xdf-objfmt.c

/*
 * Extended Dynamic Object format
 *
 *  Copyright (C) 2004-2007  Peter Johnson
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER 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 AUTHOR OR OTHER 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.
 */
#include <util.h>
/*@unused@*/ RCSID("$Id$");

#include <libyasm.h>


#define REGULAR_OUTBUF_SIZE     1024

#define XDF_MAGIC       0x87654322

#define XDF_SYM_EXTERN  1
#define XDF_SYM_GLOBAL  2
#define XDF_SYM_EQU     4

typedef struct xdf_reloc {
    yasm_reloc reloc;
    /*@null@*/ yasm_symrec *base;   /* base symbol (for WRT) */
    enum {
        XDF_RELOC_REL = 1,          /* relative to segment */
        XDF_RELOC_WRT = 2,          /* relative to symbol */
        XDF_RELOC_RIP = 4,          /* RIP-relative */
        XDF_RELOC_SEG = 8           /* segment containing symbol */
    } type;                         /* type of relocation */
    enum {
        XDF_RELOC_8  = 1,         
        XDF_RELOC_16 = 2,      
        XDF_RELOC_32 = 4,      
        XDF_RELOC_64 = 8
    } size;                         /* size of relocation */
    unsigned int shift;             /* relocation shift (0,4,8,16,24,32) */
} xdf_reloc;

typedef struct xdf_section_data {
    /*@dependent@*/ yasm_symrec *sym;   /* symbol created for this section */
    yasm_intnum *addr;      /* starting memory address */
    yasm_intnum *vaddr;     /* starting virtual address */
    long scnum;             /* section number (0=first section) */
    enum {
        XDF_SECT_ABSOLUTE = 0x01,
        XDF_SECT_FLAT = 0x02,
        XDF_SECT_BSS = 0x04,
        XDF_SECT_EQU = 0x08,
        XDF_SECT_USE_16 = 0x10,
        XDF_SECT_USE_32 = 0x20,
        XDF_SECT_USE_64 = 0x40
    } flags;                /* section flags */
    unsigned long scnptr;   /* file ptr to raw data */
    unsigned long size;     /* size of raw data (section data) in bytes */
    unsigned long relptr;   /* file ptr to relocation */
    unsigned long nreloc;   /* number of relocation entries >64k -> error */
} xdf_section_data;

typedef struct xdf_symrec_data {
    unsigned long index;                /* assigned XDF symbol table index */
} xdf_symrec_data;

typedef struct yasm_objfmt_xdf {
    yasm_objfmt_base objfmt;                /* base structure */

    long parse_scnum;               /* sect numbering in parser */
} yasm_objfmt_xdf;

typedef struct xdf_objfmt_output_info {
    yasm_object *object;
    yasm_objfmt_xdf *objfmt_xdf;
    yasm_errwarns *errwarns;
    /*@dependent@*/ FILE *f;
    /*@only@*/ unsigned char *buf;
    yasm_section *sect;
    /*@dependent@*/ xdf_section_data *xsd;

    unsigned long indx;             /* current symbol index */
    int all_syms;                   /* outputting all symbols? */
    unsigned long strtab_offset;    /* current string table offset */
} xdf_objfmt_output_info;

static void xdf_section_data_destroy(/*@only@*/ void *d);
static void xdf_section_data_print(void *data, FILE *f, int indent_level);

static const yasm_assoc_data_callback xdf_section_data_cb = {
    xdf_section_data_destroy,
    xdf_section_data_print
};

static void xdf_symrec_data_destroy(/*@only@*/ void *d);
static void xdf_symrec_data_print(void *data, FILE *f, int indent_level);

static const yasm_assoc_data_callback xdf_symrec_data_cb = {
    xdf_symrec_data_destroy,
    xdf_symrec_data_print
};

yasm_objfmt_module yasm_xdf_LTX_objfmt;


static yasm_objfmt *
xdf_objfmt_create(yasm_object *object)
{
    yasm_objfmt_xdf *objfmt_xdf = yasm_xmalloc(sizeof(yasm_objfmt_xdf));

