctf_decl_init(ctf_decl_t *cd, char *buf, size_t len)
{
    int i;

    bzero(cd, sizeof (ctf_decl_t));

    for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++)
        cd->cd_order[i] = CTF_PREC_BASE - 1;

    cd->cd_qualp = CTF_PREC_BASE;
    cd->cd_ordp = CTF_PREC_BASE;

    cd->cd_buf = buf;
    cd->cd_ptr = buf;
    cd->cd_end = buf + len;
}

void
ctf_decl_fini(ctf_decl_t *cd)
{
    ctf_decl_node_t *cdp, *ndp;
    int i;

    for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) {
        for (cdp = ctf_list_next(&cd->cd_nodes[i]);
            cdp != NULL; cdp = ndp) {
            ndp = ctf_list_next(cdp);
            ctf_free(cdp, sizeof (ctf_decl_node_t));
        }
    }
}

void
ctf_decl_push(ctf_decl_t *cd, ctf_file_t *fp, ctf_id_t type)
{
    ctf_decl_node_t *cdp;
    ctf_decl_prec_t prec;
    uint_t kind, n = 1;
    int is_qual = 0;

    const ctf_type_t *tp;
    ctf_arinfo_t ar;

    if ((tp = ctf_lookup_by_id(&fp, type)) == NULL) {
        cd->cd_err = fp->ctf_errno;
        return;
    }

    switch (kind = LCTF_INFO_KIND(fp, tp->ctt_info)) {
    case CTF_K_ARRAY:
        (void) ctf_array_info(fp, type, &ar);
        ctf_decl_push(cd, fp, ar.ctr_contents);
        n = ar.ctr_nelems;
        prec = CTF_PREC_ARRAY;
        break;

    case CTF_K_TYPEDEF:
        if (ctf_strptr(fp, tp->ctt_name)[0] == '\0') {
            ctf_decl_push(cd, fp, tp->ctt_type);
            return;
        }
        prec = CTF_PREC_BASE;
        break;

    case CTF_K_FUNCTION:
        ctf_decl_push(cd, fp, tp->ctt_type);
        prec = CTF_PREC_FUNCTION;
        break;

    case CTF_K_POINTER:
        ctf_decl_push(cd, fp, tp->ctt_type);
        prec = CTF_PREC_POINTER;
        break;

    case CTF_K_VOLATILE:
    case CTF_K_CONST:
    case CTF_K_RESTRICT:
        ctf_decl_push(cd, fp, tp->ctt_type);
        prec = cd->cd_qualp;
        is_qual++;
        break;

    default:
        prec = CTF_PREC_BASE;
    }

    if ((cdp = ctf_alloc(sizeof (ctf_decl_node_t))) == NULL) {
        cd->cd_err = EAGAIN;
        return;
    }

    cdp->cd_type = type;
    cdp->cd_kind = kind;
    cdp->cd_n = n;

    if (ctf_list_next(&cd->cd_nodes[prec]) == NULL)
        cd->cd_order[prec] = cd->cd_ordp++;

    /*
     * Reset cd_qualp to the highest precedence level that we've seen so
     * far that can be qualified (CTF_PREC_BASE or CTF_PREC_POINTER).
     */
    if (prec > cd->cd_qualp && prec < CTF_PREC_ARRAY)
        cd->cd_qualp = prec;

    /*
     * C array declarators are ordered inside out so prepend them.  Also by
     * convention qualifiers of base types precede the type specifier (e.g.
     * const int vs. int const) even though the two forms are equivalent.
     */
    if (kind == CTF_K_ARRAY || (is_qual && prec == CTF_PREC_BASE))
        ctf_list_prepend(&cd->cd_nodes[prec], cdp);
    else
        ctf_list_append(&cd->cd_nodes[prec], cdp);
}

/*PRINTFLIKE2*/
void
ctf_decl_sprintf(ctf_decl_t *cd, const char *format, ...)
{
    size_t len = (size_t)(cd->cd_end - cd->cd_ptr);
    va_list ap;
    size_t n;

    va_start(ap, format);
    n = vsnprintf(cd->cd_ptr, len, format, ap);
    va_end(ap);

    cd->cd_ptr += MIN(n, len);
    cd->cd_len += n;
}