path: root/usr/src/lib/libdwarf/common/pro_frame.c

/*

  Copyright (C) 2000,2004 Silicon Graphics, Inc.  All Rights Reserved.
  Portions Copyright 2011-2017  David Anderson. All Rights Reserved.
  Portions Copyright 2012 SN Systems Ltd. All rights reserved.

  This program is free software; you can redistribute it
  and/or modify it under the terms of version 2.1 of the
  GNU Lesser General Public License as published by the Free
  Software Foundation.

  This program is distributed in the hope that it would be
  useful, but WITHOUT ANY WARRANTY; without even the implied
  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.

  Further, this software is distributed without any warranty
  that it is free of the rightful claim of any third person
  regarding infringement or the like.  Any license provided
  herein, whether implied or otherwise, applies only to this
  software file.  Patent licenses, if any, provided herein
  do not apply to combinations of this program with other
  software, or any other product whatsoever.

  You should have received a copy of the GNU Lesser General
  Public License along with this program; if not, write the
  Free Software Foundation, Inc., 51 Franklin Street - Fifth
  Floor, Boston MA 02110-1301, USA.

*/

#include "config.h"
#include "libdwarfdefs.h"
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "pro_incl.h"
#include <stddef.h>
#include "dwarf.h"
#include "libdwarf.h"
#include "pro_opaque.h"
#include "pro_error.h"
#include "pro_alloc.h"
#include "pro_encode_nm.h"
#include "pro_frame.h"

#define SIZEOFT16 2
#define SIZEOFT32 4
#define SIZEOFT64 8

#ifdef WORDS_BIGENDIAN
#define ASNOUT(t,s,l)                       \
    do {                                    \
        unsigned sbyte = 0;                 \
        const char *p = 0;                        \
        if (l > sizeof(s)) {                \
            _dwarf_p_error(dbg, error, DW_DLE_DEBUG_FRAME_LENGTH_BAD);\
            return DW_DLV_ERROR;            \
        }                                   \
        sbyte = sizeof(s) - l;              \
        p = (const char *)(&s);             \
        dbg->de_copy_word(t,(const void *)(p+sbyte),l);\
    } while (0)
#else /* LITTLEENDIAN */
#define ASNOUT(t,s,l)                       \
    do {                                    \
        const char *p = 0;                  \
        if (l > sizeof(s)) {                \
            _dwarf_p_error(dbg, error, DW_DLE_DEBUG_FRAME_LENGTH_BAD);\
            return DW_DLV_ERROR;            \
        }                                   \
        p = (const char *)(&s);             \
        dbg->de_copy_word(t,(const void *)p,l);  \
    } while (0)
#endif /* ENDIANNESS */


static void _dwarf_pro_add_to_fde(Dwarf_P_Fde fde,
    Dwarf_P_Frame_Pgm inst);

/*  This function adds a cie struct to the debug pointer. Its in the
    form of a linked list.
    augmenter: string reps augmentation (implementation defined)
    code_align: alignment of code
    data_align: alignment of data
    init_bytes: byts having initial instructions
    init_n_bytes: number of bytes of initial instructions */


Dwarf_Unsigned
dwarf_add_frame_cie(Dwarf_P_Debug dbg,
    char *augmenter,
    Dwarf_Small code_align,
    Dwarf_Small data_align,
    Dwarf_Small return_reg,
    Dwarf_Ptr init_bytes,
    Dwarf_Unsigned init_n_bytes,
    Dwarf_Error * error)
{
    Dwarf_Unsigned index = 0;
    int res = 0;

    res = dwarf_add_frame_cie_a(dbg,augmenter, code_align,
        data_align,return_reg,init_bytes,
        init_n_bytes,
        &index,error);
    if (res != DW_DLV_OK) {
        return DW_DLV_NOCOUNT;
    }
    return index;
}


