示例#1
0
文件: expr.c 项目: Acidburn0zzz/yasm
static yasm_expr *
expr_expand_equ(yasm_expr *e, yasm__exprhead *eh)
{
    int i;
    yasm__exprentry ee;

    /* traverse terms */
    for (i=0; i<e->numterms; i++) {
        const yasm_expr *equ_expr;

        /* Expand equ's. */
        if (e->terms[i].type == YASM_EXPR_SYM &&
            (equ_expr = yasm_symrec_get_equ(e->terms[i].data.sym))) {
            yasm__exprentry *np;

            /* Check for circular reference */
            SLIST_FOREACH(np, eh, next) {
                if (np->e == equ_expr) {
                    yasm_error_set(YASM_ERROR_TOO_COMPLEX,
                                   N_("circular reference detected"));
                    return e;
                }
            }

            e->terms[i].type = YASM_EXPR_EXPR;
            e->terms[i].data.expn = yasm_expr_copy(equ_expr);

            /* Remember we saw this equ and recurse */
            ee.e = equ_expr;
            SLIST_INSERT_HEAD(eh, &ee, next);
            e->terms[i].data.expn = expr_expand_equ(e->terms[i].data.expn, eh);
            SLIST_REMOVE_HEAD(eh, next);
        } else if (e->terms[i].type == YASM_EXPR_EXPR)
示例#2
0
static int
value_finalize_scan(yasm_value *value, yasm_expr *e,
                    /*@null@*/ yasm_bytecode *expr_precbc, int ssym_not_ok)
{
    int i;
    /*@dependent@*/ yasm_section *sect;
    /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc;

    unsigned long shamt;    /* for SHR */

    /* Yes, this has a maximum upper bound on 32 terms, based on an
     * "insane number of terms" (and ease of implementation) WAG.
     * The right way to do this would be a stack-based alloca, but that's
     * not ISO C.  We really don't want to malloc here as this function is
     * hit a lot!
     *
     * This is a bitmask to keep things small, as this is a recursive
     * routine and we don't want to eat up stack space.
     */
    unsigned long used;     /* for ADD */

    /* Thanks to this running after a simplify, we don't need to iterate
     * down through IDENTs or handle SUB.
     *
     * We scan for a single symrec, gathering info along the way.  After
     * we've found the symrec, we keep scanning but error if we find
     * another one.  We pull out the single symrec and any legal operations
     * performed on it.
     *
     * Also, if we find a float anywhere, we don't allow mixing of a single
     * symrec with it.
     */
    switch (e->op) {
        case YASM_EXPR_ADD:
            /* Okay for single symrec anywhere in expr.
             * Check for single symrec anywhere.
             * Handle symrec-symrec by checking for (-1*symrec)
             * and symrec term pairs (where both symrecs are in the same
             * segment).
             */
            if (e->numterms > 32)
                yasm__fatal(N_("expression on line %d has too many add terms;"
                               " internal limit of 32"), e->line);

            used = 0;

            for (i=0; i<e->numterms; i++) {
                int j;
                yasm_expr *sube;
                yasm_intnum *intn;
                yasm_symrec *sym;
                /*@dependent@*/ yasm_section *sect2;
                /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc2;

                /* First look for an (-1*symrec) term */
                if (e->terms[i].type != YASM_EXPR_EXPR)
                    continue;
                sube = e->terms[i].data.expn;

                if (sube->op != YASM_EXPR_MUL || sube->numterms != 2) {
                    /* recurse instead */
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                if (sube->terms[0].type == YASM_EXPR_INT &&
                    sube->terms[1].type == YASM_EXPR_SYM) {
                    intn = sube->terms[0].data.intn;
                    sym = sube->terms[1].data.sym;
                } else if (sube->terms[0].type == YASM_EXPR_SYM &&
                           sube->terms[1].type == YASM_EXPR_INT) {
                    sym = sube->terms[0].data.sym;
                    intn = sube->terms[1].data.intn;
                } else {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                if (!yasm_intnum_is_neg1(intn)) {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                /* Look for the same symrec term; even if both are external,
                 * they should cancel out.
                 */
                for (j=0; j<e->numterms; j++) {
                    if (e->terms[j].type == YASM_EXPR_SYM
                        && e->terms[j].data.sym == sym
                        && (used & (1<<j)) == 0) {
                        /* Mark as used */
                        used |= 1<<j;

                        /* Replace both symrec portions with 0 */
                        yasm_expr_destroy(sube);
                        e->terms[i].type = YASM_EXPR_INT;
                        e->terms[i].data.intn = yasm_intnum_create_uint(0);
                        e->terms[j].type = YASM_EXPR_INT;
                        e->terms[j].data.intn = yasm_intnum_create_uint(0);

                        break;  /* stop looking */
                    }
                }
                if (j != e->numterms)
                    continue;

                if (!yasm_symrec_get_label(sym, &precbc)) {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }
                sect2 = yasm_bc_get_section(precbc);