    /* Only support x86 arch */
    if (yasm__strcasecmp(yasm_arch_keyword(object->arch), "x86") != 0) {
        yasm_xfree(objfmt_xdf);
        return NULL;
    }

    /* Support x86 and amd64 machines of x86 arch */
    if (yasm__strcasecmp(yasm_arch_get_machine(object->arch), "x86") &&
        yasm__strcasecmp(yasm_arch_get_machine(object->arch), "amd64")) {
        yasm_xfree(objfmt_xdf);
        return NULL;
    }

    objfmt_xdf->parse_scnum = 0;    /* section numbering starts at 0 */

    objfmt_xdf->objfmt.module = &yasm_xdf_LTX_objfmt;

    return (yasm_objfmt *)objfmt_xdf;
}

static int
xdf_objfmt_output_value(yasm_value *value, unsigned char *buf,
                        unsigned int destsize, unsigned long offset,
                        yasm_bytecode *bc, int warn, /*@null@*/ void *d)
{
    /*@null@*/ xdf_objfmt_output_info *info = (xdf_objfmt_output_info *)d;
    yasm_objfmt_xdf *objfmt_xdf;
    /*@dependent@*/ /*@null@*/ yasm_intnum *intn;
    unsigned long intn_minus;
    int retval;
    unsigned int valsize = value->size;

    assert(info != NULL);
    objfmt_xdf = info->objfmt_xdf;

    if (value->abs)
        value->abs = yasm_expr_simplify(value->abs, 1);

    /* Try to output constant and PC-relative section-local first.
     * Note this does NOT output any value with a SEG, WRT, external,
     * cross-section, or non-PC-relative reference (those are handled below).
     */
    switch (yasm_value_output_basic(value, buf, destsize, bc, warn,
                                    info->object->arch)) {
        case -1:
            return 1;
        case 0:
            break;
        default:
            return 0;
    }

    if (value->section_rel) {
        yasm_error_set(YASM_ERROR_TOO_COMPLEX,
                       N_("xdf: relocation too complex"));
        return 1;
    }

    intn_minus = 0;
    if (value->rel) {
        xdf_reloc *reloc;

        reloc = yasm_xmalloc(sizeof(xdf_reloc));
        reloc->reloc.addr = yasm_intnum_create_uint(bc->offset + offset);
        reloc->reloc.sym = value->rel;
        reloc->base = NULL;
        reloc->size = valsize/8;
        reloc->shift = value->rshift;

        if (value->seg_of)
            reloc->type = XDF_RELOC_SEG;
        else if (value->wrt) {
            reloc->base = value->wrt;
            reloc->type = XDF_RELOC_WRT;
        } else if (value->curpos_rel) {
            reloc->type = XDF_RELOC_RIP;
            /* Adjust to start of section, so subtract out the bytecode
             * offset.
             */
            intn_minus = bc->offset;
        } else
            reloc->type = XDF_RELOC_REL;
        info->xsd->nreloc++;
        yasm_section_add_reloc(info->sect, (yasm_reloc *)reloc, yasm_xfree);
    }

    if (intn_minus > 0) {
        intn = yasm_intnum_create_uint(intn_minus);
        yasm_intnum_calc(intn, YASM_EXPR_NEG, NULL);
    } else
        intn = yasm_intnum_create_uint(0);

    if (value->abs) {
        yasm_intnum *intn2 = yasm_expr_get_intnum(&value->abs, 0);
        if (!intn2) {
            yasm_error_set(YASM_ERROR_TOO_COMPLEX,
                           N_("xdf: relocation too complex"));
            yasm_intnum_destroy(intn);
            return 1;
        }
        yasm_intnum_calc(intn, YASM_EXPR_ADD, intn2);
    }

    retval = yasm_arch_intnum_tobytes(info->object->arch, intn, buf, destsize,
                                      valsize, 0, bc, warn);
    yasm_intnum_destroy(intn);
    return retval;
}

static int
xdf_objfmt_output_bytecode(yasm_bytecode *bc, /*@null@*/ void *d)
{
    /*@null@*/ xdf_objfmt_output_info *info = (xdf_objfmt_output_info *)d;
    /*@null@*/ /*@only@*/ unsigned char *bigbuf;
    unsigned long size = REGULAR_OUTBUF_SIZE;
    int gap;

    assert(info != NULL);

    bigbuf = yasm_bc_tobytes(bc, info->buf, &size, &gap, info,
                             xdf_objfmt_output_value, NULL);