int
dwarf_add_frame_cie_a(Dwarf_P_Debug dbg,
    char *augmenter,
    Dwarf_Small code_align,
    Dwarf_Small data_align,
    Dwarf_Small return_reg,
    Dwarf_Ptr init_bytes,
    Dwarf_Unsigned init_n_bytes,
    Dwarf_Unsigned * cie_index_out,
    Dwarf_Error * error)
{
    Dwarf_P_Cie curcie;
    char *tmpaug = 0;

    if (dbg->de_frame_cies == NULL) {
        dbg->de_frame_cies = (Dwarf_P_Cie)
            _dwarf_p_get_alloc(dbg, sizeof(struct Dwarf_P_Cie_s));
        if (dbg->de_frame_cies == NULL) {
            DWARF_P_DBG_ERROR(dbg, DW_DLE_CIE_ALLOC, DW_DLV_ERROR);
        }
        curcie = dbg->de_frame_cies;
        dbg->de_n_cie = 1;
        dbg->de_last_cie = curcie;
    } else {
        curcie = dbg->de_last_cie;
        curcie->cie_next = (Dwarf_P_Cie)
            _dwarf_p_get_alloc(dbg, sizeof(struct Dwarf_P_Cie_s));
        if (curcie->cie_next == NULL) {
            DWARF_P_DBG_ERROR(dbg, DW_DLE_CIE_ALLOC, DW_DLV_ERROR);
        }
        curcie = curcie->cie_next;
        dbg->de_n_cie++;
        dbg->de_last_cie = curcie;
    }
    curcie->cie_version = 1;
    if (dbg->de_output_version > 2) {
        curcie->cie_version = dbg->de_output_version;
    } else {
        /*  V2 dwarf has debug_frame as version 1, there
            is no 2 used in this section. */
        curcie->cie_version = 1;
    }
    tmpaug = (char *)_dwarf_p_get_alloc(dbg,strlen(augmenter)+1);
    if (!tmpaug) {
        DWARF_P_DBG_ERROR(dbg, DW_DLE_CIE_ALLOC, DW_DLV_ERROR);
    }
    strcpy(tmpaug,augmenter);
    curcie->cie_aug = tmpaug;
    curcie->cie_code_align = code_align;
    curcie->cie_data_align = data_align;
    curcie->cie_ret_reg = return_reg;
    curcie->cie_inst = (char *) init_bytes;
    curcie->cie_inst_bytes = (long) init_n_bytes;
    curcie->cie_next = NULL;
    *cie_index_out =  dbg->de_n_cie;
    return DW_DLV_OK;
}


/*  This functions adds a fde struct to the debug pointer. Its in the
    form of a linked list.
    die: subprogram/function die corresponding to this fde
    cie: cie referred to by this fde, obtained from call to
        add_frame_cie() routine.
    virt_addr: beginning address
    code_len: length of code reps by the fde */
/*ARGSUSED*/                   /* pretend all args used */
Dwarf_Unsigned
dwarf_add_frame_fde(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx, Dwarf_Error * error)
{
    Dwarf_Unsigned index = 0;
    int res = 0;

    res = dwarf_add_frame_fde_c(dbg, fde, die, cie, virt_addr,
        code_len, symidx, 0, 0,&index, error);
    if (res != DW_DLV_OK) {
        return DW_DLV_NOCOUNT;
    }
    return index;
}

/*  There is no dwarf_add_frame_fde_a */
/*ARGSUSED10*/
Dwarf_Unsigned
dwarf_add_frame_fde_b(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx,
    Dwarf_Unsigned symidx_of_end,
    Dwarf_Addr offset_from_end_sym,
    Dwarf_Error * error)
{
    Dwarf_Unsigned index = 0;
    int res = 0;

    res = dwarf_add_frame_fde_c(dbg,fde,die,cie,
        virt_addr,code_len,symidx,symidx_of_end,
        offset_from_end_sym,&index,error);
    if (res != DW_DLV_OK) {
        return DW_DLV_NOCOUNT;
    }
    return index;
}

