Line data    Source code

       1             : /* Look up the DIE in a reference-form attribute.
       2             :    Copyright (C) 2005-2010 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include <string.h>
      34             : #include "libdwP.h"
      35             : #include <dwarf.h>
      36             : 
      37             : 
      38             : Dwarf_Die *
      39      670574 : dwarf_formref_die (Dwarf_Attribute *attr, Dwarf_Die *result)
      40             : {
      41      670574 :   if (attr == NULL)
      42             :     return NULL;
      43             : 
      44      670574 :   struct Dwarf_CU *cu = attr->cu;
      45             : 
      46             :   Dwarf_Off offset;
      47      670574 :   if (attr->form == DW_FORM_ref_addr || attr->form == DW_FORM_GNU_ref_alt)
      48             :     {
      49             :       /* This has an absolute offset.  */
      50             : 
      51       12092 :       uint8_t ref_size = (cu->version == 2 && attr->form == DW_FORM_ref_addr
      52             :                           ? cu->address_size
      53             :                           : cu->offset_size);
      54             : 
      55       12092 :       Dwarf *dbg_ret = (attr->form == DW_FORM_GNU_ref_alt
      56       12092 :                         ? cu->dbg->alt_dwarf : cu->dbg);
      57             : 
      58       12092 :       if (dbg_ret == NULL)
      59             :         {
      60           0 :           __libdw_seterrno (DWARF_E_NO_ALT_DEBUGLINK);
      61           0 :           return NULL;
      62             :         }
      63             : 
      64       12092 :       if (__libdw_read_offset (cu->dbg, dbg_ret, IDX_debug_info, attr->valp,
      65             :                                ref_size, &offset, IDX_debug_info, 0))
      66             :         return NULL;
      67             : 
      68       12092 :       return INTUSE(dwarf_offdie) (dbg_ret, offset, result);
      69             :     }
      70             : 
      71             :   const unsigned char *datap;
      72             :   size_t size;
      73      658482 :   if (attr->form == DW_FORM_ref_sig8)
      74             :     {
      75             :       /* This doesn't have an offset, but instead a value we
      76             :          have to match in the .debug_types type unit headers.  */
      77             : 
      78           4 :       uint64_t sig = read_8ubyte_unaligned (cu->dbg, attr->valp);
      79           4 :       cu = Dwarf_Sig8_Hash_find (&cu->dbg->sig8_hash, sig, NULL);
      80           4 :       if (cu == NULL)
      81             :         /* Not seen before.  We have to scan through the type units.  */
      82             :         do
      83             :           {
      84           1 :             cu = __libdw_intern_next_unit (attr->cu->dbg, true);
      85           1 :             if (cu == NULL)
      86             :               {
      87           0 :                 __libdw_seterrno (INTUSE(dwarf_errno) ()
      88             :                                   ?: DWARF_E_INVALID_REFERENCE);
      89           0 :                 return NULL;
      90             :               }
      91             :           }
      92           1 :         while (cu->type_sig8 != sig);
      93             : 
      94           4 :       datap = cu->dbg->sectiondata[IDX_debug_types]->d_buf;
      95           4 :       size = cu->dbg->sectiondata[IDX_debug_types]->d_size;
      96           4 :       offset = cu->start + cu->type_offset;
      97             :     }
      98             :   else
      99             :     {
     100             :       /* Other forms produce an offset from the CU.  */
     101      658478 :       if (unlikely (__libdw_formref (attr, &offset) != 0))
     102             :         return NULL;
     103             : 
     104      658478 :       datap = cu->startp;
     105      658478 :       size = cu->endp - cu->startp;
     106             :     }
     107             : 
     108      658482 :   if (unlikely (offset >= size))
     109             :     {
     110           0 :       __libdw_seterrno (DWARF_E_INVALID_DWARF);
     111           0 :       return NULL;
     112             :     }
     113             : 
     114      658482 :   memset (result, '\0', sizeof (Dwarf_Die));
     115      658482 :   result->addr = (char *) datap + offset;
     116      658482 :   result->cu = cu;
     117      658482 :   return result;
     118             : }
     119             : INTDEF (dwarf_formref_die)