    /* Don't bother doing anything else if size ended up being 0. */
    if (size == 0) {
        if (bigbuf)
            yasm_xfree(bigbuf);
        return 0;
    }

    info->xsd->size += size;

    /* Warn that gaps are converted to 0 and write out the 0's. */
    if (gap) {
        unsigned long left;
        yasm_warn_set(YASM_WARN_UNINIT_CONTENTS,
                      N_("uninitialized space: zeroing"));
        /* Write out in chunks */
        memset(info->buf, 0, REGULAR_OUTBUF_SIZE);
        left = size;
        while (left > REGULAR_OUTBUF_SIZE) {
            fwrite(info->buf, REGULAR_OUTBUF_SIZE, 1, info->f);
            left -= REGULAR_OUTBUF_SIZE;
        }
        fwrite(info->buf, left, 1, info->f);
    } else {
        /* Output buf (or bigbuf if non-NULL) to file */
        fwrite(bigbuf ? bigbuf : info->buf, (size_t)size, 1, info->f);
    }

    /* If bigbuf was allocated, free it */
    if (bigbuf)
        yasm_xfree(bigbuf);

    return 0;
}

static int
xdf_objfmt_output_section(yasm_section *sect, /*@null@*/ void *d)
{
    /*@null@*/ xdf_objfmt_output_info *info = (xdf_objfmt_output_info *)d;
    /*@dependent@*/ /*@null@*/ xdf_section_data *xsd;
    long pos;
    xdf_reloc *reloc;

    assert(info != NULL);
    xsd = yasm_section_get_data(sect, &xdf_section_data_cb);
    assert(xsd != NULL);

    if (xsd->flags & XDF_SECT_BSS) {
        /* Don't output BSS sections.
         * TODO: Check for non-reserve bytecodes?
         */
        pos = 0;    /* position = 0 because it's not in the file */
        xsd->size = yasm_bc_next_offset(yasm_section_bcs_last(sect));
    } else {
        pos = ftell(info->f);
        if (pos == -1) {
            yasm__fatal(N_("could not get file position on output file"));
            /*@notreached@*/
            return 1;
        }

        info->sect = sect;
        info->xsd = xsd;
        yasm_section_bcs_traverse(sect, info->errwarns, info,
                                  xdf_objfmt_output_bytecode);

        /* Sanity check final section size */
        if (xsd->size != yasm_bc_next_offset(yasm_section_bcs_last(sect)))
            yasm_internal_error(
                N_("xdf: section computed size did not match actual size"));
    }

    /* Empty?  Go on to next section */
    if (xsd->size == 0)
        return 0;

    xsd->scnptr = (unsigned long)pos;

    /* No relocations to output?  Go on to next section */
    if (xsd->nreloc == 0)
        return 0;

    pos = ftell(info->f);
    if (pos == -1) {
        yasm__fatal(N_("could not get file position on output file"));
        /*@notreached@*/
        return 1;
    }
    xsd->relptr = (unsigned long)pos;

    reloc = (xdf_reloc *)yasm_section_relocs_first(sect);
    while (reloc) {
        unsigned char *localbuf = info->buf;
        /*@null@*/ xdf_symrec_data *xsymd;

        xsymd = yasm_symrec_get_data(reloc->reloc.sym, &xdf_symrec_data_cb);
        if (!xsymd)
            yasm_internal_error(
                N_("xdf: no symbol data for relocated symbol"));