/*  New December 2018 */
int
dwarf_add_frame_fde_c(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx,
    Dwarf_Unsigned symidx_of_end,
    Dwarf_Addr offset_from_end_sym,
    Dwarf_Unsigned *index_to_fde,
    UNUSEDARG Dwarf_Error * error)
{
    Dwarf_P_Fde curfde;

    fde->fde_die = die;
    fde->fde_cie = (long) cie;
    fde->fde_initloc = virt_addr;
    fde->fde_r_symidx = symidx;
    fde->fde_addr_range = code_len;
    fde->fde_offset_into_exception_tables = DW_DLX_NO_EH_OFFSET;
    fde->fde_exception_table_symbol = 0;
    fde->fde_end_symbol_offset = offset_from_end_sym;
    fde->fde_end_symbol = symidx_of_end;
    fde->fde_dbg = dbg;

    curfde = dbg->de_last_fde;
    if (curfde == NULL) {
        dbg->de_frame_fdes = fde;
        dbg->de_last_fde = fde;
        dbg->de_n_fde = 1;
    } else {
        curfde->fde_next = fde;
        dbg->de_last_fde = fde;
        dbg->de_n_fde++;
    }
    *index_to_fde = dbg->de_n_fde;
    return DW_DLV_OK;
}

/*  This function adds information to an fde. The fde is
    linked into the linked list of fde's maintained in the Dwarf_P_Debug
    structure.
    dbg: The debug descriptor.
    fde: The fde to be added.
    die: subprogram/function die corresponding to this fde
    cie: cie referred to by this fde, obtained from call to
        add_frame_cie() routine.
    virt_addr: beginning address
    code_len: length of code reps by the fde
    symidx: The symbol id of the symbol wrt to which relocation needs
        to be performed for 'virt_addr'.
    offset_into_exception_tables: The start of exception tables for
        this function (indicated as an offset into the exception
        tables). A value of -1 indicates that there is no exception
        table entries associated with this function.
    exception_table_symbol: The symbol id of the section for exception
        tables wrt to which the offset_into_exception_tables will
        be relocated. */
Dwarf_Unsigned
dwarf_add_frame_info(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx,
    Dwarf_Signed offset_into_exception_tables,
    Dwarf_Unsigned exception_table_symbol,
    Dwarf_Error * error)
{
    Dwarf_Unsigned fde_index = 0;
    int res = 0;

    res = dwarf_add_frame_info_c(dbg, fde, die, cie, virt_addr,
        code_len, symidx,
        /* end_symbol */ 0,
        /* offset_from_end */ 0,
        offset_into_exception_tables,
        exception_table_symbol,
        &fde_index, error);
    if (res != DW_DLV_OK) {
        return DW_DLV_NOCOUNT;
    }
    return fde_index;
}

/*ARGSUSED*/                   /* pretend all args used */
Dwarf_Unsigned
dwarf_add_frame_info_b(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx,
    Dwarf_Unsigned end_symidx,
    Dwarf_Unsigned offset_from_end_symbol,
    Dwarf_Signed offset_into_exception_tables,
    Dwarf_Unsigned exception_table_symbol,
    UNUSEDARG Dwarf_Error * error)
{
    Dwarf_Unsigned fde_index = 0;
    int res = 0;

    res = dwarf_add_frame_info_c(dbg, fde, die, cie, virt_addr,
        code_len, symidx, end_symidx,
        offset_from_end_symbol,
        offset_into_exception_tables,
        exception_table_symbol,
        &fde_index, error);
    if (res != DW_DLV_OK) {
        return DW_DLV_NOCOUNT;
    }
    return fde_index;
}