                /* Now look for a unused symrec term in the same segment */
                for (j=0; j<e->numterms; j++) {
                    if (e->terms[j].type == YASM_EXPR_SYM
                        && yasm_symrec_get_label(e->terms[j].data.sym,
                                                 &precbc2)
                        && (sect = yasm_bc_get_section(precbc2))
                        && sect == sect2
                        && (used & (1<<j)) == 0) {
                        /* Mark as used */
                        used |= 1<<j;
                        break;  /* stop looking */
                    }
                }

                /* We didn't match in the same segment.  If the
                 * -1*symrec is actually -1*curpos, we can match
                 * unused symrec terms in other segments and generate
                 * a curpos-relative reloc.
                 *
                 * Similarly, handle -1*symrec in other segment via the
                 * following transformation:
                 * other-this = (other-.)+(.-this)
                 * We can only do this transformation if "this" is in
                 * this expr's segment.
                 *
                 * Don't do this if we've already become curpos-relative.
                 * The unmatched symrec will be caught below.
                 */
                if (j == e->numterms && !value->curpos_rel
                    && (yasm_symrec_is_curpos(sym)
                        || (expr_precbc
                            && sect2 == yasm_bc_get_section(expr_precbc)))) {
                    for (j=0; j<e->numterms; j++) {
                        if (e->terms[j].type == YASM_EXPR_SYM
                            && !yasm_symrec_get_equ(e->terms[j].data.sym)
                            && !yasm_symrec_is_special(e->terms[j].data.sym)
                            && (used & (1<<j)) == 0) {
                            /* Mark as used */
                            used |= 1<<j;
                            /* Mark value as curpos-relative */
                            if (value->rel || ssym_not_ok)
                                return 1;
                            value->rel = e->terms[j].data.sym;
                            value->curpos_rel = 1;
                            if (yasm_symrec_is_curpos(sym)) {
                                /* Replace both symrec portions with 0 */
                                yasm_expr_destroy(sube);
                                e->terms[i].type = YASM_EXPR_INT;
                                e->terms[i].data.intn =
                                    yasm_intnum_create_uint(0);
                                e->terms[j].type = YASM_EXPR_INT;
                                e->terms[j].data.intn =
                                    yasm_intnum_create_uint(0);
                            } else {
                                /* Replace positive portion with curpos */
                                yasm_object *object =
                                    yasm_section_get_object(sect2);
                                yasm_symtab *symtab = object->symtab;
                                e->terms[j].data.sym =
                                    yasm_symtab_define_curpos
                                    (symtab, ".", expr_precbc, e->line);
                            }
                            break;      /* stop looking */
                        }
                    }
                }


                if (j == e->numterms)
                    return 1;   /* We didn't find a match! */
            }

            /* Look for unmatched symrecs.  If we've already found one or
             * we don't WANT to find one, error out.
             */
            for (i=0; i<e->numterms; i++) {
                if (e->terms[i].type == YASM_EXPR_SYM
                    && (used & (1<<i)) == 0) {
                    if (value->rel || ssym_not_ok)
                        return 1;
                    value->rel = e->terms[i].data.sym;
                    /* and replace with 0 */
                    e->terms[i].type = YASM_EXPR_INT;
                    e->terms[i].data.intn = yasm_intnum_create_uint(0);
                }
            }
            break;
        case YASM_EXPR_SHR:
            /* Okay for single symrec in LHS and constant on RHS.
             * Single symrecs are not okay on RHS.
             * If RHS is non-constant, don't allow single symrec on LHS.
             * XXX: should rshift be an expr instead??
             */

            /* Check for single sym on LHS */
            if (e->terms[0].type != YASM_EXPR_SYM)
                break;

            /* If we already have a sym, we can't take another one */
            if (value->rel || ssym_not_ok)
                return 1;

            /* RHS must be a positive integer */
            if (e->terms[1].type != YASM_EXPR_INT)
                return 1;       /* can't shift sym by non-constant integer */
            shamt = yasm_intnum_get_uint(e->terms[1].data.intn);
            if ((shamt + value->rshift) > YASM_VALUE_RSHIFT_MAX)
                return 1;       /* total shift would be too large */

            /* Update value */
            value->rshift += shamt;
            value->rel = e->terms[0].data.sym;

            /* Replace symbol with 0 */
            e->terms[0].type = YASM_EXPR_INT;
            e->terms[0].data.intn = yasm_intnum_create_uint(0);

            /* Just leave SHR in place */
            break;
        case YASM_EXPR_SEG:
            /* Okay for single symrec (can only be done once).
             * Not okay for anything BUT a single symrec as an immediate
             * child.
             */
            if (e->terms[0].type != YASM_EXPR_SYM)
                return 1;

            if (value->seg_of)
                return 1;       /* multiple SEG not legal */
            value->seg_of = 1;

            if (value->rel || ssym_not_ok)
                return 1;       /* got a relative portion somewhere else? */
            value->rel = e->terms[0].data.sym;