        yasm_intnum_get_sized(reloc->reloc.addr, localbuf, 4, 32, 0, 0, 0);
        localbuf += 4;                          /* address of relocation */
        YASM_WRITE_32_L(localbuf, xsymd->index);    /* relocated symbol */
        if (reloc->base) {
            xsymd = yasm_symrec_get_data(reloc->base, &xdf_symrec_data_cb);
            if (!xsymd)
                yasm_internal_error(
                    N_("xdf: no symbol data for relocated base symbol"));
            YASM_WRITE_32_L(localbuf, xsymd->index); /* base symbol */
        } else {
            if (reloc->type == XDF_RELOC_WRT)
                yasm_internal_error(
                    N_("xdf: no base symbol for WRT relocation"));
            YASM_WRITE_32_L(localbuf, 0);           /* no base symbol */
        }
        YASM_WRITE_8(localbuf, reloc->type);        /* type of relocation */
        YASM_WRITE_8(localbuf, reloc->size);        /* size of relocation */
        YASM_WRITE_8(localbuf, reloc->shift);       /* relocation shift */
        YASM_WRITE_8(localbuf, 0);                  /* flags */
        fwrite(info->buf, 16, 1, info->f);

        reloc = (xdf_reloc *)yasm_section_reloc_next((yasm_reloc *)reloc);
    }

    return 0;
}

static int
xdf_objfmt_output_secthead(yasm_section *sect, /*@null@*/ void *d)
{
    /*@null@*/ xdf_objfmt_output_info *info = (xdf_objfmt_output_info *)d;
    yasm_objfmt_xdf *objfmt_xdf;
    /*@dependent@*/ /*@null@*/ xdf_section_data *xsd;
    /*@null@*/ xdf_symrec_data *xsymd;
    unsigned char *localbuf;

    assert(info != NULL);
    objfmt_xdf = info->objfmt_xdf;
    xsd = yasm_section_get_data(sect, &xdf_section_data_cb);
    assert(xsd != NULL);

    localbuf = info->buf;
    xsymd = yasm_symrec_get_data(xsd->sym, &xdf_symrec_data_cb);
    assert(xsymd != NULL);

    YASM_WRITE_32_L(localbuf, xsymd->index);    /* section name symbol */
    if (xsd->addr) {
        yasm_intnum_get_sized(xsd->addr, localbuf, 8, 64, 0, 0, 0);
        localbuf += 8;                          /* physical address */
    } else {
        YASM_WRITE_32_L(localbuf, 0);
        YASM_WRITE_32_L(localbuf, 0);
    }
    if (xsd->vaddr) {
        yasm_intnum_get_sized(xsd->vaddr, localbuf, 8, 64, 0, 0, 0);
        localbuf += 8;                          /* virtual address */
    } else if (xsd->addr) {
        yasm_intnum_get_sized(xsd->addr, localbuf, 8, 64, 0, 0, 0);
        localbuf += 8;                          /* VA=PA */
    } else {
        YASM_WRITE_32_L(localbuf, 0);
        YASM_WRITE_32_L(localbuf, 0);
    }
    YASM_WRITE_16_L(localbuf, yasm_section_get_align(sect)); /* alignment */
    YASM_WRITE_16_L(localbuf, xsd->flags);      /* flags */
    YASM_WRITE_32_L(localbuf, xsd->scnptr);     /* file ptr to data */
    YASM_WRITE_32_L(localbuf, xsd->size);       /* section size */
    YASM_WRITE_32_L(localbuf, xsd->relptr);     /* file ptr to relocs */
    YASM_WRITE_32_L(localbuf, xsd->nreloc); /* num of relocation entries */
    fwrite(info->buf, 40, 1, info->f);

    return 0;
}

static int
xdf_objfmt_count_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 (vis & YASM_SYM_COMMON) {
        yasm_error_set(YASM_ERROR_GENERAL,
            N_("XDF object format does not support common variables"));
        yasm_errwarn_propagate(info->errwarns, yasm_symrec_get_decl_line(sym));
        return 0;
    }
    if (info->all_syms ||
        (vis != YASM_SYM_LOCAL && !(vis & YASM_SYM_DLOCAL))) {
        /* Save index in symrec data */
        xdf_symrec_data *sym_data = yasm_xmalloc(sizeof(xdf_symrec_data));
        sym_data->index = info->indx;
        yasm_symrec_add_data(sym, &xdf_symrec_data_cb, sym_data);