int
dwarf_add_frame_info_c(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,
    Dwarf_P_Die die,
    Dwarf_Unsigned cie,
    Dwarf_Unsigned virt_addr,
    Dwarf_Unsigned code_len,
    Dwarf_Unsigned symidx,
    Dwarf_Unsigned end_symidx,
    Dwarf_Unsigned offset_from_end_symbol,
    Dwarf_Signed offset_into_exception_tables,
    Dwarf_Unsigned exception_table_symbol,
    Dwarf_Unsigned *fde_index_out,
    UNUSEDARG Dwarf_Error * error)
{
    Dwarf_P_Fde curfde;

    fde->fde_die = die;
    fde->fde_cie = (long) cie;
    fde->fde_initloc = virt_addr;
    fde->fde_r_symidx = symidx;
    fde->fde_addr_range = code_len;
    fde->fde_offset_into_exception_tables =
        offset_into_exception_tables;
    fde->fde_exception_table_symbol = exception_table_symbol;
    fde->fde_end_symbol_offset = offset_from_end_symbol;
    fde->fde_end_symbol = end_symidx;
    fde->fde_dbg = dbg;

    curfde = dbg->de_last_fde;
    if (curfde == NULL) {
        dbg->de_frame_fdes = fde;
        dbg->de_last_fde = fde;
        dbg->de_n_fde = 1;
    } else {
        curfde->fde_next = fde;
        dbg->de_last_fde = fde;
        dbg->de_n_fde++;
    }
    *fde_index_out = dbg->de_n_fde;
    return DW_DLV_OK;
}

/* This is an alternate to inserting frame instructions
   one instruction at a time.  But use either this
   or instruction level, not both in one fde. */
int
dwarf_insert_fde_inst_bytes(Dwarf_P_Debug dbg,
    Dwarf_P_Fde fde,Dwarf_Unsigned len, Dwarf_Ptr ibytes,
    Dwarf_Error *error)
{
    if (len == 0) {
        return DW_DLV_OK;
    }
    if (fde->fde_block || fde->fde_inst) {
        DWARF_P_DBG_ERROR(dbg, DW_DLE_DUPLICATE_INST_BLOCK,
            DW_DLV_ERROR);
    }
    fde->fde_block = (Dwarf_Ptr)_dwarf_p_get_alloc(dbg, len);
    memcpy(fde->fde_block,ibytes,len);
    fde->fde_inst_block_size = len;
    fde->fde_n_bytes += len;
    return DW_DLV_OK;
}



/* Create a new fde. */
Dwarf_P_Fde
dwarf_new_fde(Dwarf_P_Debug dbg, Dwarf_Error * error)
{
    Dwarf_P_Fde fde = 0;
    int res = 0;

    res = dwarf_new_fde_a(dbg,&fde,error);
    if (res != DW_DLV_OK) {
        return (Dwarf_P_Fde) DW_DLV_BADADDR;
    }
    return fde;
}
int
dwarf_new_fde_a(Dwarf_P_Debug dbg,
    Dwarf_P_Fde *fde_out,
    Dwarf_Error * error)
{
    Dwarf_P_Fde fde;

    fde = (Dwarf_P_Fde)
        _dwarf_p_get_alloc(dbg, sizeof(struct Dwarf_P_Fde_s));
    if (fde == NULL) {
        DWARF_P_DBG_ERROR(dbg, DW_DLE_FDE_ALLOC, DW_DLV_ERROR);
    }
    fde->fde_dbg = dbg;
    fde->fde_uwordb_size = dbg->de_dwarf_offset_size;
    *fde_out = fde;
    return DW_DLV_OK;
}