            /* replace with ident'ed 0 */
            e->op = YASM_EXPR_IDENT;
            e->terms[0].type = YASM_EXPR_INT;
            e->terms[0].data.intn = yasm_intnum_create_uint(0);
            break;
        case YASM_EXPR_WRT:
            /* Okay for single symrec in LHS and either a register or single
             * symrec (as an immediate child) on RHS.
             * If a single symrec on RHS, can only be done once.
             * WRT reg is left in expr for arch to look at.
             */

            /* Handle RHS */
            switch (e->terms[1].type) {
                case YASM_EXPR_SYM:
                    if (value->wrt)
                        return 1;
                    value->wrt = e->terms[1].data.sym;
                    /* and drop the WRT portion */
                    e->op = YASM_EXPR_IDENT;
                    e->numterms = 1;
                    break;
                case YASM_EXPR_REG:
                    break;  /* ignore */
                default:
                    return 1;
            }

            /* Handle LHS */
            switch (e->terms[0].type) {
                case YASM_EXPR_SYM:
                    if (value->rel || ssym_not_ok)
                        return 1;
                    value->rel = e->terms[0].data.sym;
                    /* and replace with 0 */
                    e->terms[0].type = YASM_EXPR_INT;
                    e->terms[0].data.intn = yasm_intnum_create_uint(0);
                    break;
                case YASM_EXPR_EXPR:
                    /* recurse */
                    return value_finalize_scan(value, e->terms[0].data.expn,
                                               expr_precbc, ssym_not_ok);
                default:
                    break;  /* ignore */
            }

            break;
        default:
            /* Single symrec not allowed anywhere */
            for (i=0; i<e->numterms; i++) {
                switch (e->terms[i].type) {
                    case YASM_EXPR_SYM:
                        return 1;
                    case YASM_EXPR_EXPR:
                        /* recurse */
                        return value_finalize_scan(value,
                                                   e->terms[i].data.expn,
                                                   expr_precbc, 1);
                    default:
                        break;
                }
            }
            break;
    }

    return 0;
}
示例#3
0
static int
xdf_objfmt_output_sym(yasm_symrec *sym, /*@null@*/ void *d)
{
    /*@null@*/ xdf_objfmt_output_info *info = (xdf_objfmt_output_info *)d;
    yasm_sym_vis vis = yasm_symrec_get_visibility(sym);

    assert(info != NULL);

    if (info->all_syms || vis != YASM_SYM_LOCAL) {
        /*@only@*/ char *name = yasm_symrec_get_global_name(sym, info->object);
        const yasm_expr *equ_val;
        const yasm_intnum *intn;
        size_t len = strlen(name);
        unsigned long value = 0;
        long scnum = -3;        /* -3 = debugging symbol */
        /*@dependent@*/ /*@null@*/ yasm_section *sect;
        /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc;
        unsigned long flags = 0;
        unsigned char *localbuf;

        if (vis & YASM_SYM_GLOBAL)
            flags = XDF_SYM_GLOBAL;

        /* Look at symrec for value/scnum/etc. */
        if (yasm_symrec_get_label(sym, &precbc)) {
            if (precbc)
                sect = yasm_bc_get_section(precbc);
            else
                sect = NULL;
            /* it's a label: get value and offset.
             * If there is not a section, leave as debugging symbol.
             */
            if (sect) {
                /*@dependent@*/ /*@null@*/ xdf_section_data *csectd;
                csectd = yasm_section_get_data(sect, &xdf_section_data_cb);
                if (csectd)
                    scnum = csectd->scnum;
                else
                    yasm_internal_error(N_("didn't understand section"));
                if (precbc)
                    value += yasm_bc_next_offset(precbc);
            }
        } else if ((equ_val = yasm_symrec_get_equ(sym))) {
            yasm_expr *equ_val_copy = yasm_expr_copy(equ_val);
            intn = yasm_expr_get_intnum(&equ_val_copy, 1);
            if (!intn) {
                if (vis & YASM_SYM_GLOBAL) {
                    yasm_error_set(YASM_ERROR_NOT_CONSTANT,
                        N_("global EQU value not an integer expression"));
                    yasm_errwarn_propagate(info->errwarns, equ_val->line);
                }
            } else
                value = yasm_intnum_get_uint(intn);
            yasm_expr_destroy(equ_val_copy);

            flags |= XDF_SYM_EQU;
            scnum = -2;     /* -2 = absolute symbol */
        } else {
            if (vis & YASM_SYM_EXTERN) {
                flags = XDF_SYM_EXTERN;
                scnum = -1;
            }
        }

        localbuf = info->buf;
        YASM_WRITE_32_L(localbuf, scnum);       /* section number */
        YASM_WRITE_32_L(localbuf, value);       /* value */
        YASM_WRITE_32_L(localbuf, info->strtab_offset);
        info->strtab_offset += (unsigned long)(len+1);
        YASM_WRITE_32_L(localbuf, flags);       /* flags */
        fwrite(info->buf, 16, 1, info->f);
        yasm_xfree(name);
    }
    return 0;
}