        info->indx++;
    }
    return 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;
}

static int
xdf_objfmt_output_str(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);
        size_t len = strlen(name);
        fwrite(name, len+1, 1, info->f);
        yasm_xfree(name);
    }
    return 0;
}

static void
xdf_objfmt_output(yasm_object *object, FILE *f, int all_syms,
                  yasm_errwarns *errwarns)
{
    yasm_objfmt_xdf *objfmt_xdf = (yasm_objfmt_xdf *)object->objfmt;
    xdf_objfmt_output_info info;
    unsigned char *localbuf;
    unsigned long symtab_count = 0;

    info.object = object;
    info.objfmt_xdf = objfmt_xdf;
    info.errwarns = errwarns;
    info.f = f;
    info.buf = yasm_xmalloc(REGULAR_OUTBUF_SIZE);

    /* Allocate space for headers by seeking forward */
    if (fseek(f, (long)(16+40*(objfmt_xdf->parse_scnum)), SEEK_SET) < 0) {
        yasm__fatal(N_("could not seek on output file"));
        /*@notreached@*/
        return;
    }

    /* Get number of symbols */
    info.indx = 0;
    info.all_syms = 1;  /* force all syms into symbol table */
    yasm_symtab_traverse(object->symtab, &info, xdf_objfmt_count_sym);
    symtab_count = info.indx;

    /* Get file offset of start of string table */
    info.strtab_offset = 16+40*(objfmt_xdf->parse_scnum)+16*symtab_count;

    /* Output symbol table */
    yasm_symtab_traverse(object->symtab, &info, xdf_objfmt_output_sym);

    /* Output string table */
    yasm_symtab_traverse(object->symtab, &info, xdf_objfmt_output_str);

    /* Section data/relocs */
    if (yasm_object_sections_traverse(object, &info,
                                      xdf_objfmt_output_section))
        return;

    /* Write headers */
    if (fseek(f, 0, SEEK_SET) < 0) {
        yasm__fatal(N_("could not seek on output file"));
        /*@notreached@*/
        return;
    }

    localbuf = info.buf;
    YASM_WRITE_32_L(localbuf, XDF_MAGIC);       /* magic number */
    YASM_WRITE_32_L(localbuf, objfmt_xdf->parse_scnum); /* number of sects */
    YASM_WRITE_32_L(localbuf, symtab_count);            /* number of symtabs */
    /* size of sect headers + symbol table + strings */
    YASM_WRITE_32_L(localbuf, info.strtab_offset-16);
    fwrite(info.buf, 16, 1, f);

    yasm_object_sections_traverse(object, &info, xdf_objfmt_output_secthead);

    yasm_xfree(info.buf);
}

static void
xdf_objfmt_destroy(yasm_objfmt *objfmt)
{
    yasm_xfree(objfmt);
}

static xdf_section_data *
xdf_objfmt_init_new_section(yasm_object *object, yasm_section *sect,
                            const char *sectname, unsigned long line)
{
    yasm_objfmt_xdf *objfmt_xdf = (yasm_objfmt_xdf *)object->objfmt;
    xdf_section_data *data;
    yasm_symrec *sym;

    data = yasm_xmalloc(sizeof(xdf_section_data));
    data->scnum = objfmt_xdf->parse_scnum++;
    data->flags = 0;
    data->addr = NULL;
    data->vaddr = NULL;
    data->scnptr = 0;
    data->size = 0;
    data->relptr = 0;
    data->nreloc = 0;
    yasm_section_add_data(sect, &xdf_section_data_cb, data);

    sym = yasm_symtab_define_label(object->symtab, sectname,
                                   yasm_section_bcs_first(sect), 1, line);
    data->sym = sym;
    return data;
}

static yasm_section *
xdf_objfmt_add_default_section(yasm_object *object)
{
    yasm_section *retval;
    xdf_section_data *xsd;
    int isnew;