/*  Add a cfe_offset instruction to the fde passed in. */
Dwarf_P_Fde
dwarf_fde_cfa_offset(Dwarf_P_Fde fde,
    Dwarf_Unsigned reg,
    Dwarf_Signed offset,
    Dwarf_Error * error)
{
    int res = 0;

    res = dwarf_fde_cfa_offset_a(fde,reg,offset,error);
    if (res != DW_DLV_OK) {
        return (Dwarf_P_Fde) DW_DLV_BADADDR;
    }
    return fde;
}


int
dwarf_fde_cfa_offset_a(Dwarf_P_Fde fde,
    Dwarf_Unsigned reg,
    Dwarf_Signed offset,
    Dwarf_Error * error)
{
    Dwarf_Ubyte opc, regno;
    char *ptr = 0;
    Dwarf_P_Frame_Pgm curinst;
    int nbytes = 0;
    int res = 0;
    char buff1[ENCODE_SPACE_NEEDED];
    Dwarf_P_Debug dbg = fde->fde_dbg;

    curinst = (Dwarf_P_Frame_Pgm)
        _dwarf_p_get_alloc(dbg, sizeof(struct Dwarf_P_Frame_Pgm_s));
    if (curinst == NULL) {
        DWARF_P_DBG_ERROR(dbg, DW_DLE_FPGM_ALLOC, DW_DLV_ERROR);
    }
    opc = DW_CFA_offset;
    regno = reg;
    if (regno & 0xc0) {
        DWARF_P_DBG_ERROR(dbg, DW_DLE_REGNO_OVFL,DW_DLV_ERROR);
    }
    opc = opc | regno;          /* lower 6 bits are register number */
    curinst->dfp_opcode = opc;
    res = _dwarf_pro_encode_leb128_nm(offset, &nbytes,
        buff1, sizeof(buff1));
    if (res != DW_DLV_OK) {
        _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
        return DW_DLV_ERROR;
    }
    ptr = (char *) _dwarf_p_get_alloc(dbg, nbytes);
    if (ptr == NULL) {
        _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
        return DW_DLV_ERROR;
    }
    memcpy(ptr, buff1, nbytes);

    curinst->dfp_args = ptr;
    curinst->dfp_nbytes = nbytes;
    curinst->dfp_next = NULL;

    _dwarf_pro_add_to_fde(fde, curinst);
    return DW_DLV_OK;
}

/*  Generic routine to add opcode to fde instructions. val1 and
    val2 are parameters whose interpretation depends on the 'op'.

    This does not work properly for  DW_DLC_SYMBOLIC_RELOCATIONS
    for DW_CFA_set_loc or DW_DVA_advance_loc* 'op', as
    these ops normally are addresses or (DW_CFA_set_loc)
    or code lengths (DW_DVA_advance_loc*) and such must be
    represented with relocations and symbol indices for
    DW_DLC_SYMBOLIC_RELOCATIONS.

    This does not treat all DW_CFA instructions yet.

    For certain operations a val? value must be
    signed (though passed in as unsigned here).

    Does not check that the frame
    version is 3(for dwarf3) or 4 (for dwarf4) or 5
    when applying operations that are only valid for
    particular versions. */
Dwarf_P_Fde
dwarf_add_fde_inst(Dwarf_P_Fde fde,
    Dwarf_Small op,
    Dwarf_Unsigned val1,
    Dwarf_Unsigned val2, Dwarf_Error * error)
{
    int res = 0;

    res = dwarf_add_fde_inst_a(fde,op,val1,val2,error);
    if (res != DW_DLV_OK) {
        return ((Dwarf_P_Fde) DW_DLV_BADADDR);
    }
    return fde;
}

/*  December 2018. A more sensible return value. */
int
dwarf_add_fde_inst_a(Dwarf_P_Fde fde,
    Dwarf_Small op,
    Dwarf_Unsigned val1,
    Dwarf_Unsigned val2,
    Dwarf_Error * error)
{
    Dwarf_P_Frame_Pgm curinst;
    int nbytes = 0;
    int nbytes1 = 0;
    int nbytes2 = 0;
    Dwarf_Ubyte db = 0;
    Dwarf_Half dh = 0;
    Dwarf_Unsigned du = 0;
    char *ptr = 0;
    int res = 0;
    char buff1[ENCODE_SPACE_NEEDED];
    char buff2[ENCODE_SPACE_NEEDED];
    Dwarf_P_Debug dbg = fde->fde_dbg;
    /*  This is a hack telling the code when to transform
        a value to a signed leb number. */
    int signed_second = 0;
    int signed_first = 0;