    retval = yasm_object_get_general(object, ".text", 0, 1, 0, &isnew, 0);
    if (isnew) {
        xsd = xdf_objfmt_init_new_section(object, retval, ".text", 0);
        yasm_section_set_default(retval, 1);
    }
    return retval;
}

static int
xdf_helper_use(void *obj, yasm_valparam *vp, unsigned long line, void *d,
               uintptr_t bits)
{
    yasm_object *object = (yasm_object *)obj;
    unsigned long *flags = (unsigned long *)d;
    *flags &= ~(XDF_SECT_USE_16|XDF_SECT_USE_32|XDF_SECT_USE_64);
    switch (bits) {
        case 16: *flags |= XDF_SECT_USE_16; break;
        case 32: *flags |= XDF_SECT_USE_32; break;
        case 64: *flags |= XDF_SECT_USE_64; break;
    };
    yasm_arch_set_var(object->arch, "mode_bits", bits);
    return 0;
}

static /*@observer@*/ /*@null@*/ yasm_section *
xdf_objfmt_section_switch(yasm_object *object, yasm_valparamhead *valparams,
                          /*@unused@*/ /*@null@*/
                          yasm_valparamhead *objext_valparams,
                          unsigned long line)
{
    yasm_valparam *vp;
    yasm_section *retval;
    int isnew;
    int flags_override = 0;
    const char *sectname;
    int resonly = 0;
    xdf_section_data *xsd;
    unsigned long align = 0;

    struct xdf_section_switch_data {
        /*@only@*/ /*@null@*/ yasm_intnum *absaddr;
        /*@only@*/ /*@null@*/ yasm_intnum *vaddr;
        /*@only@*/ /*@null@*/ yasm_intnum *align_intn;
        unsigned long flags;
    } data;

    static const yasm_dir_help help[] = {
        { "use16", 0, xdf_helper_use,
          offsetof(struct xdf_section_switch_data, flags), 16 },
        { "use32", 0, xdf_helper_use,
          offsetof(struct xdf_section_switch_data, flags), 32 },
        { "use64", 0, xdf_helper_use,
          offsetof(struct xdf_section_switch_data, flags), 64 },
        { "bss", 0, yasm_dir_helper_flag_or,
          offsetof(struct xdf_section_switch_data, flags), XDF_SECT_BSS },
        { "flat", 0, yasm_dir_helper_flag_or,
          offsetof(struct xdf_section_switch_data, flags), XDF_SECT_FLAT },
        { "absolute", 1, yasm_dir_helper_intn,
          offsetof(struct xdf_section_switch_data, absaddr), 0 },
        { "virtual", 1, yasm_dir_helper_intn,
          offsetof(struct xdf_section_switch_data, vaddr), 0 },
        { "align", 1, yasm_dir_helper_intn,
          offsetof(struct xdf_section_switch_data, align_intn), 0 }
    };

    data.absaddr = NULL;
    data.vaddr = NULL;
    data.align_intn = NULL;
    data.flags = 0;

    vp = yasm_vps_first(valparams);
    sectname = yasm_vp_string(vp);
    if (!sectname)
        return NULL;
    vp = yasm_vps_next(vp);

    flags_override = yasm_dir_helper(object, vp, line, help, NELEMS(help),
                                     &data, yasm_dir_helper_valparam_warn);
    if (flags_override < 0)
        return NULL;    /* error occurred */

    if (data.absaddr)
        data.flags |= XDF_SECT_ABSOLUTE;
    if (data.align_intn) {
        align = yasm_intnum_get_uint(data.align_intn);
        yasm_intnum_destroy(data.align_intn);

        /* Alignments must be a power of two. */
        if (!is_exp2(align)) {
            yasm_error_set(YASM_ERROR_VALUE,
                           N_("argument to `%s' is not a power of two"),
                           "align");
            if (data.vaddr)
                yasm_intnum_destroy(data.vaddr);
            if (data.absaddr)
                yasm_intnum_destroy(data.absaddr);
            return NULL;
        }