    buff1[0] = 0;
    buff2[0] = 0;
    curinst = (Dwarf_P_Frame_Pgm)
        _dwarf_p_get_alloc(dbg, sizeof(struct Dwarf_P_Frame_Pgm_s));
    if (curinst == NULL) {
        _dwarf_p_error(dbg, error, DW_DLE_FPGM_ALLOC);
        return DW_DLV_ERROR;
    }
    switch (op) {

    case DW_CFA_advance_loc: {
        if (val1 <= 0x3f) {
            db = val1;
            op |= db;
        } else if (!(val1& ~0xff)) {
            op = DW_CFA_advance_loc1;
            db = val1;
            ptr = (char *) _dwarf_p_get_alloc(dbg, 1);
            if (ptr == NULL) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            memcpy((void *) ptr, (const void *) &db, 1);
            nbytes = 1;
        } else if (!(val1& (~(Dwarf_Unsigned)0xffff))) {
            if (sizeof(dh) < SIZEOFT16) {
                _dwarf_p_error(dbg, error,
                    DW_DLE_DEBUG_FRAME_LENGTH_BAD);
                return DW_DLV_ERROR;
            }
            op = DW_CFA_advance_loc2;
            dh = val1;
            ptr = (char *) _dwarf_p_get_alloc(dbg, SIZEOFT16);
            if (ptr == NULL) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            /*  No byte swapping, assuming running at
                target endianness. */
            ASNOUT((void *) ptr, dh, SIZEOFT16);
            nbytes = SIZEOFT16;
        } else if (!(val1& ~(Dwarf_Unsigned)0xffffffff)) {
            if (sizeof(du) < SIZEOFT32) {
                _dwarf_p_error(dbg, error,
                    DW_DLE_DEBUG_FRAME_LENGTH_BAD);
                return DW_DLV_ERROR;
            }
            op = DW_CFA_advance_loc4;
            du = val1;
            ptr = (char *) _dwarf_p_get_alloc(dbg, SIZEOFT32);
            if (ptr == NULL) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            ASNOUT((void *) ptr, du, SIZEOFT32);
            nbytes = SIZEOFT32;
        } else {
            if (sizeof(du) < SIZEOFT64) {
                _dwarf_p_error(dbg, error,
                    DW_DLE_DEBUG_FRAME_LENGTH_BAD);
                return DW_DLV_ERROR;
            }
            op = DW_CFA_MIPS_advance_loc8;
            du = val1;
            ptr = (char *) _dwarf_p_get_alloc(dbg,
                SIZEOFT64);
            if (ptr == NULL) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            /*  No byte swapping, assuming running at
                target endianness. */
            ASNOUT((void *) ptr, du, SIZEOFT64);
            nbytes = SIZEOFT64;
        }
        break;
    }
    case DW_CFA_offset:
        if (val1 <= MAX_6_BIT_VALUE) {
            db = val1;
            op |= db;
            res = _dwarf_pro_encode_leb128_nm(val2, &nbytes,
                buff1, sizeof(buff1));
            if (res != DW_DLV_OK) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            ptr = (char *) _dwarf_p_get_alloc(dbg, nbytes);
            if (ptr == NULL) {
                _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
                return DW_DLV_ERROR;
            }
            memcpy(ptr, buff1, nbytes);