        /* Check to see if alignment is supported size */
        if (align > 4096) {
            yasm_error_set(YASM_ERROR_VALUE,
                           N_("XDF does not support alignments > 4096"));
            if (data.vaddr)
                yasm_intnum_destroy(data.vaddr);
            if (data.absaddr)
                yasm_intnum_destroy(data.absaddr);
            return NULL;
        }
    }

    retval = yasm_object_get_general(object, sectname, align, 1, resonly,
                                     &isnew, line);

    if (isnew)
        xsd = xdf_objfmt_init_new_section(object, retval, sectname, line);
    else
        xsd = yasm_section_get_data(retval, &xdf_section_data_cb);

    if (isnew || yasm_section_is_default(retval)) {
        yasm_section_set_default(retval, 0);
        xsd->flags = data.flags;
        if (data.absaddr) {
            if (xsd->addr)
                yasm_intnum_destroy(xsd->addr);
            xsd->addr = data.absaddr;
        }
        if (data.vaddr) {
            if (xsd->vaddr)
                yasm_intnum_destroy(xsd->vaddr);
            xsd->vaddr = data.vaddr;
        }
        yasm_section_set_align(retval, align, line);
    } else if (flags_override)
        yasm_warn_set(YASM_WARN_GENERAL,
                      N_("section flags ignored on section redeclaration"));
    return retval;
}

static /*@observer@*/ /*@null@*/ yasm_symrec *
xdf_objfmt_get_special_sym(yasm_object *object, const char *name,
                           const char *parser)
{
    return NULL;
}

static void
xdf_section_data_destroy(void *data)
{
    xdf_section_data *xsd = (xdf_section_data *)data;
    if (xsd->addr)
        yasm_intnum_destroy(xsd->addr);
    if (xsd->vaddr)
        yasm_intnum_destroy(xsd->vaddr);
    yasm_xfree(data);
}

static void
xdf_section_data_print(void *data, FILE *f, int indent_level)
{
    xdf_section_data *xsd = (xdf_section_data *)data;

    fprintf(f, "%*ssym=\n", indent_level, "");
    yasm_symrec_print(xsd->sym, f, indent_level+1);
    fprintf(f, "%*sscnum=%ld\n", indent_level, "", xsd->scnum);
    fprintf(f, "%*sflags=0x%x\n", indent_level, "", xsd->flags);
    fprintf(f, "%*saddr=", indent_level, "");
    yasm_intnum_print(xsd->addr, f);
    fprintf(f, "%*svaddr=", indent_level, "");
    yasm_intnum_print(xsd->vaddr, f);
    fprintf(f, "%*sscnptr=0x%lx\n", indent_level, "", xsd->scnptr);
    fprintf(f, "%*ssize=%ld\n", indent_level, "", xsd->size);
    fprintf(f, "%*srelptr=0x%lx\n", indent_level, "", xsd->relptr);
    fprintf(f, "%*snreloc=%ld\n", indent_level, "", xsd->nreloc);
}

static void
xdf_symrec_data_destroy(void *data)
{
    yasm_xfree(data);
}

static void
xdf_symrec_data_print(void *data, FILE *f, int indent_level)
{
    xdf_symrec_data *xsd = (xdf_symrec_data *)data;

    fprintf(f, "%*ssymtab index=%lu\n", indent_level, "", xsd->index);
}

/* Define valid debug formats to use with this object format */
static const char *xdf_objfmt_dbgfmt_keywords[] = {
    "null",
    NULL
};

/* Define objfmt structure -- see objfmt.h for details */
yasm_objfmt_module yasm_xdf_LTX_objfmt = {
    "Extended Dynamic Object",
    "xdf",
    "xdf",
    32,
    xdf_objfmt_dbgfmt_keywords,
    "null",
    NULL,       /* no directives */
    xdf_objfmt_create,
    xdf_objfmt_output,
    xdf_objfmt_destroy,
    xdf_objfmt_add_default_section,
    xdf_objfmt_section_switch,
    xdf_objfmt_get_special_sym
};