        } else {
            op = DW_CFA_offset_extended;
            goto two_leb;
        }
        break;
    case DW_CFA_offset_extended_sf: /* DWARF3 */
        signed_second = 1;
        goto two_leb;
    case DW_CFA_offset_extended:
        goto two_leb;

    case DW_CFA_undefined:
    case DW_CFA_same_value:
        goto one_leb;

    case DW_CFA_val_offset:
        goto two_leb;
    case DW_CFA_val_offset_sf:
        signed_second = 1;
        goto two_leb;
    case DW_CFA_def_cfa_sf:
        signed_second = 1;
        goto two_leb;
    case DW_CFA_register:
    case DW_CFA_def_cfa:
    two_leb:
        res = _dwarf_pro_encode_leb128_nm(val1, &nbytes1,
            buff1, sizeof(buff1));
        if (res != DW_DLV_OK) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }
        if (!signed_second) {
            res = _dwarf_pro_encode_leb128_nm(val2, &nbytes2,
                buff2, sizeof(buff2));
        } else {
            Dwarf_Signed val2s = val2;
            res = _dwarf_pro_encode_signed_leb128_nm(val2s, &nbytes2,
                buff2, sizeof(buff2));
        }
        if (res != DW_DLV_OK) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }

        res = _dwarf_pro_encode_leb128_nm(val2, &nbytes2,
            buff2, sizeof(buff2));
        if (res != DW_DLV_OK) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }

        ptr = (char *) _dwarf_p_get_alloc(dbg, nbytes1 + nbytes2);
        if (ptr == NULL) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }
        memcpy(ptr, buff1, nbytes1);
        memcpy(ptr + nbytes1, buff2, nbytes2);
        nbytes = nbytes1 + nbytes2;
        break;

    case DW_CFA_def_cfa_offset_sf: /* DWARF3 */
        signed_first = 1;
        goto one_leb;
    case DW_CFA_def_cfa_register:
    case DW_CFA_def_cfa_offset:
    one_leb:
        if (!signed_first) {
            res = _dwarf_pro_encode_leb128_nm(val1, &nbytes,
                buff1, sizeof(buff1));
        } else {
            Dwarf_Signed val1s = val1;
            res = _dwarf_pro_encode_signed_leb128_nm(val1s, &nbytes,
                buff1, sizeof(buff1));
        }
        if (res != DW_DLV_OK) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }
        ptr = (char *) _dwarf_p_get_alloc(dbg, nbytes);
        if (ptr == NULL) {
            _dwarf_p_error(dbg, error, DW_DLE_STRING_ALLOC);
            return DW_DLV_ERROR;
        }
        memcpy(ptr, buff1, nbytes);
        break;
    case DW_CFA_def_cfa_expression: /* DWARF3 */
        /*  FIXME: argument is dwarf expr, not handled yet. */
    case DW_CFA_expression: /* DWARF3 */
        /*  First arg: ULEB reg num. 2nd arg dwarf expr in form block.
            FIXME: not handled yet. */
    case DW_CFA_val_expression: /* DWARF3f */
        /*  First arg: ULEB reg num. 2nd arg dwarf expr in form block.
            FIXME: not handled yet. */
    default:
        _dwarf_p_error(dbg, error, DW_DLE_DEBUGFRAME_ERROR);
        return DW_DLV_ERROR;
    }

    curinst->dfp_opcode = op;
    curinst->dfp_args = ptr;
    curinst->dfp_nbytes = nbytes;
    curinst->dfp_next = NULL;
    _dwarf_pro_add_to_fde(fde, curinst);
    return DW_DLV_OK;
}


/*  Instructions are added to an fde in the form of a linked
    list. This function manages the linked list. */
void
_dwarf_pro_add_to_fde(Dwarf_P_Fde fde, Dwarf_P_Frame_Pgm curinst)
{
    if (fde->fde_last_inst) {
        fde->fde_last_inst->dfp_next = curinst;
        fde->fde_last_inst = curinst;
        fde->fde_n_inst++;
        fde->fde_n_bytes +=
            (long) (curinst->dfp_nbytes + sizeof(Dwarf_Ubyte));
    } else {
        fde->fde_last_inst = curinst;
        fde->fde_inst = curinst;
        fde->fde_n_inst = 1;
        fde->fde_n_bytes =
            (long) (curinst->dfp_nbytes + sizeof(Dwarf_Ubyte));
    }
}